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Literature Update Sep - Oct 2010

Acta Odontologica Scandinavica

Vol. 68 No. 5 (September 2010)

Zhu Y, Xiao L, Shen D, Hao Y. Competition between yogurt probiotics and periodontal pathogens in vitro. Acta Odontol Scand 2010;68(5):261-268.

Four probiotic bacterial species (L bulgaricus,  S thermophilus,  L acidophilus and  Bifidobacterium) were isolated from yogurt to assess the antimicrobial activity versus various periodontal pathogens. All periodontal pathogens were inhibited by fresh yogurt but antimicrobial activity  was lower with heat-treated yogurt. However, neither yogurt inhibited the ‘protective’ bacteria  S sanguinis. Competition between the bacteria depended on the sequence of inoculation, and antimicrobial properties were reduced if both probiotic bacteria and periodontal pathogens were inoculated simultaneously. Probiotic yogurt and its bacteria can therefore inhibit certain periodontal pathogens but do not affect periodontal protective bacteria.

Clinical Implant Dentistry and Related Research

Vol. 12 No. 3 (September 2010)

Safii SH, Palmer RM, Wilson RF. Risk of implant failure and marginal bone loss in subjects with a history of periodontitis: a systematic review and meta-analysis. Clin Implant Dent Relat Res 2010;12(3):165-174.

A literature search was conducted for clinical studies comparing periodontal/peri-implant variables between healthy subjects and those with periodontitis. A total of 17 potential studies were identified, of which six compared implant treatment in periodontally compromised and periodontally healthy subjects. Meta-analysis of implant survival was possible for five studies and meta-analysis of peri-implant bone loss was possible for four studies. Periodontally healthy patients showed a significantly greater odds ratio for implant survival, while marginal bone loss was significantly greater in subjects with periodontitis. The risk of implant failure and marginal bone loss is therefore greater in patients with periodontitis.

Shabestari GO, Shayesteh YS, Khojasteh A, Alikhasi M, Moslemi N, Aminian A, Mazaeli R, Eslami B, Treister NS.  Implant placement in patients with oral bisphosphonate therapy: a case series. Clin Implant Dent Relat Res 2010;12(3):175-180.

A total of 21 patients with osteoporosis and who  were receiving bisphosphonate therapy received 46 implants, which were evaluated for probing depth, mobility, thread exposure and bleeding on probing. No signs of peri-implantitis were observed in any of the patients. Time  of bisphosphonate therapy relative to implant placement, implant location, type of prosthesis and opposing dentition had no significant influence. Bisphosphonate therapy before or after implant placement therefore did not jeopardize osseointegration or clinical or radiographic outcomes.

 Tözüm TF, Turkyilmaz I, Bal BT. Initial stability of two dental implant systems: influence of buccolingual width and probe orientation on resonance frequency measurements.  Clin Implant Dent Relat Res 2010;12(3):194-201.

Implants from two dental implant systems (diameters 3.75 mm and 4.2 mm) were placed in acrylic models and buccolingual thinning of the models was performed  in 2 mm increments from 0 to 8 mm. resonance frequency analysis were then performed. Implant stability quotient 8ISQ) significantly decreased for both implant systems and diameters for all time points of the acrylic block. Significantly higher ISQ values were observed for the implant system with more threads. However, ISQ measurement was affected by the orientation of the probe.

Kleis WK, Kämmerer PW, Hartmann S, Al-Nawas B, Wagner W. A comparison of three different attachment systems for mandibular two-implant overdentures: one-year report.   Clin Implant Dent Relat Res 2010;12(3):209-218.

Each of 60 patients with an edentulous mandible received two implants in the interforaminal region. After 3.5 months of healing, overdentures were placed using one of three different attachment systems (Locator attachment or one of two types of ball attachment [TG-O-Ring or Dal-Ro]).  Prosthodontic maintenance, biological complications, patient experience and oral  health-related quality of life were evaluated after 12 months. Eight of the 120 implants were lost after 1 year, giving an implant survival rate of 90.4%. A total of 34 complications occurred with the Locator system, 14 with the TG-O-Ring system and seven with the Dal-Ro system. No differences in biological complications or oral health-related quality of life were observed.

 

Clinical Oral Implants Research

Vol. 21 No. 9 (September 2010)

Caneva M, Salata LA, De Souza SS, Bressan E, Botticelli D, Lang NP. Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs. Clin Oral Implants Res 2010;21(9):885-890.

Cylindrical (3.3 mm diameter; control) or conical (5.0 mm diameter; test) implants were placed in extraction sockets in dog mandibles and bone resorption was evaluated after 4 months. Alveolar crest resorption was observed with both implant types and was more pronounced at the buccal aspect, but was significantly greater with the test implants. The control implants were associated with deeper lingual defects. Root formed wide implants therefore do not inhibit alveolar resorption.

Matarasso S, Rasperini G, Iorio Siciliano V, Salvi GE, Lang NP, Aglietta M. A 10-year retrospective analysis of radiographic bone-level changes of implants supporting single-unit crowns in periodontally compromised vs. periodontally healthy patients. Clin Oral Implants Res 2010;21(9):898-903.

Mean bone loss around two different types of implants placed in 20 periodontally healthy or periodontally compromised patients was retrospectively evaluated after 10 years. Implant survival ranged from 85-95% between the four groups, but the differences were  not statistically significant. Mean bone loss and the number of sites with bone loss ≥ 3 mm were significantly greater in the periodontally compromised patients, regardless of the implant system used.

Schwarz F, Ferrari D, Balic E, Buser D, Becker J, Sager M. Lateral ridge augmentation using equine- and bovine-derived cancellous bone blocks: a feasibility study in dogs. Clin Oral Implants Res 2010;21(9):904-912.

Box defects were created in the alveolar ridges of dog mandibles and treated with either equine- or bovine-derived cancellous bone block covered with a collagen membrane. After 12 weeks, bovine bone blocks were found to be embedded in fibrous connective tissue, with no signs of biodegradation. However, significantly increased cell-mediated degradation was found with the equine bone blocks, Bone ingrowth was also higher with the equine bone blocks, but the difference was not significant. Equine bone blocks did not appear to be associated with improved bone formation.

Merheb J, Coucke W, Jacobs R, Naert I, Quirynen M.  Influence of bone defects on implant stability. Clin Oral Implants Res 2010;21(9):919-923.

A total of 32 implants were placed in human cadaver jaws according to four types of bone defect: marginal bone loss, peri-apical bone defect, constant width dehiscence or constant length dehiscence. Implant stability was measured using the Periotest and Osstell devices before and during bone removal. Significant differences in implant stability were noted from  baseline after removal of 2 mm marginal bone, 5 mm (Osstell) or 8 mm (Periotest) of peri-apical bone, removal of up to 180° of the implant perimeter for a 6 mm long dehiscence, and after removal of 10 mm (Osstell) or 6 mm (Periotest) for a 3 mm wide dehiscence. The implant stability measurements therefore did not appear to be very sensitive regarding the detection of peri-implant bone loss.

 Lindgren C, Hallman M, Sennerby L, Sammons R. Back-scattered electron imaging and elemental analysis of retrieved bone tissue following sinus augmentation with deproteinized bovine bone or biphasic calcium phosphate. Clin Oral Implants Res 2010;21(9):924-930.

Bilateral maxillary sinus floor augmentation was performed in 11 patients using deproteinized bovine bone (DBB; Bio-Oss) in one side and biphasic calcium phosphate (BCO; Straumann BoneCeramic) in the contralateral side. Micro-implants were placed and removed after 8 months with the surrounding bone core. Both types of graft material were in direct contact with or surrounded by newly formed bone. Mean Ca/P ratios were 1.61 and 1.62 for DBB and DBB-augmented bone, respectively, and 1.5 and 1.52 for BCP and BCP-augmented bone, respectively, consistent with the dissolution and gradual substitution of the  β-TCP part of BCP over the healing period.

Rossi F, Ricci E, Marchetti C, Lang NP, Botticelli D. Early loading of single crowns supported by 6-mm-long implants with a moderately rough surface: a prospective 2-year follow-up cohort study. Clin Oral Implants Res 2010;21(9):937-943.

A total of 40 implants (6 mm long and either 4.1 mm or 4.8 mm wide) were placed in 35 patients, and implant survival, marginal bone loss and resonance frequency analysis (RFA) measurements were performed. The implant survival rate was 95% (two implants lost) after 2 years, and mean marginal bone loss was 0.34 ± 0.38 mm before loading and 0.23 ± 0.33 mm and 0.21 ± 0.39 mm at 1 and 2 years, respectively. Implant stability increased from implant placement to 6 weeks and the crown/implant ratio decreased from 1.5 at prosthesis placement to 1.8 at 2 years. High implant survival and moderate bone loss was therefore observed after 2 years, but longer-term investigations are necessary  to assess the reliability of short implants.

Mordenfeld A, Hallman M, Johansson CB, Albrektsson T. Histological and histomorphometrical analyses of biopsies harvested 11 years after maxillary sinus floor augmentation with deproteinized bovine and autogenous bone. Clin Oral Implants Res 2010;21(9):961-970.

Thirty maxillary sinuses in 20 patients were augmented with 80% deproteinized bovine bone and 20% autogenous bone. Biopsies were taken from 11 patients after 11 years and evaluated. Mean 44.7 ± 16.9%, lamellar bone, 38 ± 16.9% marrow space and 17.3 ± 13.2% deproteinized bovine bone were observed in the biopsies, with 61.5 ± 34% bovine bone to bone contact. Length and area of the particles did not differ significantly between 11 years and 6 months in the same patients.

Rossi F, Ricci E, Marchetti C, Lang NP, Botticelli D. Early loading of single crowns supported by 6-mm-long implants with a moderately rough surface: a prospective 2-year follow-up cohort study. Clin Oral Implants Res 2010;21(9):937-943.

A total of 40 implants (6 mm long and either 4.1 mm or 4.8 mm wide) were placed in 35 patients, and implant survival, marginal bone loss and resonance frequency analysis (RFA) measurements were performed. The implant survival rate was 95% (two implants lost) after 2 years, and mean marginal bone loss was 0.34 ± 0.38 mm before loading and 0.23 ± 0.33 mm and 0.21 ± 0.39 mm at 1 and 2 years, respectively. Implant stability increased from implant placement to 6 weeks and the crown/implant ratio decreased from 1.5 at prosthesis placement to 1.8 at 2 years. High implant survival and moderate bone loss was therefore observed after 2 years, but longer-term investigations are necessary  to assess the reliability of short implants.

Mordenfeld A, Hallman M, Johansson CB, Albrektsson T. Histological and histomorphometrical analyses of biopsies harvested 11 years after maxillary sinus floor augmentation with deproteinized bovine and autogenous bone. Clin Oral Implants Res 2010;21(9):961-970.

Thirty maxillary sinuses in 20 patients were augmented with 80% deproteinized bovine bone and 20% autogenous bone. Biopsies were taken from 11 patients after 11 years and evaluated. Mean 44.7 ± 16.9%, lamellar bone, 38 ± 16.9% marrow space and 17.3 ± 13.2% deproteinized bovine bone were observed in the biopsies, with 61.5 ± 34% bovine bone to bone contact. Length and area of the particles did not differ significantly between 11 years and 6 months in the same patients.

 

Danza M, Tortora P, Quaranta A, Perrotti V, Vozza I, Piattelli A. Randomised study for the 1-year crestal bone maintenance around modified diameter implants with different loading protocols: a radiographic evaluation. Clin Oral Investig 2010;14(4):417-426.

In 25 patients, 40 implants were placed and loaded either immediately (20  implants) or conventionally (20 implants). Bone level measurements were evaluated. No significant differences in bone loss between conventionally or immediately loaded implants were noted in the maxilla, but slight differences were noted in the mandible, where lower marginal bone loss was observed.

Harder S, Dimaczek B, Açil Y, Terheyden H, Freitag-Wolf S, Kern M. Molecular leakage at implant-abutment connection – in vitro investigation of tightness of  internal conical implant-abutment connection against endotoxin penetration. Clin Oral Investig 2010;14(4):427-432.

The inner parts of two different internal conical connection implants (Astra Tech and Ankylos; eight implants per system) were inoculated with endotoxin and abutments were screwed in place. The implants were then stored in pyogen-free water for 168 h, with samples  taken after 5 min, and 24, 72 and 168 h to evaluate endotoxin contamination. Contamination was observed after varying  storage times, and implants in the Ankylos group exhibited contamination after only 5 min. Only one implant (in the Astra Tech group) showed no signs of contamination after 168 h. The internal  conical connections tested therefore did not prevent endotoxin leakage.

European Journal of Oral Implantology

Vol. 3 No. 3 (September 2010)

Esposito M, Grusovin MG, Polyzos IP, Felice P, Worthington HV. Timing of implant placement after tooth extraction: immediate, immediate-delayed or delayed implants? A Cochrane systematic review. Eur J Oral Implantol 2010;3(3):189-205.

A systematic literature review was performed according to Cochrane criteria for randomized controlled trials of various implant placement protocols with at  least 1 year follow-up data and with outcomes including implant and prosthesis failures, complications, patient satisfaction, esthetics and marginal bone level changes. The search identified 14 trials, of which seven were included. Two studies comparing immediate versus delayed implants found no significant differences between the groups. In one trial comparing immediate-delayed versus delayed implants, perceived time to functional loading, patient satisfaction and judgment of the peri-implant mucosa was better with  immediate-delayed implants after 2 years, but there were no differences after 5 years. No significant differences between immediate and immediate-delayed implants were observed in one trial, and no significant differences were observed in three trials evaluating different bone grafting techniques. Evidence to determine the advantages of any implant placement protocol is therefore insufficient.

 

Capelli M, Esposito M, Zuffetti F,  Galli F, Del Fabbro M, Testori T.  A 5-year report from a muticentre randomised clinical trial: immediate non-occlusal versus early loading of dental implants in partially edentulous patients. Eur J Oral Implantol 2010;3(3):209-219.

Implants were placed in 52 patients and loaded either immediately (temporary restoration out of occlusion within 24 h; 52 implants in 25 patients) or early  (restoration placed after 2 months; 52 implants in 27 patients). One patient in the early loading group dropped out before the 1-year follow-up and one implant in the immediate loading group failed. Peri-implant bone loss and soft tissue changes were observed in both groups, but the differences between the groups were not significant. Significant recession of the vestibular soft tissues was observed after 5 years for immediate implants only.

Checchi L, Felice P, Antonini ES,  Cosci F, Pellegrino G, Esposito M.  Crestal sinus lift for implant rehabilitation: a randomised clinical trial comparing the Cosci and Summers techniques. A preliminary report on complications and patient preference. Eur J Oral Implantol 2010;3(3):221-232.

In 15 patients, crestal sinus lift was performed using the Cosci or Summers techniques with bone substitutes and 19 dental implants were placed for each technique and left to heal submerged. The implants were provisionally loaded after 6 months and definitive metal-ceramic restorations were placed after a further 4 months. There were no implant failures in either group. Discomfort was reported  in 12 patients with the Summers technique, with one case of sinus membrane perforation, but no discomfort or complications were reported with the Cosci technique. Implant placement  time was also significantly lower with the Cosci technique (24 versus 33 min). The Cosci technique  was preferred by 14/15  patients and by the two operators.

Badr M, Coulthard P, Alissa A, Oliver R.  The efficacy of platelet-rich  plasma in grafted maxillae. A randomised clinical trial. Eur J Oral Implantol 2010;3(3):233-234.

Onlay grafting in the maxilla was performed in 22 patients, of whom 16 also received sinus grafting with particulate bone. PRP was mixed with the bone grafts in 13 patients; nine patients received no PRP (control). There was one graft failure in the PRP group, requiring re-grafting. All implants were integrated, and soft tissue healing and graft resorption were not significantly different between the groups. Implant stability was similar at implant placement and exposure between the groups but was significantly higher for posterior implants in the PRP group versus anterior implants at implant placement, but this had no clinical significance. PRP therefore had no appreciable effect. 

European Journal of Oral Sciences

Vol. 118 No. 5 (October 2010)

Schley J-S, Heussen N, Reich S, Fischer J, Haselhuhn K, Wolfart S. Survival probability of zirconia-based fixed dental prostheses up to 5 yr: a systematic review of the literature. Eur J Oral Sci 2010;118(5):443-450.

A literature search was conducted by three reviewers to identify clinical studies with 5-year survival rates up of zirconia-based fixed dental prostheses. From an initial total of 399 articles, 18 were selected for full review, of which nine met the inclusion criteria. The articles included 310 three- to four-unit FDPs and 20 FDPs with > four units. Of these, 19 FDPs failed, giving a 5-year cumulative survival rate of 94.29%, while the 5-year complication-free rates were 76.41% and  91.72% for technical and biological complications, respectively. Chipping was the most frequent technical complication. Survival rates were therefore promising but improvements of the veneering systems are necessary.

Implant Dentistry

Vol. 19 No. 4 (August 2010)

Chan H-L, Misch K, Wang H-L. Dental imaging in implant treatment planning. Implant Dent 2010;29(4):288-298.

Literature on the use of imaging in dental implant treatment planning was searched, specifically focusing on medical CT and cone-beam CT (CBCT). Medical CT imaging was introduced for implant planning approximately 20 years ago, and can produce accurate, high-resolution 3D images. CBCT has advantages due to its specific design for the oral-maxillofacial region, lower radiation,  lower costs and image quality. Such 3D images may help the clinician to select appropriate implant dimensions and predict treatment outcomes.

Casado PL, Duarte MEL, Carvalho W,  Esmeraldo da Silva L, Barboza EP.  Ridge bone maintenance in human after extraction. Implant Dent 2010;29(4):314-322.

A total of 46 alveolar defects were filled with bovine BMP + bovine organic matrix (bOM), BMP + bOM + absorbable membrane (AM), AM alone, or were left unfilled. Ridge width was evaluated before treatment and after 4 months. All three test groups showed relevant ridge width augmentation, compared to no significant augmentation in the control group. Active bone formation with osteoid, osteoblasts and cell differentiation was observed in the test groups. BMP + bOM can therefore results in viable ridge formation, with or without absorbable membrane.

Turkyilmaz I. One-year clinical outcome of dental implants placed in patients with type 2 diabetes mellitus: a case series. Implant Dent 2010;29(4):323-329.

A total of 23 implants were placed in 10 patients with well-controlled or moderately well-controlled diabetes. No implant failures occurred up to 1 year, and the mean marginal bone loss was 0.3 ± 0.2 mm. No radiolucency, bleeding on probing or pathologic probing  depth was observed. The results indicated that dental implants may be successfully used in patients with well- or moderately well-controlled diabetes, with no significant complications.

Rabelo GD, de Paula PM, Rocha FS, Jordão Silva C, Zanetta-Barbosa D.  Retrospective study of bone grafting procedures before implant placement. Implant Dent 2010;29(4):342-350.

A total of 136 autogenous bone grafting procedures performed in 93 patients over a 7-year period were retrospectively evaluated. The most frequently used donor areas were the mandibular external oblique line and ascending ramus (59.64%), while block graft was  the most frequently used graft type (67.64%). The majority of procedures (75%) were in the maxilla, with fewer complications than those in the mandible; the most common complication was sinus mucosa perforation in the maxilla and graft exposure in the mandible. Alveolar reconstruction with autogenous bone with subsequent implant placement was found to be a reliable treatment option, but morbidity and complications were frequently observed.

 Manso M, Wassal T.  A_10-year longitudinal study of 160 implants simultaneously installed in severely atrophic posterior maxillas grafted with autogenous bone and a synthetic bioactive resorbable graft. Implant Dent 2010;29(4):351-360.

A total of 45 patients received sinus augmentation (in 57 sinuses with ≤ 4 mm of residual sub-sinus bone) with simultaneous placement of 160 implants in a modified technical and biomaterial protocol using composite autogenous bone with synthetic bioactive resorbable graft. The mean follow-up time was 61.7 months, and specific cases were followed up with  CT scans. Implant survival and success rates were 98.05% and 94.85%, respectively, indicating that the protocol may be a suitable approach for advanced posterior maxillary resorption.

 

International Journal of Oral and Maxillofacial Implants

Vol. 25 No. 4 (July/August 2010)

Yang G-L, He F-M, Song E, Hu J-A, Wang X-X, Zhao S-F. In vivo comparison of bone formation on titanium implant surfaces coated with biomimetically deposited calcium phosphate or electrochemically deposited hydroxyapatite. Int J Oral Maxillofac Implants 2010;25(4):669-680.

Implants coated with biomimetically deposited calcium phosphate (BDCaP) or electrochemically deposited hydroxyapatite (EDHA), or uncoated, were randomly placed in rabbit tibiae and evaluated after 2, 4 and 8 weeks. Analysis showed that the BDCaP coating comprised HA and octacalcium phosphate, whereas the EDHA coating comprised only HA. New bone on the EDHA-coated implants was mature after 4 weeks, whereas bone on the BDCaP-coated and control implants was mature after 8 weeks. BIC and bone area were also significantly greater for the EDHA-coated implants at 4 and 8 weeks. The EDHA coating therefore demonstrated good bone formation properties.

 Choi K-S, Lozada JL, Kan JY, Lee S-H, Kim C-S, Kwon T-G.  Study of an experimental microthreaded scalloped implant design: proximal bone healing at different interimplant distances in a canine model.  Int J Oral Maxillofac Implants 2010;25(4):681-689.

A total of 70 implants with a microthreaded scalloped design (35 implants) or a flat-top design (35 implants) were placed in the mandibles of 10 dogs; in five dogs,  four of each implant type were placed with an inter-implant distance of 2 mm and three implants of each type in the other five dogs were placed with an inter-implant distance of 5 mm. After 4 months, radiographic and histological analysis showed significantly less bone loss around the scalloped implants than the flat-top implants. No differences were observed between the implants placed at inter-implant distances of 2 or 5 mm for either implant type. The microthreaded scalloped implants were therefore more effective at preserving proximal bone.

 

Gallego L, Junquera L, Meana Á, García E, García V.  Three-dimensional culture of mandibular human osteoblasts on a novel albumin scaffold: growth, proliferation, and differentiation potential in vitro. Int J Oral Maxillofac Implants 2010;25(4):699-705.

Osteoblast cells obtained from mandibular bone were cultured in a protein scaffold prepared with plasmatic albumin and glutaraldehyde-type agent (test) or mineralized cancellous allograft (control). After 90 days, alkaline phosphatase was expressed by cells in the albumin scaffold. Bone-like extracellular matrix was observed in the study scaffold and mineralization of osteoblasts was seen in the albumin scaffold. Osteoblast proliferation in the albumin scaffold was therefore confirmed.

 Urdaneta RA, Rodriguez S, McNeil C, Weed M, Chuang S-K. The effect of increased crown-to-implant ratio on single-tooth locking-taper implants. Int J Oral Maxillofac Implants 2010;25(4):729-743.

A cohort of 81 patients who received 326 single-tooth implants and cementless restorations were retrospectively evaluated. The mean follow-up time was 70.7 months and the mean change in mesiodistal bone level was -0.33 mm. The mean crown-to-implant ratio (C/IR) was 1.6, and C/IR ≥ 2.0 was observed in 16% of restorations; these were more likely to have increased crown width, larger implant diameter, larger mesial/distal distance to adjacent structures and deeper sulcular probing. Loosening of maxillary anterior abutment crowns was significantly  influenced by increased C/IR, but the risk of crestal bone loss was not increased by a C/IR up to 4.95.

Lee FK, Tan KB, Nicholls JI. Critical bending moment of four implant-abutment interface designs. Int J Oral Maxillofac Implants 2010;25(4):744-751.

Critical bending moment was measured in vitro for four implant-abutment types (Bränemark/CeraOne, Nobel Replace/Easy, Biomet 3i/STA and Lifecore/COC) at 80%, 100% and 120% of the manufacturers’ recommended torque levels. Loads were applied and microstrains were measured while know loads were applied. Mean crestal bending moment at 100% of the recommended torque was 102.21 Ncm, 109.92 Ncm, 83.14 Ncm and 76.79 Ncm for Bränemark-CeraOne, Nobel Replace/Easy, Biomet 3i7STA and Lifecore/COC assemblies, respectively; significant differences between groups and torque levels were noted. Compressive preload by the abutment screw appears to play a key role in maintaining screw joint integrity.

Chua J-Y, Takano-Yamamoto T, Hwang C-J. Effect of miniscrew taper morphology on insertion and removal torque in dogs. Int J Oral Maxillofac Implants 2010;25(4):777-783.

In six dogs, 48 miniscrews were placed with maximum insertion torque, with removal torque assessed after 3 and 12 weeks. A further 48 implants were inserted in  almost the same places as those removed, and insertion torque and 3- and 12-week removal torque were recorded once more. Histological analysis was also performed. Mean maximum insertion torque was  significantly greater with tapered miniscrews than cylindrical miniscrews, and mean maximum removal torque was significantly greater at 3 weeks but not at 12 weeks. BIC was similar between the groups at 3 weeks, and bone volume/total volume was significantly greater for the tapered miniscrews at 3 weeks. The tapered design therefore increased initial stability but did not influence secondary stability.

Liao K-Y, Kan JY, Rungcharassaeng K,  Lozada JL, Herford AS, Goodacre CJ.  Immediate loading of two freestanding implants retaining a mandibular overdenture: 1-year pilot prospective study.  Int J Oral Maxillofac Implants 2010;25(4):784-790.

Ten patients each received two freestanding implants to support a mandibular removable overdenture. Implant success and marginal bone levels were recorded after 1 year. Two patients, one with one implant failure, dropped out of the study. The mean marginal bone loss was 1.12 ± 1.10 mm and the cumulative implant success rate was 94%. However, if bone  loss above the smooth-rough  implant surface was considered, the mean bone loss was 0.73 mm. Osseointegration was confirmed by Periotest, and no irreversible prosthetic or surgical complications were noted. Two immediately loaded unsplinted implants retaining a mandibular overdenture was therefore a suitable treatment approach.

Brennan M, Houston F, O’Sullivan M, O’Connell B. Patient satisfaction and oral health-related quality of life outcomes of implant overdentures and fixed complete dentures.  Int J Oral Maxillofac Implants 2010;25(4):791-800.

A population of 62 patients who had received implant-supported overdentures or complete implant fixed prostheses were identified to assess oral health-related quality of life (via the Oral Health Impact Profile-14 tool) and patient satisfaction (via a  survey). Patient satisfaction was  high in both prosthetic groups, but satisfaction with cost, treating doctor and the ability to perform oral hygiene were lower in the fixed prosthesis group, and satisfaction with chewing capacity, with esthetics, and overall, was significantly lower in the overdenture group. Oral health-related quality of life was high, but psychological discomfort and disability were significantly lower in the fixed prosthesis group. Patients with an overdenture were therefore generally less satisfied and had lower oral health-related quality of life than those with a fixed prosthesis.

Merli M, Lombardini F, Esposito M. Vertical ridge augmentation with autogenous bone grafts 3 years after loading: resorbable barriers versus titanium-reinforced barriers. A randomized controlled clinical trial.  Int J Oral Maxillofac Implants 2010;25(4):801-807.

Vertical bone augmentation was performed with autogenous bone grafts in 22 patients; half of the patients received a resorbable collagen barrier supported by an  osteosynthesis plate, while half received a non-resorbable ePTFE barrier. Follow-up times ranged from provisional loading to 3 years post-loading. There were no prosthetic or implant failures. Peri-implant bone loss was significant, but there was no significant difference in bone loss between the groups at 1 and 3 years (mean bone loss 0.55 mm and 0.53 mm for resorbable and non-resorbable barriers, respectively, at 3 years).

International Journal of Periodontics and Restorative Dentistry

Vol. 30 No. 4 (July/August)

Su H, González-Martin O, Weisgold A, Lee E. Considerations of implant abutment and crown contour: critical contour and subcritical contour. Int J Periodontics Restorative Dent 2010;30(4):335-343.

The implant abutment can be used to effect the transition from the circumferential design of the implant head to the design of the tooth anatomy. Overcontouring of the abutment can cause apical positioning of the gingival margin and undercontouring has the opposite effect, but the concept of ‘contouring’ as it applies to implant dentistry should be re-defined. Two zones in  the abutment and crown the critical and subcritical contour, can modify the soft tissue profile. The effect of modifications at these zones was therefore investigated.

Blus C, Szmukler-Moncler S.  Atraumatic tooth extraction and immediate implant placement with piezosurgery: evaluation of 40 sites after at least 1 year of loading.  Int J Periodontics Restorative Dent 2010;30(4):355-363.

A total of 40 teeth were extracted in 23 patients and immediately replaced with implants. The fibers of the periodontal ligament were cut using piezosurgery  and the teeth/roots mobilized and removed without fracture. Notching of the apical third of the palatal wall was made during implant placement, or interradicular bridge was performed with no complications. All implants were osseointegrated and successful for up to 12 months. Extraction by piezosurgery can therefore be atraumatic, with predictable subsequent implant placement.

McAllister BS, Haghighat K, Prasad HS, Rohrer MD. Histologic evaluation of recombinant human platelet-derived growth factor-BB after use in extraction socket defects: a case series.  Int J Periodontics Restorative Dent 2010;30(4):365-373.

Twelve extraction sockets were treated with either β-tricalcium phosphate or anorganic deproteinized bovine bone, both with 0.3 mg/mL rhPDGF-BB. Histologic evaluation after 3 months of uneventful socket healing showed similar results in both groups (21% and 24% vital bone in the  β-TCP and bovine bone groups, respectively). Implants were placed without the need for further grafting, and the subsequent implant success rate was 100%.

 

Larsson C, von Steyern PV, Nilner K.  A prospective study of implant-supported full-arch yttria-stabilized tetragonal zirconia polycrystal mandibular fixed dental prostheses: three-year results.  Int J Prosthodont 2010;23(4):364-369.

Implant-supported Y-TZP fixed prostheses, fabricated according to the Cercon technique, were placed in 10 patients; nine patients received 10-unit FDPs while one received a nine-unit FDP. Assessments were made at baseline and after 1, 2 and 3 years. All FDPs were in function after 3 years and all patients were satisfied with their prosthesis. There were no prosthesis fractures but superficial chipping of the veneering porcelain was found for 34 of the 99 units. The results suggested that Cercon-manufactured Y-TZP FDPs should be regarded cautiously as a treatment option.

Journal of Clinical Periodontology

Vol. 37 No. 9 (September 2010)

Vol. 37 No. 10 (October 2010)

Schliephake H, Hefti T, Schlottig F, Gédet P, Staedt H.  Mechanical anchorage and peri-implant bone formation of surface-modified zirconia in minipigs. J Clin Periodontol 2010;37(9):818-828.

Three types of implants (zirconia sandblasted, zirconia sandblasted and acid-etched or titanium sandblasted acid-etched) were placed in the mandibles of 12 minipigs 8 weeks after tooth removal. Removal torque and peri-implant bone were examined after 4 and 13 weeks. There were no significant differences in mean BIC between the groups at 4 weeks, but mean BIC was significantly higher for the titanium implants after 13 weeks. Removal torque was also significantly higher for the titanium implants at 4 and 13 weeks. No significant differences in bone volume density were noted between the groups. The higher removal torques with titanium implants may be due to the higher surface roughness with these implants.

Graziani F, Cei S, Tonetti M, Paolantonio M, Serio R, Sammartino G, Gabriele M, D’Aiuto F.  Systemic inflammation following non-surgical and surgical periodontal therapy.  J Clin Periodontol 2010;37(9):848-854.

Non-surgical periodontal treatment was carried out in 14 patients with chronic periodontitis, and at least two sessions of surgical therapy were performed after 6 months. Blood samples were obtained and evaluated for systemic inflammation/coagulation. The number of periodontal pockets, amount of gingival bleeding and plaque were reduced after 3 and 6 months following non-surgical therapy, and there was a significant further reduction in periodontal pockets following surgical therapy. CRP and serum amyloid-A were significantly increased 24 hours after both non-surgical and surgical  therapy, with a greater increase in CRP after non-surgical therapy. A significant increase in D-dimer levels was also observed following non-surgical therapy. Perturbations of systemic inflammation were therefore greater after non-surgical periodontal therapy.

Tsakos G, Bernabé E, D’Aiuto F, Pikhart H, Tonetti M, Sheiham A, Donos N.  Assessing the minimally important difference in the Oral Impact on Daily Performance index in patients treated for periodontitis. J Clin Periodontol 2010;37(10):903-909.

The Oral Impact on Daily Performance (OIDP) index  was assessed in a total of 45 patients receiving intensive (17 patients) or conservative (28 patients) periodontal care at baseline and 1 months after treatment. The minimally important difference (MID) was estimated and the effect size was calculated. Mean OIDP score was significantly lower after 1 month, indicating an improvement in quality of life, but there were no differences between the groups. The MID was estimated at approximately five scale points, corresponding to a moderate effect size.

Listl S, Tu Y-K, Faggion CM Jr. A cost-effectiveness evaluation of enamel matrix derivatives alone or in conjunction with regenerative devices in the treatment of periodontal intra-osseous defects.  J Clin Periodontol 2010;37(10):920-927.

Costs and clinical outcomes of EMD treatments were assessed using a decision tree model based on insurance regulations. EMD treatment was judged to be more cost-effective if willingness-to-pay was at least €150-175 per incremental mm of reduction in probing depth or gain in clinical attachment level. Maximum net benefit of EMD was found with EMD in conjunction with bioactive glass or bovine bone substitutes, and the additional use of PRP or a resorbable membrane was justifiable only in cases of higher monetary resources.

Krennmair G, Seemann R, Piehslinger E.  Dental implants in patients with rheumatoid arthritis: clinical outcome and peri-implant findings. J Clin Periodontol 2010;37(10):928-936.

Implant survival and success, peri-implant conditions and prosthodontic maintenance were recorded in 34 female patients with rheumatoid arthritis (RA), with  or without connective tissue disease (CTD). Implant survival and success were 100% and 93.8%, respectively over a mean 47.6 month follow-up, and there was no difference between those with RA and RA + CTD. Increased bone resorption and more vulnerable soft tissue conditions was noted in patients with RA +  CTD, and peri-implant parameters were found to be significantly influenced by the underlying disease.

Blanco J, Liñares A, Villaverde G, Pérez J, Muñoz P. Flapless immediate implant placement with or without immediate loading: a histomorphometric study in beagle dog. J Clin Periodontol 2010;37(10):937-942.

Each of six dogs received two implants on each side of the mandible immediately after tooth extraction. One implant was placed with a flapless immediate procedure; the same procedure was carried out on the contralateral side with an immediate prosthesis placed in occlusal contact. No implants or prostheses were lost after 3 months, and there was no significant difference in mean BIC, inter-thread bone area or peri-implant bone between the groups. Similar osseointegration can therefore be achieved with flapless immediate implant placement as with immediate placement without loading.

Journal of Cranio-Maxillofacial Surgery

Vol. 38 No. 7 (October 2010)

Nickenig H-J, Wichmann M, Hamel J, Schlegel KA, Eitner S.  Evaluation of the difference in accuracy between implant placement by virtual planning data and surgical guide templates versus the conventional free-hand method – a combined in vivo-in vitro technique using cone-beam CT (Part II). J Cranio-Maxillofac Surg 2010;38(7):488-493.

In 10 patients, 23 patients were placed with a 3D planned surgical guide template, and manual implantation was performed using casts of the same patients. Images of the casts were subsequently superimposed onto the virtual planned ideal implant positions. Significantly smaller variation between planned and actual position was found with the 3D surgical guide compared to freehand implant placement, and the accuracy of axis was also significantly improved. Implant positioning with cone-beam CT data and surgical templates is therefore more accurate than freehand implant placement.

 

Stockmann P, Böhm H, Driemel O, Mühling J, Pistner H. Resorbable versus titanium osteosynthesis devices in bilateral sagittal split ramus osteotomy of the mandible – the results of a two-centre randomised clinical study with an eight-year follow-up. J Cranio-Maxillofac Surg 2010;38(7):522-528.

Bilateral sagittal split ramus osteotomy was performed in 66 patients with isolated mandibular jaw disproportion. Fixation was with resorbable lactic acid containing positioning screws or with titanium positioning screws. A total of 34 patients were followed until the end of the study at 8 years. Outcomes were not significantly different between those with resorbable or titanium screws, and no foreign body reactions were observed. Resorbable and titanium screws were therefore equally effective as fixation devices.

Journal of Dental Research

Vol. 89 No. 9 (September 2010)

Kebschull M, Demmer RT, Papapanou PN.  ”Gum bug, leave my heart alone” – epidemiologic and mechanistic evidence linking periodontal infections and atherosclerosis. J Dent Res 2010;89(9):879-.

 Modest but consistent epidemiological data suggest  an association between periodontal infections and atherosclerotic vascular disease. Data also suggest  that periodontal treatment has a favorable effect on subclinical markers of atherosclerosis. Mechanistic studies have suggested possible pathways for these effects, although the models are mostly mono-infections by a limited number of periodontal pathogens and may not portray the complexity of periodontitis. Future research should therefore  identify the pathways that lead to atherogenesis and those that may reduce atherosclerosis risk.

Journal of Oral and Maxillofacial Surgery

Vol. 68 No. 9 (September 2010)

Vol. 68 No. 10 (October 2010)

Linkevicius T, Apse P, Grybauskas S, Puisys A.  Influence of thin mucosal tissues on crestal bone stability around implants with platform switching. J Oral Maxillofac Surg 2010;68(9):2272-2277.

Twelve implants, either platform-switched (test) or with matching implant-abutment diameters (control), were placed in four patients in sites with ≤ 2 mm mucosal tissue. Mean mesial and distal bone loss after 1 year was 1.81 ± 0.39 mm and 1.70 ± 0.35 mm, respectively, for test and 1.60 ± 0.46 mm and 1.76 ± 0.45 mm, respectively, for control implants. Platform-switched implants therefore did not appear to show better crestal bone preservation compared to implants with a matching  abutment diameter in the case of thin mucosal tissues.

Sohn D-S, Lee H-J, Heo J-U, Moon  J-W, Park I-S, Romanos GE.  Immediate and delayed lateral ridge expansion technique in the atrophic posterior mandibular ridge. J Oral Maxillofac Surg 2010;68(9):2283-2290.

Narrow edentulous posterior ridges in 32 patients were expanded using either an immediate lateral (23 patients) or a delayed lateral (nine patients) expansion technique, and a  total of 84 implants were placed. Malfracture of the buccal cortical plate occurred during ridge splitting  in five patients who received the immediate technique, but all buccal segments fractured as planned at the inferior horizontal corticotomy line in the nine patients who received the delayed technique. Both techniques were considered effective, but the delayed technique may be more safe and predictable.

Rousseau P. Flapless and traditional dental implant surgery: an open, retrospective comparative study. J Oral Maxillofac Surg 2010;68(9):2299-2306.

Implant placement was performed with either a flapless surgical approach in 121 patients (174 implants) or a traditional surgical approach in 98 patients (203 implants). There were three implant failures in each group, giving implant survival rates of 98.3% and 98.5% for the flapless and traditional surgical groups, respectively. The flapless approach can therefore be a predictable procedure comparable to traditional surgery, with benefits for the patient.

Journal of Oral Implantology

Vol. 36 No. 4 (August 2010)

Malchiodi L, Corrocher G, Cucchi A, Ghensi P, Bissolotti G, Nocini PF.  Long-term results of immediately loaded fast bone regeneration-coated implants placed  in fresh extraction sites in the upper jaw.  J Oral Implantol 2010;36(4):251-261.

A total of 158 fast bone regeneration-coated implants were placed in fresh extraction sockets in 70 patients, and prostheses were immediately placed. Implant success and survival and clinical and radiographic parameters were evaluated after 3 and 5 years. Cumulative implant success after 5 years was 98.7% (two implants lost), and hard and soft tissue were well maintained. The use of fast bone regeneration-coated implants is therefore predictable with careful case selection.

Ahn S-J, Leesungbok R, Lee S-W.  Histomorphometric analysis and removal torque of small diameter implants with alternative surface treatments and different designs. J Oral Implantol 2010;36(4):263-272.

 Implants were placed in rabbit tibia according to six different groups: machined; resorbable blast media (RBM)-treated; machined with a vertical groove; RBM with a vertical groove; RBM with an upper thread vertical groove; or, RBM with a lower trunk vertical groove. Removal torque, BIC and bone area rate were significantly higher with the RBM implants with vertical grooves than the machined implants. 

Luongo G, Oteri G.  A noninterventional study documenting use and success of implants with a new chemically modified titanium surface in daily dental practice. J Oral Implantol 2010;36(4):305-314.

A total of 226 patients were treated in 30 clinical centers using implants with a chemically modified SLA titanium surface according to the daily dental practice procedures applied by each of the investigators. Individuals with risk factors such as smoking, bruxism and untreated gingivitis/periodontitis were included. Most implants (48%) were placed with a early functional loading protocol, while conventional loading was applied in 34% of patients. Eight patients were lost to follow-up. Of the 276 implants placed, five failed, all of which were associated with a sinus augmentation procedure. Implant survival  after 1 year was 98.2%, indicating similar results to those from formal controlled clinical trials.

 

Romanos GE, Froum S, Hery C, Cho S-C, Tarnow D. Survival of immediately vs delayed loaded implants: analysis of the current literature. J Oral Implantol 2010;36(4):315-324.

Immediate loading of implants may be beneficial, but documentation is poor. A literature search was therefore performed to assess the survival rates of immediately loaded implants and to evaluate the available histological and histomorphometric analyses. High survival rates and high percentages of BIC were reported in both human and animal studies.

Journal of Oral Rehabilitation

Vol. 37 No. 9 (September 2010)

Nissan J, Ghelfan O, Gross M, Chaushu G. Analysis of load transfer and stress distribution by splinted and unsplinted implant-supported fixed cemented restorations. J Oral Rehabil 2010;37(9):658-662.

Implants were inserted into three holes in a photo-elastic model and two combinations of fabrications (three adjacent unsplinted crowns or three adjacent splinted crowns) were fabricated. Axial static 20 kg loading was performed and the resulting strains measured. Significantly more strain at the  implant neck was observed with the splinted restoration, but significantly more strain at the crown restoration margin was observed with the unsplinted crowns. The concept of splinting to decrease strain should therefore be re-evaluated.

 

Journal of Periodontal and Implant Science

Vol. 40 No. 4 (August 2010)

Cho H-L, Lee J-K, Um H-S, Chang B-S. Esthetic evaluation of maxillary single-tooth implants in the esthetic zone. J Periodontal Implant Sci 2010;40(4):188-193.

Pink and white esthetic scores (PES and WES) were evaluated for 41 patients who received a single implant in the esthetic zone; evaluations were performed by two periodontists, two prosthodontists, two orthodontists and two senior dental students twice, with an interval of 4 weeks between evaluations. Patient satisfaction was also assessed. Good intra-observer agreements were noted for PES and moderate agreements were noted for WES. Differences in scores were not significant for total PES/WES, but there were significant differences for WES, with poorer ratings noted for prosthodontists and higher ratings noted for periodontists. Orthodontists were found to be more critical than the other groups. There was a significant correlation between the esthetic perceptions of patients and dentists for anterior teeth but not for first premolars.

Journal of Periodontology

Vol. 81 No. 8 (August 2010)

Vol. 81 No. 9 (September 2010)

McGuire MK, Scheyer ET.  Xenogeneic collagen matrix with coronally advanced flap for the treatment of dehiscence-type recession defects. J Periodontol 2010;81(8):1108-1117.

Recession-type defects in 25 subjects were treated with either connective tissue graft (CTG; control) or collagen matrix (CM; test), both in combination with coronally advanced flap (CAF) and evaluated after 6 and 12 months. After 6 months, mean recession depth was 0.52 mm and 0.10 mm for test and control sites, respectively; the change from baseline was significant in both groups. Percentage root coverage after 12 months was 88.5% and 99.3% for test and control sites, respectively; the difference was not significant. Similarly, there were no significant differences between the groups in terms of esthetic satisfaction or subjects’ assessment of pain or discomfort. CM + CAF is therefore a viable alternative to CTG + CAF, but without morbidity associated with soft tissue graft harvest.

 

Crespi R, Capparè P, Gherlone E. Immediate loading of dental implants placed in periodontally infected and non-infected sites: a 4-year follow-up clinical study. J Periodontol 2010;81(8):1140-1146.

A total of 275 implants (197 in infected sites and 78  in non-infected sites) were placed and immediately loaded in 37 patients. Marginal bone levels were  evaluated at baseline and after 12, 24 and 48 months. Implant survival after 48 months was 98.9% (two implants lost) in  the infected group and 100% in the non-infected group. Marginal bone level was 0.79 ±  0.38 mm and 0.78 ± 0.38 mm for the infected and non-infected groups, and there were no significant differences between the groups for plaque accumulation and bleeding index. Implants placed in infected sites therefore showed no significant differences to those placed in non-infected sites.  

Chaushu G, Vered M, Mardinger O, Nissan J.  Histomorphometric analysis after maxillary sinus floor augmentation using cancellous bone-block autograft. J Periodontol 2010;81(8):1147-1152.

Sinus augmentation using cancellous bone-block allograft with simultaneous implant placement (76 implants) was performed in 31 patients, with second-stage surgery performed after 9 months. A total of 94.7% (72 implants) were clinically osseointegrated after this time. There was 26.1 ± 15% mean newly formed bone, 24.7 ± 19.4% residual graft and 49.2 ± 20.4% marrow and connective tissue. There were no significant differences in newly formed bone with respect to gender, age, presence of membrane perforations or residual alveolar ridge height. The material was  therefore biocompatible and osteocondictive and allows bone formation with simultaneous implant placement.  

Kauvar AS, Thoma DS, Carnes DL, Cochran DL.  In vivo angiogenic activity of enamel matrix derivative. J Periodontol 2010;81(8):1196-1201.

Various amounts of enamel matrix derivative (EMD) were placed onto the surface of a chorioallantoic membrane and compared to recombinant human amelogenin and a purified 5-kDa protein factor obtained from EMD, and bFGF/VEGF as a positive control. Histologic analysis showed moderate vascularity with EMD that compared favorably to that of bFGF/VEGF. Vascularity was also increased by recombinant human amelogenin, but the negative control produced only mild vascularity. EMD therefore stimulated angiogenesis in this model, which may partly explain its positive clinical effects.

Koo K-T, Wikesjö UME, Park J-Y, Kim T-I, Seol Y-J, Ku Y, Rhyu I-C, Chung C-P, Lee Y-M. Evaluation of single-tooth implants in the second molar region: a 5-year life-table analysis of a retrospective study.  J Periodontol 2010;81(9):1242-1249.

A total of 489 patients received 521 single-tooth implants in the second molar region (227 and 294 implants in the maxilla and mandible, respectively) over a 5-year period. The 1- to 5-year cumulative survival rate was 95.1%, and no significant differences were found between  implants placed in the maxilla versus mandible, one- versus two-stage implants, short versus long implants, or standard  versus wide diameter implants. Single-tooth implant placement in the second molar region was therefore an effective and reliable treatment modality.

Trombelli L, Simonelli A, Pramstraller M, Wikesjö UME, Farina R.  Single flap approach with and without guided tissue regeneration and a hydroxyapatite biomaterial in the management of intraosseous periodontal defects. J Periodontol 2010;81(9):1256-1263.

In 24 patients, single intra-osseous defects were treated with either single flap approach (SFA) alone or in combination with hydroxyapatite and guided tissue regeneration (HA/GTR) and assessed after 6 months. Incomplete closure was observed in five SFA + HA/GTR sites after 2 weeks, which spontaneously resolved. After 6 months, no significant differences in clinical attachment level gain, probing depth reduction or increase in gingival recession were observed between the SFA and SFA + HA/GTR groups. SFA is therefore a viable minimally invasive approach for the treatment of periodontal osseous defects.

Nampo T, Watahiki J, Enomoto A, Taguchi T, Ono M, Nakano H, Yamamoto G, Irie T, Tachikawa T, Maki K. A new method for alveolar bone repair using  extracted teeth for the graft material.  J Periodontol 2010;81(9):1264-1272.

The potential of using teeth as graft material, as the dental pulp contains stem cells, was investigated. Alveolar defects in rats were created and treated with either tooth or iliac bone graft material, or left untreated (control). P75, P0, nestin and musashi-1 expression were significantly higher in  the tooth grafts than the bone grafts or mandibular bone, and the tooth graft produced a similar amount of bone to iliac bone graft. Osteopontin was expressed in both graft materials after 6 and 8 weeks, while dental sialoprotein was only expressed in the tooth graft after 6 weeks. Teeth may therefore be a suitable alternative to autogenous bone in alveolar bone defects. 

Journal of Prosthodontics

Vol. 19 No. 6 (August 2010)

Rossetti PHO, Bonachela WC, Rossetti LMN.  Relevant anatomic and biomechanical studies for implant possibilities on the atrophic maxilla: critical appraisal and literature review. J Prosthodont 2010;19(6):449-457.

A literature review was performed on anatomic and biomechanical aspects of the atrophic maxilla for implant possibilities. Some of the key findings from the literature included the following: previous use of a removable prosthesis is a risk factor for resorption; implant supporting overdentures in the reconstructed maxilla had a higher risk for bone loss; prevalence of bone septa is higher in the atrophic maxilla; splinted implants receive much less load than unsplinted implants;  in vivo force transfer is similar between overdentures and fixed prostheses; and chewing efficiency and  bite force is improved in maxillectomized patients with obturators and milled bar attachments.

Park J-K, Choi J-U, Jeon Y-C, Choi K-S, Jeong C-M. Effects of abutment screw coating on implant preload. J Prosthodont 2010;19(6):458-464.

Abutment screws coated with tungsten carbide carbon were compared with non-coated titanium alloy screws by evaluating preloads in tightening rotational angle,  compression force, initial screw removal torque and post-load torque after 1 million cycles. Rotational angle was 10° higher for coated screws in all abutment systems, and compression force was higher with external hex connections than internal connections. Compression force was also significantly higher for the coated screws, while removal torque was significantly lower and post-load removal torque was significantly higher. Coated screws were superior in maintaining preload.

Journal of the American Dental Association

Vol. 141 No. 10 (October 2010)

Greenstein G, Cavallaro J Jr. Cantilevers extending from unilateral implant-supported fixed prostheses.  J Am Dent Assoc 2010;141(10):1221-1230.

A literature search was performed for studies evaluating the survival rates and complications associated with implant-supported cantilevered FDPs. Five-year data  were considered most suitable to evaluate the effectiveness of implant therapy, but shorter follow-up periods were included due to the scarcity of 5-year data. The estimated 5-year survival rate for short-span cantilevered prostheses was 94.3%, but these prostheses may be associated with technical problems that do not result in failure. Implant-supported cantilevered FDPs can therefore be  used in positions were placement of a dental implant may not be suitable.

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology

Vol. 110 No. 3 (September 2010)

Vol. 110 No. 4 (October 2010)

Kim Y-K, Park J-Y, Kim S-G, Lee H-J.  Prognosis of the implants replaced after removal of failed dental implants. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110(3):281-286.

A total of 49 patients who had experienced implant failure and subsequently received a second implant were retrospectively evaluated. The maxillary first molar area was the most frequent failure site, and the second implant was placed immediately in 48.3% of cases and delayed in 51.7% of cases; there was no difference in failure rate between the two. The failure rate for second implants was 11.7%; a third implant was placed in each of these cases. Mean marginal bone loss at the final follow-up was 0.33 ± 0.49 mm.

 

Lee H-J, Kim Y-K, Park J-Y, Kim S-G, Kim M-J, Yun P-L. Short-term clinical retrospective study of implants in geriatric patients older than 70 years.  Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110(4):442-446.

A total of 35 patients over 70 years of age who received implant treatment over a 3-year period were evaluated. Mean peri-implant bone resorption after a mean period of 32.7 months was 0.27 mm and did not appear to be significantly related to type of prosthesis, surgical procedures or systemic disease. Implant therapy in geriatric patients was therefore not considered to be high-risk.

Quintessence International

Vol. 41 No. 8 (September 2010)

Vol. 41 No. 9 (October 2010)

Beuer F, Stimmelmayr M, Gernet W, Edelhoff D, Güth J-F, Naumann M. Prospective study of zirconia-based restorations: 3-year clinical results. Quintessence Int 2010;41(8):631-637.

FDPs and single crowns with CAD/CAM-fabricated substructures were placed in 38 patients (18 FDPs and 50 single crowns) and evaluated at baseline (2 weeks) and after 12, 24 and 36 months. Mean time in service was 35 ± 14 months. Survival probability was 88.2% after 35 months for all failure types and 98.5% for restorations in service. Eight failures were recorded, three biological and five technical, all of which occurred in the FDP group. The type of restoration therefore had a significant influence on the probability of survival.

Degidi M, Nardi D, Piattelli A. Immediate definitive rehabilitation of the edentulous patient using an intraorally welded titanium framework: a 3-year prospective study. Quintessence Int 2010;41(8):651-659.

A total of 26 patients with an edentulous maxilla and 34 patients with an edentulous mandible received 324 implants immediately loaded with fixed restorations supported by an intraorally welded titanium bar. Implant success, marginal bone loss and periodontal parameters were evaluated over 36 months. No fractures or framework alterations were detected. At 6 months 321 implants (99.1%) were  clinically stable. Mean marginal bone loss after 36 months was 0.967 ± 0.361 mm in the maxilla and 1.016 ± 0.413 mm in the mandible. Edentulous patients can therefore be successfully rehabilitated with a definitive prosthesis on the day of surgery.  

Szentpétery V, Lautenschläger C, Setz JM. Longevity of frictional crowns in  the severely reduced dentition: 3-year results of a longitudinal prospective clinical study. Quintessence Int 2010;41(9):749-758.

A total of 82 telescopic removable partial dentures retained by 173 frictional telescopic crowns were placed in 74 patients with severely reduced dentitions and re-examined after 1 week and 3, 6, 12, 18, 24, 30 and 36 months. the survival rates of abutment teeth and telescopes were 93.9% and 87.5%, respectively, and were influenced by number of telescopes, abutment distribution, vitality and gender. Risk of telescope loss was also affected by these factors. Telescopic removable partial dentures can therefore be a favorable treatment concept for severely reduced dentition.

 

Tissue Engineering Part B: Reviews

Vol. 16 No. 5 (October 2010)

Klijn RJ, Meijer GJ, Bronkhorst EM, Jansen JA.  A meta-analysis of histomorphometric results and graft healing time of various biomaterials compared to autologous bone used as sinus floor augmentation material in humans. Tiss Eng B Rev 2010;16(5):493-507.

A meta-analysis of studies that included histomorphometric data from biomaterials in sinus augmentation was performed. From an initial total of 147 articles, 64 were included in the meta-analysis. The reference value for total bone volume was 63%, based on autologous bone grafting. Total bone volume is reduced by approximately 18% with particulation of then bone graft and by approximately 7% with delayed implant placement, but bone volume was higher if a biopsy was taken after 4.5 or 9 months. Total bone volume was significantly lower (by 7 to 26%) with the use of allogenic, xenogenic or alloplastic materials or combinations thereof. Biopsy time had no significant influence of total bone volume for bone substitutes.


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