Comparative soft and hard tissue responses to titanium and polymer healing abutments.

Limited information exists regarding soft tissue and hard tissue responses to abutments with different material composition. The aim of this study is to evaluate soft and hard tissue responses to titanium and polymer healing abutments over a 3-month period. Sixteen patients were included in this prospective trial. Implants were provisionalized with either titanium or polymer healing abutments. Changes of marginal bone level and soft tissue dimensions were recorded at implant installation and at 3 months.

Comparison of different methods of assessing alveolar ridge dimensions prior to dental implant placement.

BACKGROUND: The aim of this study was to compare ridge-mapping measurement before surgical flap reflection and measurement using images from cone beam computerized tomography (CBCT) to direct caliper measurement following surgical exposure of the bone. METHODS: Sixteen subjects with 25 sites for planned implant placement or ridge augmentation were recruited. An acrylic stent was fabricated for each subject. The stent provided three buccal/lingual pairs of consistent measurement points for each implant site located 4, 7, and 10 mm from the summit of the alveolar soft tissue. Two independent examiners participated. RESULTS: Comparisons of bucco-lingual ridge width using ridge-mapping versus direct caliper measurements showed that 94% and 89% of the pairs of measurement deviations were within +/- 1 mm for examiners 1 and 2, respectively. The corresponding comparison of CBCT images versus direct caliper measurements showed 70% and 55% agreement for examiners 1 and 2, respectively. CBCT image measurements provided lower levels of agreement than ridge-mapping measurements because of the more frequent and larger magnitudes of deviations compared to direct caliper measurements. CONCLUSIONS: Most often, ridge mapping provides measurements of the bucco-lingual ridge width consistent with those obtained by direct caliper measurement following surgical exposure of the bone. As applied in this study, CBCT was less consistent compared to direct caliper measurements and did not provide any additional, significant diagnostic information.

A training program to improve the ability of periodontal residents to estimate patients' pain experience.

BACKGROUND: The purpose of this study was to determine whether periodontal residents could enhance their ability to assess the pain levels experienced by their patients from probing, using visual analog scale (VAS) to record pain. We hypothesized that with increasing experience by repeated comparisons of the patients' VAS pain ratings with independent ratings by the residents, they would improve their ability to assess their patients' pain experiences. METHODS: For each of three periodontal residents, 40 consecutive patients with periodontal disease were asked to express the degree of pain they experienced during the probing. Independently, the residents rated the pain levels they perceived that the patients experienced. Subsequently, the residents compared the two VAS ratings and discussed differences in ratings with the patients. Descriptive statistics and intraclass correlation coefficients were used to analyze the findings. RESULTS: Differences between patients' and residents' VAS scores gradually became smaller over time for two of the residents. Results for the third resident were less compelling. CONCLUSIONS: This study indicated that the training program improved the residents' ability to estimate the pain experiences of their patients, at least for two of the three participating residents. This training program, using periodontal probing as a model, could serve as an educational tool for students and practitioners who want to improve their sensitivity to their patients' pain experiences.

Abutment Disconnection/Reconnection Affects Peri-implant Marginal Bone Levels: A Meta-Analysis.

PURPOSE: Preclinical and clinical studies have shown that marginal bone loss can be secondary to repeated disconnection and reconnection of abutments that affect the peri-implant mucosal seal. The aim of this systematic review and meta-analysis was to evaluate the impact of abutment disconnections/reconnections on peri-implant marginal bone level changes. MATERIALS AND METHODS: To address this question, two reviewers independently performed an electronic search of three major databases up to October 2015 complemented by manual searches. Eligible articles were selected on the basis of prespecified inclusion and exclusion criteria after a two-phase search strategy and assessed for risk of bias. A random-effects meta-analysis was performed for marginal bone loss. RESULTS: The authors initially identified 392 titles and abstracts. After evaluation, seven controlled clinical studies were included. Qualitative assessment of the articles revealed a trend toward protective marginal bone level preservation for implants with final abutment placement (FAP) at the time of implant placement compared with implants for which there were multiple abutment placements (MAP). The FAP group exhibited a marginal bone level change ranging from 0.08 to 0.34 mm, whereas the MAP group exhibited a marginal bone level change ranging from 0.09 to 0.55 mm. Meta-analysis of the seven studies reporting on 396 implants showed significantly greater bone loss in cases of multiple abutment disconnections/reconnections. The weighted mean difference in marginal bone loss was 0.19 mm (95% confidence interval, 0.06-0.32 mm), favoring bone preservation in the FAP group. CONCLUSION: Within the limitations of this meta-analysis, abutment disconnection and reconnection significantly affected peri-implant marginal bone levels. These findings pave the way for revisiting current restorative protocols at the restorative treatment planning stage to prevent incipient marginal bone loss.

Bacterial Colonization of the Implant-Abutment Interface (IAI) of Dental Implants with a Sloped Marginal Design: An in-vitro Study.

PURPOSE: The aim of this study is to utilize an in vitro dynamic loading model to assess the potential risk of bacterial invasion into the Implant Abutment Interface (IAI) microgap of dental implants with sloped marginal design. MATERIALS AND METHODS: Forty implants were divided into two groups (n = 20 per group) based on implant marginal design. Group 1 was comprised of implants with Morse-taper connection and conventional marginal design that connected to titanium abutments. Group 2 was comprised of implants with Morse-taper connection and sloped marginal design that connected to titanium abutments. The specimens were immersed in a bacterial solution of E. coli and loaded with 500,000 cycles of 160N using a chewing simulator. Following disconnection of fixtures and abutments, microbial samples were taken from the threaded portion of the abutment, plated and cultured under appropriate conditions. RESULTS: Ten out of twenty implants of Group 1 and eight out of twenty implants of Group 2 had IAI microgaps colonized by E. Coli. There was not a statistically significant difference in the mean number of E. Coli CFU detected between implants of Group 1 (mean 19.2, SD 23.6) and Group 2 (mean 12.5, SD18.9) (p > .05). CONCLUSIONS: The present study demonstrated that implants with a sloped marginal design exhibited similar risk for bacterial invasion into the IAI microgap under in vitro dynamic loading conditions compared to implants with conventional marginal design.

The Effect of Interimplant Distance on Peri-implant Bone and Soft Tissue Dimensional Changes: A Nonrandomized, Prospective, 2-Year Follow-up Study.

PURPOSE: To prospectively evaluate peri-implant bone and soft tissue dimension changes around adjacent implants placed at different horizontal interimplant distances. MATERIALS AND METHODS: Thirty partially edentulous patients, who underwent rehabilitation with two adjacent implant-supported crowns as part of their treatment plan, were assigned to three groups based on their prosthetic needs. Patients in group A (10 patients, 20 implants) were to have two implants placed at a 2-mm interimplant distance, patients in group B (10 patients, 20 implants) were to have two implants placed at a 3-mm interimplant distance, and patients in group C (10 patients, 20 implants) were to have two implants placed at an interimplant distance of > 4 mm according to their prosthetic needs. All patients received single-crown restorations after 3 months. Clinical examinations were performed at the time of crown placement (T3), and 6 months (T6), 12 months (T12), and 24 months (T24) after implant placement. Peri-implant bone levels were assessed radiographically at the time of implant placement (T0), and at T3, T12, and T24. RESULTS: One patient from group C did not return for follow-up examinations after implant placement. The mean (± standard deviation) horizontal interimplant distance was 1.97 ± 0.44 mm for implants in group A, 3.12 ± 0.15 mm for implants in group B, and 5.3 ± 0.64 mm for implants in group C. For group A, the mean marginal bone loss was 0.29 ± 0.51 mm at the T0-T3 interval, 0.31 ± 0.36 mm at the T0-T12 interval, and 0.27 ± 0.33 mm at the T0-T24 interval. For group B, the mean marginal bone loss was 0.16 ± 0.29 mm at the T0-T3 interval, 0.20 ± 0.28 mm at the T0-T12 interval, and 0.23 ± 0.28 mm at the T0-T24 interval. For group C, the mean marginal bone loss was 0.51 ± 0.84 mm at the T0-T3 interval, 0.45 ± 0.72 mm at the T0-T12 interval, and 0.44 ± 0.74 mm at the T0-T24 interval. For group A, the mean midproximal bone loss was 0.33 ± 0.50 mm at the T0-T3 interval, 0.45 ± 0.35 mm at the T0-T12 interval, and 0.40 ± 0.32 mm at the T0-T24 interval. For group B, the mean midproximal loss was 0.31 ± 0.37 mm at the T0-T3 interval, 0.32 ± 0.39 mm at the T0-T12 interval, and 0.33 ± 0.42 mm at the T0-T24 interval. For group C, the mean midproximal bone loss was 0.40 ± 0.44 mm at the T0-T3 interval and 0.41 ± 0.50 mm at both the T0-T12 and T0-T24 intervals. There were no statistically significant differences in marginal and midproximal bone crest loss between the different groups at any time point. CONCLUSION: The study failed to support the hypothesis that horizontal interimplant distance has an effect on peri-implant bone and soft tissue dimension changes for implants with internal conical implant-abutment interface connection and platform-switching characteristics.

Probing bone level measurements for determination of the depths of Class II furcation defects.

BACKGROUND: Probing bone measurements as an alternative to open bone measurements to evaluate regenerative procedures in furcation defects do not seem to be used as yet. The purpose of the present study was to investigate the reliability of probing bone measurements in such defects. METHODS: Fifteen patients scheduled for surgical treatment of a total of 30 mandibular molars with buccal or lingual Class II furcation defects were studied. During treatment, duplicate vertical and horizontal recordings of probing attachment levels, probing bone levels, and open bone levels were taken by independent examiners. RESULTS: Deviations of both vertical and horizontal recordings between the first and second examiners were within +/-1 mm in 90% to 100% of examined sites for all 3 measurements. Standard deviations of differences between pairs of duplicate recordings were also similar for the 3 measurements both for vertical and horizontal defect dimensions and amounted to 0.7 to 0.9 mm. On average, vertical and horizontal open bone levels were 0.9 to 1.1 mm deeper than probing bone levels. Probing bone levels, in turn, were 1.1 to 1.5 mm deeper than probing attachment levels. CONCLUSIONS: In view of the consistency demonstrated between probing bone level and open bone level measurements in mandibular Class II defects, coupled with the additional discomfort for the patient of a reentry surgery and a possible reentry traumatic effect, open bone level measurements do not seem necessary or even justified to evaluate effects of periodontal therapy in these defects, and can be substituted by probing bone measurements.

Cone beam computed tomographic evaluation of implants with platform-switched Morse taper connection with the implant-abutment interface at different levels in relation to the alveolar crest.

PURPOSE: The aim of this study was to evaluate marginal bone levels, with cone beam computed tomography, on the buccal and lingual aspects of implants placed with the implant-abutment interface (IAI) at different positions in relation to the alveolar crest. MATERIALS AND METHODS: Thirty patients in need of single-tooth rehabilitation were randomly assigned to three groups based on the position of the IAI in relation to the buccal aspect of the alveolar crest at the time of implant placement. Patients in groups 0, 1, and 2 had their implants placed level with the buccal crest or 1 or 2 mm apical to the buccal aspect of the alveolar crest, respectively. The implants were restored with screw-retained single crowns after 4 months. Marginal bone levels on the buccal and lingual aspects of the implants were evaluated at 12 months after implant placement. RESULTS: All groups of implants demonstrated significantly different crestal positions. Group 2 implants maintained the greatest subcrestal position (1.33 ± 0.86 mm) compared to the implants of group 0 (-0.04 ± 0.18 mm) and group 1 (0.34 ± 0.44 mm). There were no differences between groups in the level of the first bone-to-implant contact relative to the implant platform. Implants of group 0 exhibited less buccal bone remodeling (-0.08 ± 0.25 mm) compared to group 1 (-0.65 ± 0.45 mm) and group 2 (-0.85 ± 0.75 mm) implants. For groups 1 and 2 implants, there was a significant negative correlation between buccal wall thickness following the osteotomy and the amount of buccal bone remodeling. CONCLUSION: In this study, different responses were seen in the buccal and lingual peri-implant bone for implants with platform-switched Morse taper connections placed with the IAI at different locations in relation to the alveolar crest.

Placement of implants with platform-switched Morse taper connections with the implant-abutment interface at different levels in relation to the alveolar crest: a short-term (1-year) randomized prospective controlled clinical trial.

PURPOSE: This study sought to prospectively evaluate changes in marginal bone levels and soft tissue dimensions around platform-switched, Morse taper-connection implants placed with the implant-abutment interface (IAI) at different positions in relation to the alveolar crest. MATERIALS AND METHODS: Thirty patients in need of single-tooth rehabilitations were randomly assigned to three groups based on the position of the IAI in relation to the alveolar crest at the time of implant placement. Implants in groups 0, 1, and 2 (n = 10 in each group) were placed at the bone level or 1 mm and 2 mm below the buccal aspect of the alveolar crest, respectively. Four months later, the implants were restored with crowns. Clinical parameters were recorded at 4 and 12 months, and marginal bone levels were assessed radiographically at placement, 4 months, and 12 months. RESULTS: Mean marginal bone loss below the implant platform in group 0 implants was 0.18 ± 0.27 mm at 4 months and 0.27 ± 0.45 mm at 12 months. All implants in groups 1 and 2 exhibited no marginal bone loss below the implant platform, since the first bone-to-implant contact was located at or above the implant margin. At 12 months, implants in groups 1 and 2 exhibited greater mean bone loss above the implant platform compared to implants in group 0, but the differences were not statistically significant (group 0, 0.64 ± 0.49 mm; group 1, 0.81 ± 0.31 mm; group 2, 1.20 ± 0.68 mm). Implants in groups 1 and 2 exhibited a statistically significantly higher percentage of implant surfaces with bone on the implant platform compared to group 0 implants (90% versus 35%). CONCLUSIONS: In the present study, differences in peri-implant bone responses existed for implants placed with the IAI at different locations in relation to the alveolar crest.

Immediate loading of implants placed with the osteotome technique: one-year prospective case series.

BACKGROUND: There is limited information regarding marginal bone-level changes around immediately loaded implants placed with the osteotome technique. The aim of this case series is to prospectively evaluate the clinical and radiographic outcome of immediately loaded implants placed with the osteotome technique over a 12-month period. METHODS: Eighteen patients in need of oral prosthetic rehabilitation that included single implant placement in positions #4 to #13 and/or #20 to #29 participated in this prospective trial. A modified implant installation procedure with an under preparation of the implant bed using the osteotome technique and immediate loading of the implant was performed. Clinical examinations were performed at 2 weeks, 6 months, and 12 months of follow-up. Radiographic examinations were performed at implant installation and at the 6- and 12-month follow-up visits. RESULTS: One implant failed to integrate and was removed at 3 months after implant installation. Four of 20 implants had insertion torque value >35 Ncm. The mean marginal bone loss was -0.09 mm at the 6-month and -0.19 mm at the 12-month follow-up visits. CONCLUSION: The present case series indicates that implants placed with the osteotome technique and immediately loaded did not demonstrate a high insertion torque and exhibited minimal marginal bone loss.

Bacterial colonization of the implant-abutment interface using an in vitro dynamic loading model.

BACKGROUND: Previously, we demonstrated that the geometry of the fixture-abutment interface influences the risk of bacterial invasion into the internal part of the implant, although the contribution of loading on this invasion was not evaluated. The aim of the present study is to use an in vitro dynamic-loading model to assess the potential risk for invasion of oral microorganisms into the fixture-abutment interface microgap of dental implants with different fixture-abutment connection characteristics. METHODS: Twenty-eight implants were divided into two groups (n = 14 per group) based on their microgap dynamics. Group 1 was comprised of fixtures with internal Morse-taper connection that connected to standard abutments. Group 2 was comprised of implants with a four-groove conical internal connection that connected to multibase abutments. The specimens were immersed in a bacterial solution of Escherichia coli and loaded with 500,000 cycles of 15 N in a wear simulator. After disconnection of fixtures and abutments, microbial samples were taken from the threaded portion of the abutment, plated, and cultured under appropriate conditions. The difference between loosening and tightening torque value was also measured. RESULTS: One of the 14 samples in Group 1 and 12 of the 14 of samples in Group 2 developed multiple colony forming units for E. coli. Implants in Group 1 exhibited an increase in torque value in contrast to implants in Group 2, which exhibited a decrease. CONCLUSION: This study indicates that differences in implant design may affect the potential risk for invasion of oral microorganisms into the fixture-abutment interface microgap under dynamic-loading conditions.

Retrospective evaluation of crestal bone changes around implants with reduced abutment diameter placed non-submerged and at subcrestal positions: the effect of bone grafting at implant placement.

BACKGROUND: There is limited information regarding the effect of grafting of the osteotomy after subcrestal implant placement. The primary aim of this study is to retrospectively evaluate the effect of bone grafting of the defect between the bone crest and the coronal aspect of implants with reduced abutment diameter placed non-submerged and at subcrestal positions. METHODS: Records of 50 consecutive patients treated with subcrestally placed dental implants grafted with a xenograft (Group A) and 50 consecutive patients with subcrestally placed dental implants without any grafting material (Group B) were reviewed. For each implant, the radiographs after placement were compared to images from the last follow-up visit and evaluated regarding the following: 1) degree of subcrestal positioning of the implant, 2) changes of marginal hard-tissue height over time, and 3) whether marginal hard-tissue could be detected on the implant platform at the follow-up visit. RESULTS: The mean marginal loss of hard tissues was 0.11 ± 0.30 mm for Group A and 0.08 ± 0.22 mm for Group B. Sixty-nine percent of the implants in Group A and 77% of the implants in Group B demonstrated hard tissue on the implant platform. There were no statistically significant differences between the groups regarding marginal peri-implant hard-tissue loss. CONCLUSION: The present study fails to demonstrate that grafting of the remaining osseous wound defect between the bone crest and the coronal aspect of the implant has a positive effect on marginal peri-implant hard-tissue changes.

Crestal bone-level changes around implants placed in post-extraction sockets augmented with demineralized freeze-dried bone allograft: a retrospective radiographic study.

BACKGROUND: There is limited information regarding marginal crestal bone­level changes around implants placed in post-extraction sockets augmented with demineralized freeze-dried bone allograft (DFDBA). The aim of this study was to retrospectively compare bone-level changes around implants placed in post-extraction sockets augmented with DFDBA to implants placed in native bone. METHODS: Records of 30 consecutive patients treated with dental implants placed in post-extraction sockets augmented with DFDBA and 30 consecutive patients with implants placed in native bone were reviewed. For each implant, the radiographs from the surgical appointment were compared to those from the last follow-up visit and evaluated regarding changes of marginal bone level over time. RESULTS: The overall survival rate from baseline to the last follow-up visit was 100% for both groups. The mean marginal bone loss was 0.15 mm for both groups for a mean follow-up time of 12 months. There were no significant differences regarding the percentage of implants and implant surfaces demonstrating marginal bone loss. CONCLUSION: The present study indicates implants placed in post-extraction sockets augmented with DFDBA exhibited minimal marginal bone loss similar to implants placed in native bone.

Crestal bone changes around implants with reduced abutment diameter placed non-submerged and at subcrestal positions: a 1-year radiographic evaluation.

BACKGROUND: There is limited information about two-part implants placed in subcrestal positions. The aim of this study is to retrospectively evaluate the 1-year outcome of implants placed non-submerged and in a subcrestal position. METHODS: Records of 50 consecutive partially edentulous patients restored with dental implants were reviewed. For each implant, radiographs from the surgical appointment were compared to those from the 1-year follow-up visit and evaluated regarding: 1) the degree of subcrestal positioning of the implant, 2) changes of marginal hard tissue height over time, and 3) if the marginal hard tissue could be detected on the implant platform at the follow-up visit. RESULTS: The overall survival rate from baseline to the last recorded follow-up visit was 100%. At the surgery, the implants were placed, on average, 1.37 mm (mesial) and 1.28 mm (distal) subcrestally. The mean marginal loss of hard tissues was 0.11 +/- 0.30 mm. There were no statistical significant differences regarding the loss of marginal hard tissues between mesial and distal surfaces or the maxilla versus the mandible. There was no statistical significant correlation regarding the degree of subcrestal implant position and loss of marginal mineralized hard tissue (r = 0.15; P >0.05). The mineralized hard tissue on the implant shoulder was found in 69% of the implants at the 1-year follow-up visit. CONCLUSIONS: The present study reported a minimal loss of mineralized hard tissue around dental implants placed non-submerged and at subcrestal positions. In addition, these implants had hard tissue healing that extended onto the implant shoulders on most of the observed implants.

Bacterial colonization of the dental implant fixture-abutment interface: an in vitro study.

BACKGROUND: The geometry of the fixture-abutment interface (FAI) might influence the risk of bacterial invasion of the internal part of the implant. The aim of this study was to use an in vitro model to assess the potential risk for invasion of oral microorganisms into the FAI microgap of dental implants with different characteristics of the connection between the fixture and abutment. METHODS: Thirty implants were divided into three groups (n = 10 per group) based on their microgap dynamics. Groups 1 and 2 were comprised of fixtures with internal Morse-taper connections that connected to standard abutments and the same abutments with a 0.5-mm groove modification, respectively. Group 3 was comprised of implants with a tri-channel internal connection. Fixtures and abutments were assembled and allowed to incubate in a bacterial solution of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) and Porphyromonas gingivalis. Two standard abutments were either exposed to bacterial culture or left sterile to serve as positive and negative controls. After disconnection of fixtures and abutments, microbial samples were taken from the threaded portion of the abutment, plated, and allowed to culture under appropriate conditions. RESULTS: Three of the 10 samples in group 1 developed one colony forming unit (CFU) for A. actinomycetemcomitans, whereas zero of 10 samples developed CFUs for P. gingivalis. Ten of 10 and nine of 10 samples from groups 2 and 3, respectively, developed multiple CFUs for A. actinomycetemcomitans and P. gingivalis. CONCLUSION: This study indicated that differences in implant designs may affect the potential risk for invasion of oral microorganisms into the FAI microgap.

Recovery of putative pathogens from paper point sampling at different depths of periodontal lesions.

BACKGROUND: The aim of this study was to compare the recovery of three putative periodontal pathogens from periodontal lesions in samples using paper points inserted to different depths of the lesions. METHODS: Twenty 6-8 mm deep periodontal lesions with bleeding on probing were studied. Microbial samples were obtained using paper points inserted to three different depths of the lesions: orifice of lesion; 2 mm into the lesion; and to the base of lesion. Culturing was used for recovery and identification of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia. RESULTS: The recovery of each of the three putative periodontal pathogens was similar following sampling at the various depths of the lesions. CONCLUSIONS: The findings may be explained by the fact that the paper points become saturated as they pass through the orifice of the lesion. Absorption of microorganisms will therefore primarily occur at the orifice. It is also conceivable that the pathogens may be present in similar proportions throughout the various depths of the periodontal lesions.