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AIM To test whether an equine bone substitute block used for guided bone regeneration (GBR) of peri-implant defects renders different results from bovine block or particulated bone substitutes regarding the dimensions of the augmented ridge and the amount of new bone. MATERIAL AND METHODS Mandibular premolars and molars were extracted in eight dogs. After 4 months, four semisaddle bone defects were created in each mandible and one titanium implant was inserted into every site. Bone augmentation by GBR was attempted using the following randomly assigned modalities: (i) particulated deproteinized bovine bone mineral (DBBM) + a collagen membrane (CM), (ii) block DBBM + CM, (iii) equine bone substitute block + CM, and (iv) empty controls. After 4 months, one central and two lateral sections of each site were prepared. Descriptive histological and histomorphometrical assessments were performed evaluating the augmented area (AA) within the former bone defect, the area of mineralized tissue (MT), non-mineralized tissue (NMT), and residual bone substitute (BS) within AA, the horizontal thicknesses of the augmented region (HTaugm ) and of the mucosa (HTmucosa ). RESULTS At the central sections, AA measured 11.2 ± 3.3 mm(2) for the equine block, 9.5 ± 2.6 mm(2) for DBBM block, 7.9 ± 4.8 mm(2) for particulated DBBM, and 2.4 ± 2.1 mm(2) for the empty control. All GBR groups rendered significantly higher values of AA in comparison with control (P 0.05). The differences in AA between GBR groups did not reach statistical significance (P > 0.05). The equine block rendered the highest values in HTaugm , although only the differences between equine block and control as well as equine block and DBBM block were statistically significant (P 0.05). With respect to HTmucosa , all GBR groups reached significantly higher values compared to control (P 0.05). The equine block revealed the most pronounced signs of graft degradation. CONCLUSIONS Guided bone regeneration lead to higher ridge dimensions and thicker covering mucosa than empty controls. The equine block with CM resulted in the most favorable outcomes regarding the maintenance of ridge contour. There were no significant differences regarding amount of new bone between GBR treatments. Material & Methods: Mandibular premolars and molars were extracted in 8 dogs.After 4 months, four semi-saddle bone defects were created in each mandible and one titanium implant was inserted into every site. Bone augmentation by GBR was attempted using the following randomly assigned modalities: (1) (primary outcome parameter) and of the mucosa (HT mucosa ).Results: At the central sections AA measured 11.2 ± 3.3 mm 2 for the equine block, 9.5 ± 2.6 mm 2 for DBBM block, 7.9 ± 4.8 mm 2 for particulated DBBM, and 2.4 ± 2.1 mm 2 for the empty control. All GBR groups rendered significantly higher values of AA in comparison to control (p ≤ 0.05). The differences in AA between GBR groups did not reach statistical significance (p > 0.05). The equine block rendered the highest values in HT augm , ...

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OBJECTIVE To evaluate the volumetric changes occurring from prosthesis insertion to the 1-year follow-up (FU) using one-and two-piece dental implants. METHODS Sixty patients were randomly assigned to receive one-piece or two-piece implants. Casts were obtained at baseline (insertion of final reconstruction) and at 1 year of loading. Finally, 33 pairs of casts (BRA = 18, STM = 15) were deemed appropriate for volumetric analysis of the peri-implant tissues. If the patients had more than one implant, one was randomly selected for analysis. Casts were scanned to obtain stereolithography (STL) files. Baseline and 1-year FU digital models were superimposed with an image analysis program. Linear and volumetric measurements were performed including (i) crown height changes (CHCs), (ii) volumetric changes, and (iii) changes in tissue thickness at three levels below the mucosal margin on the buccal side of the implants (at 1,3, and 5 mm). The Mann-Whitney U-test and the paired t-test were used to analyze the data between the two groups using the patient as the unit of analysis. RESULTS No significant baseline differences were observed between the one-and two-piece groups for the linear measurements. The mean CHCs in the two-piece group amounted to 0.02 mm (SD ± 0.32), whereas the one-piece group exhibited a change of -0.17 mm (±0.57). The mean volume changes (VCs) were -0.12 mm (±0.27) (two-piece group) and -0.03 mm (±0.29) (one-piece group). With regard to the changes in tissue thickness, the two-piece group presented a change of -0.15 mm (±0.20) at 1 mm, -0.06 mm (±0.20) at 3 mm, and -0.2 mm (±0.51) at 5 mm. The respective values for the one-piece group were -0.03 mm (±0.35), 0.01 mm (±0.28), and -0.01 mm (±0.51) at the three levels. None of the differences in linear measurements between baseline and the 1-year FU reached significance. Positive correlations were seen for tissue thickness changes at 1 and 3 mm for both groups (P < 0.05). Significant positive correlations were found for VCs and tissue thickness at 1 mm for the two-piece group and for VCs and tissue thickness at 1,3, and 5 mm for the one-piece group (P < 0.05). CONCLUSION Within the first year of loading, minimal changes occur with regard to tissue thickness, crown height, and facial volume for both implant types. ABSTRACTObjective: to evaluate the volumetric changes occurring from prosthesis insertion to the one year follow-up using one-and two-piece dental implants. Methods:60 patients were randomly assigned to receive one-piece or two-piece implants.Casts were obtained at baseline (insertion of final reconstruction) and at one year of loading. Finally, 33 pairs of casts (BRA=18, STM=15) were deemed appropriate for volumetric analysis of the peri-implant tissues. If the patients had more than one implant, one was randomly selected for analysis. Casts were scanned to obtain stereolithography (STL) files. Baseline and one-year follow-up digital models were superimposed with an image analysis program. Linear and volumetric measurements were perfo...

OBJECTIVE To assess whether or not peri-implant soft tissue dimensions and hard tissue integration of loaded zirconia implants are similar to those of a titanium implant. MATERIALS AND METHODS In six dogs, two one-piece zirconia implants (VC, ZD), a two-piece zirconia implant (BPI) and a control one-piece titanium implant (STM) were randomly placed. CAD/CAM crowns were cemented at 6 months. Six months later, animals were killed and histomorphometric analyses were performed, including: the level of the mucosal margin, the extent of the peri-implant mucosa, the marginal bone loss and the bone-to-implant contact (BIC). Means of outcomes variables were calculated together with their corresponding 95% confidence intervals. RESULTS In general, the mucosal margin was located coronally to the implant shoulder. The buccal peri-implant mucosa ranged between 2.64 ± 0.70 mm (VC) and 3.03 ± 1.71 mm (ZD) (for all median comparisons p > 0.05). The relative marginal bone loss ranged between 0.65 ± 0.61 mm (BPI) and 1.73 ± 1.68 mm (ZD) (buccal side), and between 0.55 ± 0.37 mm (VC) and 1.69 ± 1.56 mm (ZD) (lingual side) (p > 0.05). The mean BIC ranged between 78.6% ± 17.3% (ZD) and 87.9% ± 13.6% (STM) without statistically significant differences between the groups (p > 0.05). CONCLUSIONS One-and two-piece zirconia rendered similar peri-implant soft tissue dimensions and osseointegration compared to titanium implants that were placed at 6 months of loading. Zirconia implants, however, exhibited a relatively high fracture rate. Scientific rationale for the study: Patient demands include alternatives to classic titanium dental implants. For that purpose, zirconia implants were developed and brought on the market. Even though the number of dental implants made of zirconia is increasing, preclinical and clinical data are scarce comparing titanium and zirconia one-and two-piece dental implants on a soft and hard tissue level or with or without a loading period.Principal findings: After a loading period of 6 months one-and two-piece zirconia and one-piece titanium dental implants render similar peri-implant soft tissue dimensions in terms of the extent of the junctional epithelium and the peri-implant mucosa. The relative marginal bone loss depends on the individual implant design. Fractures of zirconia implants were frequent, however. Practical implications:Within the limitations of this study zirconia and titanium dental implants render similar hard and soft tissue integration. Zirconia implants should be compared to titanium dental implants in long-term randomized controlled clinical trials. 3 AbstractObjective: To assess whether or not peri-implant soft tissue dimensions and hard tissue integration of loaded zirconia implants are similar to those of a titanium implant. Materials and methods:In 6 dogs, two one-piece zirconia implants (VC, ZD), a two-piece zirconia implant (BPI) and a control one-piece titanium implant (STM) were randomly placed.CAD/CAM crowns were cemented at 6 months. Six months later, animals were sacri...