A randomized, controlled clinical evaluation of a synthetic gel membrane for guided bone regeneration around dental implants: clinical and radiologic 1-and 3-year results

PURPOSE: The objective of this study was to determine whether a synthetic bioresorbable polyethylene glycol (PEG) hydrogel membrane could provide similar clinical and radiographic outcomes as a standard collagen membrane, both in combination with a membrane-supporting material, during follow-up periods of 1 and 3 years. MATERIALS AND METHODS: This study enrolled patients requiring implant treatment with an expected osseous defect in the posterior maxilla or mandible. Defects around the implants were grafted with deproteinized bovine bone mineral and covered with either a collagen membrane or a PEG hydrogel membrane, which is applied as a liquid and becomes a solid gel in situ. Surgical re-entry was performed after 6 months, and fixed partial dentures were inserted subsequently. Patients were examined clinically and radiographically 1 and 3 years after loading. RESULTS: Thirty-six of the 37 included patients were reexamined in the third year. The implant survival rate at 3 years was 100%. The peri-implant tissues were healthy, with no differences between the two groups. Compared to the time of surgery, the mean changes in the distance between the first bone-to-implant contact to the transition point (ie, rough implant surface to polished neck portion) were 0.43 ± 0.56 mm (PEG) and 0.21 ± 0.36 mm (collagen) at 1 year and 0.61 ± 0.89 mm (PEG) and 0.33 ± 0.64 mm (collagen) at 3 years. The respective differences between groups were 0.13 mm (1 year) and 0.31 mm (3 years), which were not significant at either time point (analysis of covariance). CONCLUSION: The tested PEG hydrogel was as successful as a standard collagen membrane for the treatment of bony dehiscence defects around dental implants after follow-up periods of 1 and 3 years

Effect of Thermomechanical Loading on the Cementation Interface of Implant-Supported CAD/CAM Crowns Luted to Titanium Abutments

Purpose: To investigate the effect of aging on the morphology of the interface between monolithic implant crowns and standardized titanium base abutments. Materials and Methods: Four groups of hybrid abutment crowns differing in restorative material (lithium disilicate [LD] or polymer-infiltrated ceramic network [PICN]) and in fabrication procedure of the interfacial zone for luting to a titanium abutment (milled during CAD/ CAM procedure [M] or prefabricated [P]) were formed: LDS-M, LDS-P, PICN-M, and PICN-P (n = 10 each). The morphology of the crown-abutment interface was examined before and after artificial aging using scanning electron microscopy. The total gap length per specimen was measured at both time points, and intergroup (Kruskal-Wallis [KW]) plus pairwise (Wilcoxon Mann-Whitney [WMW]) comparisons were performed (α =. 05). Results: Before aging, statistically significant differences in gap length were identified among groups (KW: P=. 0369) for PICN-P > LDS-P (WMW: P=. 0496) and LDS-M > LDS-P (WMW: P=. 0060). The effect of aging among the groups, expressed as an increment of total gap length, was 50% in LDS-M, 30% in LDS-P, 20% in PICN-M, and 30% in PICN-P. After aging, the statistically significant differences in gap length identified among groups (KW: P=. 0048) were for PICN-P > LDS-P (WMW: P=. 0134); LDS-M > PICN-M (WMW: P=. 0204); PICN-P > PICN-M (WMW: P=. 0486); and LDS-M > LDS-P (P=. 0022). However, comparison of the difference in gap length from before to after aging among the groups was not statistically significant (KW: P =. 3549). Conclusion: The cementation interfaces of CAD/CAM crowns on standardized titanium base abutments demonstrated a high percentage of gaps before and after thermomechanical loading. The composition of the restorative material and the nature of the interface influenced the interfacial gap dimension. Int J Prosthodont 2020;33:656–662. doi: 10.11607/ijp.6709 © 2020. by Quintessence Publishing Co Inc. All rights reserved

Effect of flapless ridge preservation with two different alloplastic materials in sockets with buccal dehiscence defects—volumetric and linear changes

Objective To test whether or not one out of two alloplastic materials used for ridge preservation (RP) is superior to the other in terms of volumetric and linear ridge changes over time. Materials and methods In 16 adult beagle dogs, the distal roots of P3 and P4 were extracted and 50% of the buccal bone plate removed. Ridge preservation was performed randomly using two different alloplastic bone grafting substitutes (poly lactic-co-glycolic acid (PLGA) coated biphasic calcium phosphate particles consisting of 60% hydroxyapatite (HA) and 40% beta-tricalcium phosphate (ß-TCP=test 1), (a biphasic calcium phosphate consisting 60% HA and 40% ß-TCP=test 2) and a resorbable collagen membrane or a control group (sham). Sacrifice was performed at three time-points (4, 8, 16 weeks later). Impressions were taken before extraction, after RP, and at sacrifice, allowing for assessment of volumetric changes. A multi-way ANOVAwas computed, and partial Type-II F tests were performed. Results Both ridge preservation procedures minimized the volume loss compared to spontaneous healing. The median buccal volume changes between pre-extraction and sacrifice were − 1.76 mm (Q1 = − 2.56; Q3 = − 1.42) for test 1, − 1.62 mm (Q1 = − 2.06; Q3 = − 1.38) for test 2, and − 2.42 mm (Q1 = − 2.63; Q3 = − 2.03) for control. The mean ridge width measurements did not show statistically significant differences between test 1 (− 2.51 mm; Q1 = − 3.25; Q3 = − 1.70) and test 2 (− 2.04 mm; Q1 = − 3.82; Q3 = − 1.81) (p = 0.813), but between test and control (− 3.85 mm; Q1 = − 5.02; Q3 = − 3.27) (p =0.003). Conclusions Both RP techniques were successful in maintaining the buccal contour from pre-extraction to sacrifice to a similar extent and more favorable compared to spontaneous healing. Clinical relevance Alloplastic materials can successfully be used for RP procedures. © Springer-Verlag GmbH Germany, part of Springer Nature 2017

Computer technology applications in surgical implant dentistry: a systematic review

Purpose: To assess the literature on accuracy and clinical performance of computer technology applications in surgical implant dentistry. Materials and Methods: Electronic and manual literature searches were conducted to collect information about (1) the accuracy and (2) clinical performance of computer-assisted implant systems. Meta-regression analysis was performed for summarizing the accuracy studies. Failure/complication rates were analyzed using random-effects Poisson regression models to obtain summary estimates of 12-month proportions. Results: Twenty-nine different image guidance systems were included. From 2,827 articles, 13 clinical and 19 accuracy studies were included in this systematic review. The meta-analysis of the accuracy (19 clinical and preclinical studies) revealed a total mean error of 0.74 mm (maximum of 4.5 mm) at the entry point in the bone and 0.85 mm at the apex (maximum of 7.1 mm). For the 5 included clinical studies (total of 506 implants) using computer-assisted implant dentistry, the mean failure rate was 3.36% (0% to 8.45%) after an observation period of at least 12 months. In 4.6% of the treated cases, intraoperative complications were reported; these included limited interocclusal distances to perform guided implant placement, limited primary implant stability, or need for additional grafting procedures. Conclusion: Differing levels and quantity of evidence were available for computer-assisted implant placement, revealing high implant survival rates after only 12 months of observation in different indications and a reasonable level of accuracy. However, future long-term clinical data are necessary to identify clinical indications and to justify additional radiation doses, effort, and costs associated with computer-assisted implant surgery

Success of 6-mm Implants with Single-Tooth Restorations

The aim of the study was to test whether implants of 6 mm in length perform equally well as 10-mm implants in terms of survival and marginal bone-level changes when supporting single crowns. Patients with a posterior single-tooth gap were randomly allocated to either the placement of a 6-mm (test) or 10-mm implant (control). The treatment protocol allowed for internal sinus lift but not for lateral bone augmentation. After a healing period of 10 wk, implants were loaded with screw-retained single crowns. Survival rates, number of pockets ≥5 mm, and bleeding-on-probing were assessed clinically. The change of marginal bone level and crown-to-implant ratios were analyzed by 2 examiners. Longitudinal intragroup analyses for marginal bone levels were performed applying the Wilcoxon signed rank test. Intergroup differences at baseline and at 3 y were compared using the Mann-Whitney U test. The effect of implant length and crown-to-implant ratio on changes of marginal bone level also was determined. Of 94 implants placed (47 test and 47 control), 78 implants (40 test and 38 control) were available for follow-up examination at 3 y of loading. One test implant was lost during the second year. Hence, implant survival was not significantly different between the 2 groups after 3 y (98% test; 100% control). We found no significant change in the crestal bone level from baseline to 3 y for test and control implants with -0.19 ± 0.62 mm and -0.33 ± 0.71 mm, respectively. The intergroup difference was not significant. Crown-to-implant ratios were not associated with a statistically significant difference in marginal bone loss. However, the number of sites with pockets ≥5 mm was significantly higher in the test group. Based on the 3-y assessment, the use of 6-mm implants can be considered a viable option when reconstructing posterior single tooth gaps (German Clinical Trials Registry: DRKS00006290)

Five-Year Survival of Short Single-Tooth Implants (6 mm): A Randomized Controlled Clinical Trial

The aim of the present study was to evaluate whether 6-mm dental implants in the posterior segments of either jaw perform equally well in terms of clinical and radiographic outcomes when compared with 10-mm implants after 5 y of loading. Patients with single-tooth gaps in the posterior area who were scheduled for implant therapy were randomly assigned to a group receiving either a 6- or 10-mm implant. After a healing period of 10 wk, implants were loaded with a screw-retained single crown and followed up at yearly intervals. Of 96 patients, 86 could be recalled after 5 y. The implant survival rates amounted to 91% (95% confidence interval: 0.836 to 0.998) for the 6-mm group and 100% for the 10-mm group ( P = 0.036). Median crown-to-implant (C/I) ratios were 1.75 (interquartile range [IQR], 1.50 to 1.90) for the 6-mm group and 1.04 (IQR, 0.95 to 1.15) for the 10-mm group, whereas the median marginal bone levels measured -0.29 mm (IQR, -0.92 to 0.23) for the 6-mm group and -0.15 mm (IQR: -0.93 - 0.41) for the 10-mm group after 5 y. The C/I ratio turned out to be statistically significant ( P < 0.001), whereas marginal bone levels showed no significant difference between the groups. The 6-mm implants exhibited significantly lower survival rates than the 10-mm implants over 5 y, whereas there was no difference between upper and lower jaws in terms of survival ( P = 0.58). Lost implants did not show any sign of marginal bone loss or peri-implant infection previous to loss of osseointegration. High C/I ratio and implant length had no significant effect on marginal bone level changes or technical and biological complications (German Clinical Trials Registry: DRKS00006290)

Fabrication, workflow and delivery of reconstruction: Summary and consensus statements of group 4. The 6th EAO Consensus Conference 2021

© 2021 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.Objectives: To report assessments of four systematic reviews (SRs) on (i) clinical outcomes of all-ceramic implant-supported crowns (iSCs), (ii) production time, effectiveness, and costs of computer-assisted manufacturing (CAM), (iii) computer-assisted implant planning and surgery (CAIPS) time and costs, and (iv) patient-reported outcome measures (PROMS). Material and Methods: An author group consisting of experienced clinicians and content experts discussed and evaluated the SRs and formulated consensus on the main findings, statements, clinical recommendations, and need for future research. Results: All four SRs were conducted and reported according to PRISMA and detailed comprehensive search strategies in at least three bibliometric databases and hand searching. The search strategies were deemed reproducible. Variation was noted regarding language restrictions and inclusion of grey literature, but the search comprehensiveness appeared persuasive. The SRs included bias risk assessments of the primary studies, and their study methodology impacted the interpretations of the extracted data. Conclusions: (i) There is limited evidence (49 NRCT) showing that veneered and monolithic all-ceramic iSCs have excellent outcomes observed up to 3 years. (ii) There is no evidence evaluating production time and effectiveness comparing subtractive and additive CAM of implant models, abutments and crowns. (iii) There is limited evidence (4 RCT) that CAIPS involves more time and costs when considering the entire workflow and for diagnostics, manufacturing, and insertion of the restoration. Time seems to be the decisive factor for higher costs. (iv) Patients’ comfort increases when optical compared to conventional impressions are used for fabricating iSCs and short-span FPDs (2 RCT, 5 NRCT)