Effect of soft tissue thickness on crestal bone loss of early loaded implants with platform switching: 1- and 5-year data.

Objectives: The aim of this retrospective study was to evaluate the effect of vertical soft tissue thickness (STT) on crestal bone loss (CBL) of early loaded implants after 1 and 5 years. Method and materials: Forty-four tapered implants with platform switching and conical connection were placed in the posterior mandible and maxilla to rehabilitate edentulous sites. STT at implant sites was divided into two groups: thin (n = 21, mean STT = 2.0 ±â€¯0.3 mm) and thick (n = 23, mean STT = 3.0 ±â€¯0.8 mm). The implants were loaded after 6 to 8 weeks. Survival and success rates and CBL were measured after 1 and 5 years. Results: The survival and success rates at 1 and 5 years were 100% and 97.8%, respectively. At the 1-year follow-up, the CBL of the thin and thick gingival groups was 0.96 ±â€¯0.49 and 0.55 ±â€¯0.41 mm, respectively; the difference was statistically significant (P = .004). At 5 years, the CBL of the thin and thick gingiva groups increased to 1.12 ±â€¯0.84 and 0.65 ±â€¯0.69 mm, respectively; the difference was not statistically significant (P = .052). Conclusion: At 1 year, the CBL was more pronounced at sites with a thin gingiva; at 5 years the difference between the groups was not statisically significantly different. Within the limitations of this study, early loading of implants with platform switched and conical connection was safe.

Clinical, Histological, and Histomorphometric Evaluation of Demineralized Freeze-Dried Cortical Block Allografts for Alveolar Ridge Augmentation.

Autogenous bone-block grafts are the "gold standard" for block bone grafting, but have several disadvantages. Allografts have the potential to overcome these disadvantages. The purpose of this study was to evaluate the clinical and histomorphometric features of demineralized freeze-dried cortical block allografts (DCBA) used for ridge augmentation. Eleven patients who showed bone deficiencies of <5 mm in the horizontal plane were included in this study. The recipient sites were reconstructed with DCBA. The primary outcomes of interest were bone-width measurements, postoperative clinical evaluations, and histomorphometric analysis of the biopsy samples collected during the implant surgery. Clinical analysis showed that the mean gain in horizontal bone was 1.65 ±â€Š0.14 mm, and that the mean percentage of graft resorption was 5.39 ±â€Š2.18%. On postoperative day 7, edema, pain, and bruising were observed in 18.2%, 0%, and 9.1% of the patients, respectively. In the biopsy samples, the mean percentages of newly formed bone, residual block allograft, and marrow and connective tissue were 40.30 ±â€Š24.59%, 40.39 ±â€Š21.36%, and 19.30 ±â€Š15.07%, respectively. All of the block grafts were successfully integrated into the recipient sites. DCBA may be a viable alternative for treating both deficient maxillary and mandibular alveolar ridges.

Implant positioning errors in freehand and computer-aided placement methods: a single-blind clinical comparative study.

PURPOSE: Simultaneous insertion of multiple implants may exhibit suboptimal positions, especially in edentulous jaws considered for a fixed restoration. The aim of this study was to compare the incidence of and confounding factors in implant positioning errors related to the use of freehand and computer-aided treatment methods. MATERIALS AND METHODS: A total of 353 implants were placed in 54 patients with at least one edentulous jaw using freehand and computer-aided methods involving 16 mucosa- and 12 bone-supported single- and multiple-type stereolithographic surgical guides. At the stage of prosthesis delivery, a blinded examiner evaluated seven positioning error criteria. Results were analyzed by chi-square test and logistic regression. RESULTS: Interproximal emergence (OR = 2.82, P < .0001), insufficient interimplant distance (OR = 1.42, P < .0001), and improper parallelism (OR = 1.24, P = .001) errors were significantly higher in implants placed by the freehand method. The highest probability of positioning error (88%) was associated with the use of the freehand method, whereas the lowest (6%) was associated with single-type, mucosa-supported guides with other significant confounding factors. CONCLUSION: Utilizing computer-aided methods may alleviate the occurrence of implant positioning errors that are frequently associated with the freehand method. The use of software planning with enhanced viewing capabilities and single-type, mucosa-supported stereolithographic surgical guides in suitable patients minimizes errors.

Osseointegration and stability of a modified sand-blasted acid-etched implant: an experimental pilot study in sheep.

OBJECTIVE: The aim of this pilot study was to compare the early-term osseointegration characteristics of standard (SLA) and modified sand-blasted and acid-etched (modSLA) implants in an experimental animal model. MATERIAL AND METHODS: A total of 30 SLA and modSLA implants were placed to the tibiae of three sheep and the insertion torque value (ITV) and resonance frequency analysis (RFA) measurements were performed. RFA measurement was repeated on 3 and 6 weeks healed implants after which the animals were sacrificed for histomorphometric analysis. Bone-to-implant contact was assessed on the non-decalcified sections. Six weeks healed implants were also subjected to the reverse torque test (RTT). Results were analyzed by the Friedman test, Kruskal-Wallis test and Spearman rank correlation test. RESULTS: All implants reached to a strong primary stability with a mean 36.13 ± 2.47 and 35.47 ± 2.85 N/cm ITV. In the surgical stage, RFA values for SLA and modSLA implants were found to be 72.27 ± 3.17 and 71.6 ± 2.87, respectively. After 3 weeks of healing, mean BIC% (80.64 ± 13.89%) and RFA value (76.8 ± 1.14) of modSLA implants were significantly higher (P=0.0002) than that of SLA implants (64.39 ± 21.2 BIC% and 74.2 ± 4.76 RFA). However, no statistically significant difference between SLA and modSLA implants was recorded after 6 weeks of healing. Both implants revealed similar results in the RTT test (115.2 ± 4.14 and 117 ± 4.47 N/cm for SLA and modSLA implants, respectively). No correlation was found between RFA and BIC%. CONCLUSION: Within the limits of this pilot study, it can be concluded that modSLA implants achieve a higher bone contact and stability at earlier time points when compared with SLA implants.

Implant surgery using bone- and mucosa-supported stereolithographic guides in totally edentulous jaws: surgical and post-operative outcomes of computer-aided vs. standard techniques.

OBJECTIVES: The aim of this study was to compare the surgical and post-operative outcomes of a computer-aided implant surgery performed by bone- and mucosa-supported stereolithographic (SLA) guides against the standard technique. MATERIAL AND METHODS: Multiple- and single-type SLA guides from two commercial manufacturers were produced and a total of 341 implants were placed to 52 patients using the standard technique (Control group), bone- (bone-supported guide [BSG] group) and mucosa-supported SLA guides (Flapless group) in 21, 16 and 15 patients, respectively. Surgical duration (min), number of analgesics (tablets) as well as hemorrhage, difficulty in mouth opening (or trismus) and other incidences were recorded. Pain and swelling was assessed using the visual analog scale (VAS). Parametric and non-parametric tests were used for statistical analysis (P<.05). RESULTS: The mean surgery duration (23.53+/-5.48 min) and the number of analgesics consumed (four tablets) in the Flapless group were lower than those in the control (68.71+/-11.4 min and 10 tablets) and BSG groups (60.94+/-13.07 min and 11 tablets, P<0.01). The change in pain scores (VAS) and the number of analgesics consumed in time were statistically significant (P<0.01 and 0.05, respectively) and the Flapless group reported a lower pain score than the BSG (P<0.01) and Control groups (P<0.001). The Flapless group experienced less hemorrhage (chi(2)=4.12, P=0.041 on the day of surgery) and fewer instances of trismus (chi(2)=6.91, P=0.031 the day after surgery). The differences in early-term failures were not statistically significant between the groups (log-rank test: P=0.782). CONCLUSION: The use of mucosa-supported single SLA guides for flapless implant placement may help reduce the surgery duration, pain intensity, related analgesic consumption and most other complications typical in the post-implant surgery period. However, there are particular drawbacks in both guide types and further studies are required to confirm the prosthodontic conformity and long-term success of implants placed using computer-assisted techniques.

A clinical comparison of prosthetic complications of implant-supported overdentures with different attachment systems.

OBJECTIVES: The objective of this clinical study was to evaluate the prosthetic complications of patients with 2 to 4 implants splinted with a round bar or with 2 to 4 unsplinted implants with ball attachments during the follow-up period. METHODS: A total of 26 patients were included in this study. Patients were randomly provided with a round bar or with ball attachments that were used to retain overdentures. During follow-up visits, the following prosthetic complications were recorded: round bar fracture, fractured overdenture, hygiene complications, abutment screw loose, worn O-ring or replacement of O-ring attachment, and fractured retention clip. The functioning period of overdentures in the round bar group ranged from 12 to 72 months (mean 49), and from 12 to 40 months (mean 23) in the ball attachment group. RESULTS: A total of 20 prosthetic complications were recorded in both groups. No differences in prosthetic complications were observed for 2 attachment systems. CONCLUSION: Implant-supported overdentures with bar or ball attachments may be considered to be reliable methods in the treatment of the edentulous individuals.

Effects of sinus membrane perforations on the success of dental implants placed in the augmented sinus.

BACKGROUND: Maxillary sinus lifting procedure enables clinicians to place implant-supported prostheses even in cases with very limited vertical bone height of the maxillary sinus. The aim of this study was to evaluate the implant success with regard to effects of the sinus membrane perforations that occurred during sinus lifting surgery. METHODS: The study group consisted of 91 patients (29 females and 54 males) with edentulous posterior maxilla. Implant placement combined with sinus lifting surgery was performed, and 259 implants were inserted. Sinus membrane perforations were detected in 12 sinus sites. After proper treatment of perforations, 26 implants were placed into perforated sinus areas. Baseline panaromic radiographs were taken before the beginning of prosthetic treatment. Panaromic radiographs taken at the last recall were used for evaluation and compared to the baseline panaromic radiographs using image analysis software to reveal the peri-implant resorption rate for the implants placed in perforated and non-perforated sinus area. The modified sulcus bleeding index and plaque index were used for the assessment of soft tissue conditions. RESULTS: Eleven implants were lost during the follow-up period, resulting in an overall survival rate of 95.9%. Two failures occurred in the group with sinus perforations. There was no statistically significant difference regarding peri-implant bone resorption (P = 0.778) and soft tissue conditions for implants placed into perforated-augmented sinus areas and augmented sinus areas. CONCLUSION: Within the limits of this study, perforation of the sinus membrane did not compromise the osseointegration process or the success of dental implants placed in the augmented maxillary sinus.

Evaluation of sleep bruxism by polysomnographic analysis in patients with dental implants.

PURPOSE: The aims of the present study were to use polysomnographic analysis to confirm sleep bruxism (SB) and to evaluate clinical findings of dental implant treatment in SB patients. MATERIALS AND METHODS: The present study comprised the retrospective analysis of 368 patients with a total of 838 endosseous implants. Nineteen patients who experienced mechanical complications, such as implant or abutment fractures, loosened gold screws, or occlusal surface wear or damage, were selected for polysomnographic analysis to monitor sleep symptoms. Six patients in the study group were identified as having SB, and this was confirmed by polysomnographic analysis. RESULTS: The SB electromyographic episodes were at least 20% of the patients' maximum voluntary contractions while awake and were scored. Most of the bruxism episodes (80%) were seen in light sleep stages. Only 5% of bruxism episodes were detected during rapid-eye-movement sleep. Sleep stage recordings were similar in all individuals. Bruxism episodes did not cause arousals. Patients were unaware of their nocturnal parafunctional habits. Despite protection with night guards, all patients were reported to have continued bruxism. DISCUSSION: Since possible occlusal parafunctional habits may be evident in any stage of dental treatment, treatment outcome risks must be considered. CONCLUSIONS: Polysomnographic study was evaluated as an effective, low-cost method to confirm occlusal parafunctional habits during sleep. Precautions against SB in patients having dental implant treatment have not been properly clarified. However, night guard protection appears to have some validity in patients having sleep bruxism.

Comparison of 2 retentive systems for implant-supported overdentures: soft tissue management and evaluation of patient satisfaction.

BACKGROUND: The aim of the present study was to compare the peri-implant soft tissue health status of implants supporting overdentures with bar attachments or ball attachments in the mandible, as well as patient satisfaction with these attachment types. METHODS: The study included a Dolder bar group with 18 cases (43 implants) and a ball attachment group with 18 cases (51 implants). The mean function period in the Dolder bar group was 49 months (range: 12 to 72 months) and in the ball attachment group, the mean was 23 months (range: 12 to 40 months). Implants were clinically evaluated by using a modified plaque index (mPI), modified sulcus bleeding index (mSBI), and probing depths. Patient satisfaction with the treatment was recorded using a questionnaire. RESULTS: mPI, probing depth, and mSBI did not statistically differ between groups (Mann-Whitney U test, P > 0.05). Patient satisfaction was similar with both retentive systems. CONCLUSION: Within the limits of this study, we concluded that there was no significant difference between the 2 attachment types used for implant-supported overdentures with respect to the soft tissue health status or patient satisfaction.