International Journal of Oral & Maxillofacial Implants最新文献

Purpose: To examine the stresses caused by different All-on-4 surgical techniques-conventional, a combination of monocortical and bicortical, bicortical, and nasal floor elevation-on the implant and the surrounding bone using 3D finite element analysis (FEA).

Materials and methods: A 3D bone model of the atrophic maxilla was created based on CT imaging of the fully edentulous adult patient. All implants used in the models were 4 mm in diameter, and the length was 13 mm in the anterior and 15 mm in the posterior. Implants were applied to four different atrophic maxillary models with the All-on-4 technique: anterior and posterior monocortical implants in the first model, anterior monocortical and posterior bicortical in the second model, anterior and posterior bicortical in the third model, and anterior and posterior bicortical with nasal floor elevation in the fourth model. Eight linear analyses were performed by applying force from both vertical and 45-degree oblique directions to the four models prepared in our study.

Results: When the cortical and cancellous bone around the anterior implants was examined, it was observed that the oblique and vertical loading conditions and the stresses around the implant were similar in all models. When the posterior implants were examined, model 1 (ie, anterior and posterior monocortical implants) showed the greatest oblique compression, vertical compression, and vertical tension forces. According to the Von Mises stress (VMS) analysis results for anterior and posterior implants, higher values were observed in model 1 compared to models 3 and 4 under oblique and vertical forces. It was observed that bicortical placement of the implants reduced the stresses on the bone and implant-abutment system but had no significant effect on the stress on the bar.

Conclusions: According to the results of our study, in the All-on-4 technique, bicortical placement of the implants reduced the stresses on the bone and implant when the anatomical limitations allowed. In addition, nasal floor elevation can be applied in the atrophic maxilla in appropriate indications.

Purpose: To assess the peri-implant and flap parameters of the prefabricated microvascular fibula flap and determine the dental implant survival rate.

Materials and methods: This retrospective study investigated a cohort of subjects who received prefabricated microvascular fibula flaps at two highly specialized tumor reconstruction centers. The subjects had all suffered atrophy or a large segmental defect of the jaws due to tumor resection or injury. Two independent surgeons determined the dental implant survival rate and assessed the peri-implant parameters and flap parameters during clinical follow-up.

Results: In total, 41 subjects were treated with a prefabricated fibula flap between 1999 and 2012. Of these, 17 subjects (10 male, 7 female) with a total of 62 dental implants were examined. The other 24 subjects were unavailable for assessment and had to be excluded. Ten of the 62 dental implants (16.1%) had to be removed due to peri-implantitis before the follow-up assessment. Follow-up assessments were performed at intervals ranging from 2 to 12 years (mean: 7.2 years) after fibula flap transplantation. The dental implant survival rate was found to be 83.9%. A total of 208 dental surfaces were assessed. Overall, 96% of all surfaces had a pocket depth (PD) of ≤ 4 mm and 4% had a pocket depth of > 5 mm. An attachment level (AL) of 3 mm was measured in 48.5% of implants and ≥ 5 mm was measured in 15.9% of implants. Dental implants with a PD > 4 mm showed a significantly higher plaque index (PI) (75%; P = .0057), papillary bleeding index (PBI) (62.5%; P = .0094), and radiologic bone loss (P = .0014) compared to dental implants with a PD ≤ 4 mm.

Conclusions: Reconstructive surgery using microvascular fibula flaps represents an alternative tool for oral rehabilitation in subjects suffering from a large segmental defect in the maxillary or mandibular bone compared to the conventional method. However, it appears that the different ossification processes that develop the fibula and the jawbones affect dental implant survival.

Purpose: To validate guided surgery for zygomatic implants (ZIs) by analyzing the final position of the implants relative to the preoperatively planned position. Material and Methods: Five patients with fully edentulous atrophic maxillae treated with four ZIs through a fully guided implant surgical approach were evaluated. The preoperative phase included digital planning, through which the surgical guide was designed and created. Analysis of the guided surgery accuracy was carried out by superimposing the digital planning over the final position of the implants using preoperative and postoperative CBCT. The radiologic evaluation included implant angular deviation, entrance deviation, exit deviation, platform deviation, and apex apicocoronal and mesiodistal deviation. Results: All five patients (two men and three women; mean age: 61.8 ± 3 years) were each treated with four ZIs using a fully guided approach with an extrasinusal path, obtaining ideal emergence of the implants. Superimposition comparison found a mean axial angular implant deviation of 0.79 ± 0.41 degrees and a mean implant entrance deviation of 0.95 ± 0.26 degrees. The platform deviation was 0.62 ± 0.19 mm buccopalatally and 0.76 ± 0.14 mm mesiodistally, while the apical deviation was 0.42 ± 0.13 mm buccopalatally and 1.06 ± 0.37 mm mesiodistally. Conclusions: Guided surgery in zygomatic implants appears to be sufficiently accurate to make it a safe and predictable technique.

Purpose: To assess the literature comparing histologic levels of osseointegration for titanium vs zirconia dental implants. Materials and Methods: This systematic review was conducted following the PRISMA guidelines and was registered in PROSPERO (CRD42021236781). Electronic and manual searches were carried out through the PubMed/MEDLINE, PubMed Central, and Embase databases with a platform-specific search strategy combining controlled terms (MeSH and Emtree) and text words. The articles were selected by two independent investigators who evaluated the articles based on the criteria for eligibility. Results: A total of 17 articles were included. All were preclinical studies. The populations included dogs (27.55%), minipigs (14.28%), rats (14.28%), and rabbits (43.89%); and the implantation site varied among the mandible (36.82%), maxilla (9.04%), tibia (17.64%), skull (10.70%), and femur (25.80%). A total of 370 titanium (Ti) implants and 537 zirconia (Zr) implants were evaluated. The average osseointegration (% bone-to-implant contact) for Zr was 55.51% (17.6% to 89.09%), and for Ti was 58.50% (23.2% to 87.85%). There was no statistical difference between studies at the 2-month follow-up (P = .672), but this difference was significant at 1 and 3 months (P < .001). Conclusions: Within the limitations of this review, Zr implants had a similar level of osseointegration compared to Ti implants. Nonetheless, because these findings are based on preclinical research, all data must be carefully examined.

Purpose: To determine the optimal implant diameter under limited bone width by comparing the effects of implants with different diameters on implant stability, peri-implant bone stability, and osseointegration. In addition, to evaluate the reliability of resonance frequency analysis (RFA) in detecting osseointegration and marginal bone level (MBL). Materials and Methods: Mandibular premolars and first molars of seven beagle dogs were extracted. After 8 weeks, their mandibular models and radiographic information were collected to fabricate implant templates. Implant sites were randomly divided into three groups according to diameter: Ø3.3, Ø4.1, and Ø4.8 mm. Implant stability quotient (ISQ) measurement and radiographic evaluation were performed after surgery (baseline) and at 4, 8, and 12 weeks. Three dogs were euthanized at 4 weeks to observe osteogenesis and implant-tissue interface biology. Four dogs were euthanized at 12 weeks to observe osseointegration. Hard tissue sections were prepared to analyze osteogenesis (fluorescence double labeling) and osseointegration (methylene blue-acid fuchsin staining). Results: At baseline and at 4, 8, and 12 weeks, the ISQ values of Ø4.1- and Ø4.8-mm implants did not differ (P > .05), but both had higher values than the Ø3.3-mm implants (P < .05). The mean marginal bone resorption (MBR) associated with Ø3.3-, Ø4.1-, and Ø4.8-mm implants was 0.65 ± 0.58 mm, 0.37 ± 0.28 mm, and 0.73 ± 0.37 mm, respectively. The buccal MBR of Ø4.8-mm implants was significantly higher than that of Ø4.1-mm implants (P < .05). The bone-to-implant contact (BIC) percentage at 12 weeks did not differ for any group (P > .05). The correlation coefficients between the ISQ and MBL of the Ø3.3-, Ø4.1-, and Ø4.8-mm implants were -0.84 (P < .01), -0.90 (P < .001), and -0.93 (P < .001), respectively, while that between the ISQ and BIC was 0.15 (P > .05). Conclusions: During the early healing stage, the performance of Ø4.1- and Ø4.8-mm implants in terms of implant stability was better than that of Ø3.3-mm implants. Implant diameter may not influence BIC percentage. RFA can be used to evaluate implant stability and MBL but is not suitable to assess the degree of osseointegration.

Purpose: To determine which clinical factors might affect the postimplantoplasty presence of residual threads, platform alterations, and level of surface roughness. Materials and Methods: A total of 60 implants were placed in 20 resin models (10 edentulous maxillary models and 10 partially dentate mandibular models), and 5-mm peri-implant bone defects were created. These models were then placed in simulation mannequins. A single researcher performed the implantoplasties, which were divided into the following groups: favorable situation (FS; maxillary incisors without adjacent teeth), unfavorable situation (US; mandibular molars with adjacent teeth), crown (C; mandibular premolars with a prosthetic crown and adjacent teeth), and noncrown (NC; mandibular premolars with adjacent teeth and without a prosthetic crown). The presence of residual threads, gaps in the implant-abutment interface, and silicone debris was assessed using a scanning electron microscope (SEM), and the surface roughness (Sa and Sz) was analyzed with a confocal optical microscope. A descriptive and bivariate analysis was conducted. Results: The postimplantoplasty surfaces were significantly smoother than the original implant surfaces. The surface roughness was significantly higher in the US group than in the FS group. Gaps in the implant-abutment interface were infrequent (6.67%; 95% CI = 2.62 to 15.93) and only appeared in the posterior zone. The odds ratio for the presence of residual threads and silicone debris (US group vs FS group) was 7.1 (95% CI = 4.15 to 12.14; P < .001) and 5.53 (95% CI = 3.21 to 9.53; P < .001), respectively. When a prosthetic crown was present, residual threads were 7 times more likely to be found (OR = 7.0; 95% CI = 3.5 to 13.99; P < .001). Conclusions: Implantoplasty leads to a significant reduction in the surface roughness of implants but is affected by several variables. Performing implantoplasty on posterior mandibular implants with adjacent teeth seems to be more challenging compared to implants placed in the anterior region of a fully edentulous maxilla. The presence of a prosthetic crown should also be considered as a relevant factor. Furthermore, implantoplasty can sometimes cause gaps in the implant-abutment interface and an accumulation of silicone debris, especially in areas with limited access.

Objective: To verify the effect of fiducial marker number and configuration on target registration error (TRE) for dynamic computer-aided zygomatic implant surgery. Material and Methods: All patients who underwent zygomatic implant surgery with navigation from January 2018 to December 2021 were enrolled. For each patient, 6 to 8 miniscrews were placed intraorally as fiducial markers before the surgery. After the registration procedure, the TRE, which represents the distance between the target of the image space and the real position of the fiducial markers, was calculated. SPSS (22.0) was used for statistical analysis. Results: A total of 325 titanium miniscrews were placed in 47 patients who underwent zygomatic implant placement by navigation. The lowest TRE was 0.2 mm, compared to the highest TRE of 1.9 mm. There was no significant difference in the mean TRE value among the different titanium miniscrew groups (P = .07). A total of 8 miniscrews in 7 patients were lost in the maxillary tuberosity area prior to and during navigation surgery, which resulted in an irregular polygonal distribution of fiducial markers. However, there was no statistically significant difference in TRE between a polygonal distribution (0.62 ± 0.35 mm) and an irregular polygonal distribution (0.68 ± 0.33 mm) (P = .35). Conclusion: A scattered, polygonal distribution with of a minimum of five fiducial markers in an edentulous maxilla could achieve acceptable TRE values in registration. It seems that the registration error was not influenced by the absence of one corner in a polygon distribution.

Purpose: To compare the stability of short vs standard (ie, regular-length) implants in the edentulous mandible. Materials and Methods: In this prospective clinical study, 20 patients with edentulous mandibles received four implants each-two short implants (4 mm) in the region of the first molar and two standard implants (≥ 10 mm) in the interforaminal region. Implant stability was assessed using resonance frequency analysis immediately after implant placement and at the day of the abutment connection after 3 months of healing in order to provide an implant stability quotient (ISQ). Results: Implant stability in the two implant groups at placement (ISQ: short 66.2; standard 68.2) and at abutment connection (ISQ: short 74.9; standard 75.7) did not differ substantially or statistically significantly (both P > .05). Findings did not change after statistically controlling for potential confounders such as bone quality and bone crest width. At abutment connection, 95% of the short and 97.5% of the standard implants demonstrated sufficient stability for conventional loading (P > .05). Conclusions: Short dental implants demonstrate similar primary and secondary stability compared to standard implants and seem to be a promising treatment option for rehabilitation of patients with edentulous mandibles.

Purpose: To compare the risk of sinus membrane perforation (SMP) among lateral window sinus floor elevation (LSFE) and transcrestal sinus floor elevation (TSFE) techniques in prospective and retrospective studies for patients who underwent sinus augmentation for dental implant placement. Materials and Methods: A database search was conducted to screen the literature published from January 1960 to August 2021. The associations between SMP and surgical techniques as well as other clinical factors were evaluated via network meta-analysis. The impact of SMP on vertical ridge gain and implant survival was also evaluated. Results: Eighty-five studies with 5,551 SFE procedures were included. In LSFE techniques, using rotary burs showed the highest risk of SMP (surface under the cumulative ranking area [SUCRA] = 0.0745). In TSFE techniques, using reamers had the lowest risk of SMP (SUCRA = 0.9444). Increased SMP prevalence was significantly associated with reduced implant survival rate (odds ratio [OR] = 0.45 per 10% increase of SMP rate [95% credible interval (CreI): 0.21, 0.71], P < .001). Conclusions: With the inherent limitations, this network meta-analysis suggested that some techniques within either the LSFE or TSFE group may reduce SMP risk. Additional randomized controlled trials and better assessment of SMP are required to directly compare the risk of SMP between LSFE and TSFE.