International Journal of Oral & Maxillofacial Implants最新文献

Purpose: To examine the changes of dentoalveolar structures and pathologies in the maxillary sinus before and after dental implant surgery alone or with direct vs indirect sinus lifting using CBCT images of the maxillary posterior region.

Materials and methods: Preoperative and postoperative CBCT images of 50 sinus sites and the alveolar bone around 83 implants in 28 patients were evaluated. Maxillary sinus pathologies were classified as mucosal thickening (MT), mucus retention cyst (MRC), polyp, and sinusitis before and after surgery. The changes after surgery were determined to be no change, reduction in pathology, or increase in pathology. Comparisons of pathology changes among the treatment groups were evaluated statistically with chi-square test, McNemar test, and Mann-Whitney U test.

Results: Of the 50 sinuses evaluated for the presence of sinus pathology, 24 of 50 did not change postoperatively, the pathology increased in 10 sinuses, and the pathology decreased in 16. When the maxillary sinus regions were evaluated after indirect sinus lifting, direct sinus lifting, and in patients who had only implant surgery, there was no statistically significant difference between pathology distribution in terms of the procedure applied to the sinus (P > .05). However, in the maxillary sinuses with a pathology before implant placement were evaluated postoperatively, a statistically significant difference was found in favor of the presence of a change in pathology (ie, improvement or a decrease; P < .05). The maxillary sinuses without pathology before implant placement showed a statistically significant difference for no change; ie, continuation of the healthy state (P < .05).

Conclusion: This study showed that surgical procedures could have a direct effect on the sinus membrane and maxillary sinus. Both the implant procedure and surgical approach may have an effect on maxillary sinus pathology, as well as an increase or decrease of the pathology. Hence, further studies with a longer-term follow-up should be performed to better understand the correlation between implant surgery and pathology.

Purpose: The objective of this in vitro study was to evaluate the activity of local gel containing metronidazole (MN) in the leakage area, which was analyzed by the DNA-DNA checkerboard hybridization method. Materials and Methods: Thirty-six sets of Morse taper/mini-pillar implants were used in this study. These implants were equally divided into the following three groups: MN gel (test group), no MN gel (negative test group), and no gel (control). The gel was prepared with metronidazole (15%). Unstimulated saliva samples were collected, transferred to a Falcon tube, and stored at 37°C. The sets were partially immersed in microtubes containing 300 μL of saliva and were incubated at 37°C ± 1°C for 7 days. Microbial infiltration was evaluated (37 bacterial species and 5 species of Candida). The results were analyzed with Wald-Type, ANOVA, and multiple comparisons analysis between groups. Results: After comparing the quantity of microorganisms, both gel-treated groups (no MN gel and MN gel) had more significant microorganism presence than the control group (P < .001), and no significant result was found between the no MN gel and MN gel groups (P > .05). Regarding the bacteria found, the most common were Aggregatibacter actinomycetemcomitans, Prevotella melaninogenica, Bacteroides fragilis, and Candida tropicalis. Conclusion: Within the limitations of this study, it was concluded that the gel containing metronidazole used in this study was not effective in preventing the infiltration of microorganisms through the Morse taper implant-abutment interface.

Purpose: To compare different socket sealing approaches for alveolar ridge preservation and assess the dimensional changes and histologic characteristics of soft and hard tissues in a 4- to 6-month period. Material and Methods: A total of 22 patients with indicated single-tooth extraction in the maxillary nonmolar region were eligible for this study. After CBCT scanning and minimally traumatic tooth extraction, the alveolar sockets were filled with demineralized bovine bone mineral with collagen (DBBM-C) in patients from all groups except for those in the control group. Patients were divided into groups for socket sealing as follows: unsealed/spontaneous healing (control; n = 6), collagen matrix (n = 5), collagen membrane (n = 5), and autogenous graft (n = 6). A second CBCT scan was taken 4 to 6 months after extraction, and a trephine biopsy of soft and hard tissues was collected during implant placement. Tomographic dimensional changes were compared between groups. Intragroup tomographic evaluation and histological analysis were also performed. Results: Analysis of dimensional changes did not detect differences between the socket sealing groups (P > .05). In an intragroup evaluation, the height of the buccal bone and cross-sectional area of the alveolar ridge were significantly lower 4 to 6 months after extraction for the control group (P = .031). Histological analysis revealed that the socket sealing approach had no impact on hard and soft tissue formation. Conclusion: The data from the present study suggest that socket sealing with a collagen matrix, a collagen membrane exposed to the oral cavity, or an autogenous punch graft had no difference in the effects on volumetric maintenance and tissue formation in a period of 4 to 6 months.

Purpose: To retrospectively evaluate the clinical outcomes of immediately loaded zygomatic implants combined with anterior regular implants (hybrid zygoma) for the fixed rehabilitation of atrophic maxillae. Materials and Methods: A total of 18 patients were enrolled in this study and treated with the hybrid zygoma concept by an experienced surgeon. Follow-up visits were planned after 1 week, 3 weeks, 4 months, 6 months, then annually. At the last follow-up appointment (mean: 36 months after surgery; range: 24 to 52 months), the prostheses were unscrewed and the implants and peri-implant tissues were examined. The primary outcome evaluated was implant success. Following the criteria proposed by Aparicio et al, implant success was classified in five grades, with grade I representing the best condition and grade V representing a failure. At the annual check-up, patients were asked to fill out a questionnaire to evaluate their satisfaction with their oral rehabilitation. Results: A total of 80 implants (34 zygomatic and 46 regular) were inserted. One zygomatic implant was lost in one patient, and two regular implants failed in two other patients. Of the zygomatic implants, 24 (70.6%) presented a success grade I, 9 (26.5%) a success grade II, and 1 (2.9%) a grade V. Sinusitis was the most common biologic complication, occurring in two patients (5.6%). Two patients showed unilateral upper lip paresthesia that was persistent at the last follow-up appointment. According to the annual follow-up visit questionnaire data, 72%, 89%, and 94% of patients declared that they were satisfied with their phonetic ability, chewing ability, and esthetics, respectively. Conclusion: Although zygomatic implants combined with anterior regular implants present a higher risk of complications than traditional implantology, they allow for immediately loaded full-arch fixed rehabilitation of patients with advanced atrophy of the posterior maxilla, which provides satisfactory chewing ability, esthetics, and phonetics.

Purpose: To evaluate the long-term functional and esthetic effects of immediate implantation combined with guided bone regeneration in patients with labial bone plate defects. Materials and Methods: A total of 46 implants were immediately placed into anterior maxillary fresh sockets with buccal bone defects. Jumping space and the outer side of buccal defects were densely filled with hydroxyapatite bioceramics and covered with biomembrane. CBCT was performed immediately after surgery (T1), 6 months later (T2), and after 5 years (T3). Radiographs were taken at 1 month after surgery (RT1), definitive crown delivery (RT2), and once a year after prosthetic loading (RT3 to RT7) for 5 years. Pink esthetic score (PES) was evaluated at the time of definitive crown delivery (PT1) and at follow-up visits 1, 3, and 5 years (PT2 to PT4) after crown fixation. Results: No implants were lost during the observational period. The labial bone was radiographically reconstructed to acceptable volumes, with an average 2.86-mm horizontal bone and 2.2-mm vertical bone. Significant marginal bone loss occurred within 1 year after delivery of the definitive prosthesis. PES scores did not reveal inferior results at the 5-year follow-up. Conclusion: When other conditions are met for immediate implant placement, small labial plate defects (≤ 5 mm) will not affect the long-term esthetic effect.

Purpose: This preclinical comparison study assessed the diagnostic accuracy of low-dose CBCT protocols compared with standard-dose protocols in digital implant treatment planning and template-guided implant surgery.

Materials and methods: Thirty mandibles of pig cadavers underwent both CBCT protocols on an Orthophos SL Unit (Dentsply-Sirona). Surface scans of the regions of interest were performed to create a digital diagnostic wax-up followed by 120 subsequent implant plannings (one implant per quadrant). Simple randomization (1:1) was assessed to assign each quadrant into one of the imaging protocols. Sixty implant surgical guides were manufactured using CAD/CAM technology, followed by the fully guided placement of 60 implants following the surgical protocol in randomized order. Geometric accuracy between the planned and definitive implant position was determined regarding apical distances between the central axes and angle deviation. Descriptive statistics and linear regressions were used for the statistical analysis of the data.

Results: Regarding implant apex deviation using low-dose CBCT, the following differences were observed: apical deviation of 0.75 ± 0.63 mm and angular deviation of 2.5 ± 2.12 degrees, while the standard-dose CBCT showed the following results: apical deviation of 0.92 ± 0.55 mm and angular deviation of 3.06 ± 2.12 degrees. The regression analyses could not show evidence for a significant difference between the two CBCT protocols, neither with regard to the apical distance nor in view of the angular deviation.

Conclusion: Low-dose CBCT imaging protocols providing accurate 3D anatomical information with an improved benefit-risk ratio according to the as low as diagnostically acceptable (ALADA) principle could become a promising option as a primary diagnostic modality as well as for radiologic follow-up.

Objective: To determine the median event-free survival and relative complication rates of monolithic and minimally layered full-arch zirconia prostheses, as well as to identify risk factors for prosthesis complications. Materials and Methods: In this retrospective cohort study, a total of 129 subjects (173 prostheses) were included in the chart review and 56 subjects (75 prostheses) participated in a clinical follow-up visit. All subjects had either single- or dual-arch monolithic or minimally layered zirconia implant-supported prostheses. Data related to patient, implant, and prosthesis factors were extracted from charts. The subgroup that presented for a clinical visit were asked to complete a satisfaction questionnaire. For this subgroup, the following clinical measures were assessed: routine intraoral examination, number of occluding units, cantilever length on each side of the prosthesis (right and left), prosthesis height, occlusal scheme, and oral hygiene methods. Periapical radiographs were obtained when the last radiographs of the patient were taken more than 12 months prior. Results: The follow-up period ranged from 12 months to 7.1 years (mean: 1.9 years). Observed complications included implant loss, peri-implantitis, mucositis, purulence, sinus tract formation, oroantral communication, implant fracture, titanium base debonding, ceramic chipping, prosthetic screw fracture or loosening, damage to opposing teeth, and clicking sounds. There was an insufficient number of complications to evaluate the effect of covariates on the risk of specific complications, such as titanium base debonding (eight events), ceramic chipping (nine events), and peri-implantitis (eight events). The unadjusted event-free median survival time was 5.8 years. The proportion of all prostheses with at least one complication was 30%. There were no observed prosthesis losses during the follow-up period. Conclusion: Monolithic and minimally layered zirconia full-arch implant-supported prostheses demonstrate an acceptable median event-free survival time. Event-free survival times were increased and the number of complications was reduced in prostheses with five to eight implants and conventional (as opposed to zygomatic) implants. There was a reduced hazard of complications with a regular recall regimen. Patient satisfaction with these prostheses was high.

Purpose: To compare subjects' sensory responses to horizontal and vertical forces on tooth- and implant-supported restorations. Materials and Methods: In this prospective study, three protocols simulating the horizontal or vertical forces that occur during mastication were used to obtain subjective responses from subjects. These protocols included the measurement of horizontal force intensity during excursive movements and the identification of initial contact during guided and free vertical closure. Responses were recorded using a 1- to 10-point visual analog scale (VAS) and/ or monitored with electromyography (EMG) and Tekscan. Results: The study included 30 patients with a single implant-supported restoration (ISR) with a contralateral tooth-supported restoration (TSR). For horizontal forces similar to those of mastication (0.6 N), subject VAS scores were similar for both ISRs and TSRs at 6.3 vs 6.1, respectively. At reduced forces (0.2 and 0.4 N), subject responses were greater for the TSR at 3.4 and 5.4, respectively, as opposed to 1.2 and 2.6 for ISR, respectively (P < .01). During vertical guided closure (Test 1) at 25% of maximum bite force (MBF), subjects were more successful at correctly identifying initial contact of TSRs at a rate of 12 out of 17, compared to ISRs, which achieved a rate of 4 out of 13 (P < .1). In vertical free closure (Test 2), subject responses for the correct identification of initial contact at 50% MBF were similar for both TSRs and ISRs at 13 out of 17 and 9 out of 13, respectively. However, comparing the correct responses for subjects whose initial contacts were ISR showed a significant improvement in correct answers from Test 1 to Test 2, from 4 out of 13 correct to 9 out of 13 correct (P < .05). Conclusion: While the mechanism is not clear, subjects' ability to discern the horizontal and vertical forces at levels comparable to mastication appear similar between TSRs and ISRs.

Purpose: This study aimed to evaluate the deviations of implants with two different geometries placed with a bone-supported stereolithographic surgical template into the bone of Misch classification densities of D2, D3, and D4. Materials and Methods: Eight maxilla and eight mandible models were macrodesigned according to the jaw geometries. Bone densities of these models were created in parallel with the most frequently observed densities in the locations: D3 bone density in the anterior maxilla, D4 bone density in the posterior maxilla, D2 bone density in the anterior mandible, and D3 bone density in the posterior mandible. A bone-supported stereolithographic surgical template was prepared in accordance with the jaw models and planning and used to place 64 NobelParallel Conical Connection RP 4.3 × 13 mm and 64 NobelActive 4.3 × 13 mm implants on the models. Global deviation, lateral deviation, angular deviation, and depth deviation between planned and placed implants were calculated with Hypermesh. The Kruskal-Wallis test was used to analyze the differences between deviation data of the study groups, and the Mann-Whitney U test was used for pairwise comparisons of groups with significant differences. Significance was evaluated as P < .05. Results: The study groups showed statistical differences in terms of global, lateral, and depth deviation (P = .017, P = .044, and P = .012, respectively); no statistical difference was detected in terms of angular deviation (P > .05). When the data of all studies were evaluated, the deviation values for all maxillary and mandibular implants were examined regardless of bone and implant type; no statistical difference was found between the arches in terms of deviation type (P > .05). Conclusion: Regardless of the macrogeometry of the dental implants placed with the guide, no significant difference was observed between the deviation values of the different bone densities they were applied to.

Purpose: To evaluate the effect of chewing simulation and thermocyclic aging on the fracture resistance of CAD/CAM monolithic zirconia crowns supported by titanium and Ti-base abutments. Materials and Methods: Two implant abutment groups-titanium (Ti) and titanium base (Ti-base; Medentika)-were used. A total of 40 mandibular first molar CAD/CAM monolithic zirconia crowns (Vita YZ T) were fabricated, then cemented onto the abutments with Panavia V5. Each abutment group was divided into two subgroups (n = 10). The Ti and Ti-base groups were subjected to a single load until fracture, and the Ti/CT and Ti-base/CT groups (CT: chewing simulation and thermocyclic aging) underwent chewing simulation (1.2 × 10⁶ cycles × 50 N load, 1.4 Hz) and thermocylic aging (3,911 cycles/5°C to 55°C). The fracture resistances of the crowns were tested with a universal testing machine (1 mm/minute). Shapiro-Wilk and one-way ANOVA test were used for statistical analysis (P = .05). Results: The survival rates after chewing simulation and thermocyclic aging were 100% for both CT groups. The fracture resistance values (mean ± SD) of the groups were as follows: Ti = 1,718.18 ± 331.06 N, Ti-base = 1,713.53 ± 233.24 N, Ti/CT = 1,664.82 ± 188.62 N, and Ti-base/CT = 1,551.28 ± 344.79 N. According to one-way ANOVA test results, there was no statistically significant difference between the four groups (P = .526). Conclusion: CAD/CAM monolithic zirconia crowns supported by Ti-base or titanium abutments were found to have sufficient fracture resistance in the treatment of an absent single posterior tooth. However, more in vitro and clinical studies are required to evaluate the long-term performance of Ti-base abutments and CAD/CAM zirconia crowns.