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BackgroundPeri-implant diseases are emerging issues in contemporary implant dentistry. As biofilms play a critical role in peri-implant diseases, the characteristic of resisting bacterial adhesion would be ideal for dental implants. The aims of the study were to compare titanium (Ti) and zirconia (Zr) implants regarding the amount of biofilm formation at different time frames and assess the distribution of biofilm on different aspects of dental implants.MethodsBiofilm was developed on Ti and Zr dental implants with a peri-implant-related multispecies model with Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, and Porphyromonas gingivalis, for 3 and 14 days. Quantitative assessment was performed with the measurement of total bacterial viability (colony forming units, CFU/mg). Scanning electron microscopy (SEM) was used to evaluate biofilm formation on different aspects of the implants.ResultsThree-day-old biofilm on Ti implants was significantly higher than that on Zr implants (p < 0.001). The Ti and Zr groups were not significantly different for 14-day-old biofilm. SEM images demonstrated that 3-day-old biofilm on Zr implants was sparse while biofilm growth was more pronounced for 3-day-old biofilm on Ti implants and 14-day-old biofilm groups. It appeared that less biofilm formed on the valley compared to the thread top for 3-day-old biofilm on Zr implants. Differences between the valley and the thread top became indistinguishable with the development of mature biofilm.ConclusionWhile early formed biofilms show greater accumulation on Ti implants compared to Zr implants, older biofilms between the two groups are comparable. The distribution of biofilms was not uniform on different areas of implant threads during early biofilm development.

During implant maintenance, preserving a smooth surface on the machined transmucosal abutment is critical to reduce biofilm attachment and colonization. The present study compared the surface roughness and bacterial colonization of machined titanium surfaces after instrumentation with various materials. Forty-four machined grade 23 titanium discs were instrumented with a round polyether ether ketone (PEEK) tip, a plastic curette tip, or a pure titanium curette tip with piezoelectric devices. Before and after instrumentation, the surface roughness (Ra and Rz) values were analyzed with a profilometer and scanning electron microscopy (SEM). Streptococcus sanguinis was cultured and incubated for 24 hours on the instrumented discs, and colony-forming units per milliliter were obtained for each group. Samples instrumented with the metal ultrasonic tip significantly increased surface roughness compared with the other groups. This resulted in greater colonization by S. sanguinis than surfaces instrumented with PEEK tips or the negative control. Samples instrumented with PEEK and plastic tips did not exhibit any statistically significant increase in surface roughness, and SEM analysis revealed a significantly rougher surface of discs instrumented with metal compared with discs instrumented with plastic or PEEK tips despite the possibility of debris from tip dissolution. Our results suggest that instrumentation with metal ultrasonic tips with piezoelectric devices significantly increased machined titanium's surface roughness and elicited higher biofilm formation in vitro. Meanwhile, instrumentation of machined titanium with PEEK or plastic ultrasonic tips did not affect the surface roughness or bacterial adhesion. [ABSTRACT FROM AUTHOR]

The histologic findings and histomorphometric analysis of peri-implant tissues from nine functionally loaded implants from an adult cadaver were analyzed. Despite the presence of peri-implant bone loss, all implants were found to have a high degree of osseointegration, with the bone-implant contact (BIC) ranging from 69% to 88%. The mean BIC was 83.2% ± 4.3% (range: 76.5% to 87.7%) for maxillary implants and was 74.4% ± 7.1% (range: 69.4% to 84.9%) for mandibular implants, which were comparable. Relatively prominent bone remodeling and resorption with soft tissue ingrowth were observed in the vertical bony defects compared to the areas without intrabony components, which might represent the sequence of bone loss around the implants. [ABSTRACT FROM AUTHOR]

Growth factors are considered an important component for periodontal wound healing and a key element in the periodontal regeneration triad. Randomized controlled clinical trials have demonstrated that purified recombinant human platelet-derived growth factor-BB (rhPDGF-BB) in combination with bone graft materials is effective in treating intrabony periodontal defects. Many clinicians are currently using rhPDGF-BB in combination with xenogeneic or allogeneic bone. Therefore, the purpose of this case series was to assess the clinical effectiveness of combining rhPDGF-BB with xenogeneic bone substitutes to treat severe intrabony periodontal defects. Three patients with challenging deep and wide intrabony defects were treated using a combination of rhPDGF-BB and xenogeneic graft matrix. Probing depth (PD) reduction, bleeding on probing (BOP), mobility reduction, and radiographic bone fill (RBF) were observed for 12 to 18 months. PD decreased from 9 mm to 4 mm, BOP was eliminated, mobility decreased, and RBF ranged from 85% to 95% over the postsurgical observation period. These results indicate that combination of rhPDGF-BB with xenogeneic bone substitutes is a safe and effective graft that leads to favorable clinical and radiographic outcomes for treating severe intrabony periodontal defects. Larger case series or randomized studies will further elucidate the clinical predictability of this treatment protocol. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of regular implant drills to osseodensifying drills used in clockwise and counterclockwise motions on bone dimension change and primary implant stability. Materials and Methods: A total of 40 bone models were made (20 × 15 × 4 mm) from porcine tibia to represent implants placed in soft bone. Implant osteotomies were prepared in the bone models using one of the following techniques: (1) regular implant drills in a clockwise direction (group A), (2) regular implant drills in a counterclockwise direction (group B), (3) osseodensifying drills in a clockwise direction (group C), and (4) osseodensifying drills in a counterclockwise direction (group D). Bone-level tapered titanium alloy implants (4.1 × 10 mm) were placed following osteotomy creation. The implant stability quotient (ISQ) was measured after implant placement. Each bone model was scanned with an optical scanner to convert to Standard Tessellation Language (STL) files before and after the osteotomy creation. Presurgical and postsurgical STL files were superimposed, and the dimensional changes were measured at 1, 3, and 7 mm from the crestal bone. Histomorphometric analysis was done, and bone-to-implant contact percentage (BIC%) was calculated. Results: There were no significant differences in ISQ values (P = .239) between any of the groups. Histomorphometric analysis showed implants in group D had significantly higher BIC% than groups A (P = .020) and B (P = .009). The amount of bone expansion decreased with distance from the crest (P < .001). Groups B (P = .039) and D (P = .001) showed significant expansions at all levels compared with group A. No other statistically significant differences in dimensional change were found between groups. Conclusion: Both regular and osseodensification burs used in a counterclockwise motion contribute to expansion of bone dimension compared to conventional drilling methods. [ABSTRACT FROM AUTHOR]

Although a smaller size field of view (FOV) of cone-beam computerized tomography (CBCT) reduces radiation exposure, its effect on the accuracy of static computer-aided implant surgery (s-CAIS) remains unknown. This study aimed to evaluate the impact of the size of FOV on the accuracy of s-CAIS and to investigate if the arch affects this effect. A total of 32 implant sites on 8 identical scannable models (maxillae and mandibles) were randomly allocated to 2 FOV sizes: test (5 × 5 cm) and control (10 × 10 cm). All models were scanned with an intraoral scanner (IOS). With the registration of the surface scan and CBCT image, a prosthetic-driven implant position was planned. Following the fabrication of surgical templates, a single-blinded surgeon placed all implants with the fully guided s-CAIS protocol. IOS captured the implant positions with the scan body attached. Implant-planning software measured the angular deviation, 3-dimensional (3D) deviation at the crest, and 3D deviation at the apex between preplanned and actual implant positions. Two-way analysis of variance was used to analyze the effect of FOV and arch on the deviations. The size of FOV did not show a significant effect (P >.198) on angular deviation, 3D deviation at the crest, or 3D deviation at the apex. No significant difference was found when comparing the effect of the size of FOV between the maxillary and mandibular implants. In conclusion, the use of small FOV CBCT demonstrated comparable accuracy of s-CAIS to the use of medium FOV CBCT. [ABSTRACT FROM AUTHOR]

To compare the amount of bone expansion, bone density change, and implant primary stability with an osseodensification technique to a conventional drilling protocol. Materials and Methods: Twenty-four bovine rib segments (20 × 25 × 4 mm) with a 1-mm outer layer of cortical bone were randomly divided into two groups: an osseodensification group and a conventional drilling group. Each bone sample received one 4.1 × 10–mm implant. The density of the peri-implant bone before and after osteotomy was measured. After implant placement, primary stability was assessed. A laser surface scanner was used before and after implant placement to compare the dimension of crestal bone width and volumetric expansion. Histomorphometric analysis was performed to compare the bone-to-implant contact percentage (BIC%) of the two groups. Results: The peripheral and apical bone mineral density around the implants was significantly increased, and a statistically significantly higher peripheral BIC% was found in the osseodensification group. A significant increase in volume and bone width after implant placement was found in both groups. However, there were no significant differences in volume and bone width change at all three locations and in implant stability between the osseodensification and conventional drilling protocols. Conclusion: Within the limitations of this study, the osseodensification protocol increased the bone mineral density and primary bone-to-implant contact. Also, this study suggests that implant placement by osseodensification or conventional drilling can increase ridge dimensions in narrow alveolar ridges. [ABSTRACT FROM AUTHOR]