The International journal of oral & maxillofacial implants最新文献

Purpose: It is well known that the success of dental implants is directly related to bone quantity and quality. This experimental animal study aimed to evaluate the histological and radiological effects of autogenous blood (AB), advanced platelet-rich fibrin (A-PRF) and non-grafted following supported sinus floor elevation by resorbable membrane and ultrasonic-activated pin system.

Materials and methods: Twenty one sinus floor lifting procedures were performed in eleven New Zealand rabbits that were divided into three groups. Each group planned to include seven maxillary sinus regions. Resorbable membrane and ultrasonic-activated pins (SonicWeld Rx®, KLS Martin) were used to support the elevated sinus floor in all groups. After the elevation of the sinus floor, bone defects were supported with autogenous blood (Group 1), with A-PRF in (Group 2) and without using any material in the control group (Group 3). The rabbits were sacrificed at 8 weeks after surgery. Specimens obtained from the upper and lower regions. Radiographic and histologic examinations were performed on all samples. The radiologic examination was performed on new bone formation based on density difference (Grayscale/GS) in axial, coronal and sagittal planes on CBCT sections. Histologic evaluation was performed by analyzing new bone tissue percentage/score, inflammation and fibrous tissue parameters.

Results: In radiologic evaluation, the differences in GS values obtained in Group 3 in all planes were significantly lower than in Group 1 and Group 2, indicating significantly higher bone formation (p<0.05). In histologic evaluation, the percentage and score of newly formed bone were higher for Group 3; however, that difference was significant between Group 3 and Group 1 for the specimens taken from the upper regions (p=0.005 and p=0.018, respectively). Fibrous tissue formation was lower in Group 3; the difference was significant between Group 3 and Group 1 for the specimens taken from the upper regions (p=0.037). Inflammation values were similar between the groups.

Conclusions: New bone formation after sinus floor elevation without using graft material has been associated with more successful outcomes than the group using AB and A-PRF in terms of histological and radiographical parameters.

Introduction: The treatment of atrophic edentulous maxilla with implants becomes complex due to issues such as poor bone quality in the posterior region, insufficient bone volume, and anatomical constraints of the maxillary sinus. Rehabilitation using dental implants placed in the pterygomaxillary region posteriorly and between the maxillary sinuses anteriorly allows overcoming these limitations.

Purpose: The aim of this study is to investigate the stresses generated in the bone, implant, substructure materials, and aesthetic materials of hybrid prostheses prepared from three different substructure materials placed at different lengths in the pterygomaxillary region of completely edentulous maxillae using three-dimensional finite element analysis (FEA).

Material and methods: Implants of two different lengths, 11.5 mm and 18.0 mm, were placed in the pterygomaxillary region. The 18.0 mm long implant has bicortical anchorage. Hybrid prostheses were prepared using three different substructure materials: PEEK, Ti, and Zr. A force of 150 N was applied unilaterally at an angle of 30 degrees from the palatal direction to the buccal side.

Results: Models with PEEK substructures exhibited greater displacement and shear stress values compared to those with Ti and Zr substructures. An increase in Von Mises stresses was observed in the apical region of the 18 mm long dental implants where cortical anchorage was achieved. In cortical bone, higher Pmax and Pmin values were noted in certain areas of the models with PEEK substructures.

Conclusion: Different substructure materials have varying effects on the prosthesis, bone, and implant. It is suggested that the use of substructure materials with high elastic modulus would be more appropriate to reduce potential prosthetic complications in hybrid prostheses and achieve predictable stress distribution in the bone. The use of maxilla-restricted dental implants should be considered when sufficient cortical bone anchorage is present around the neck region of the implants. However, in cases where cortical bone support in the neck region is insufficient, the use of implants providing bicortical anchorage may be more beneficial.

Objectives: This study aims to evaluate the implantation accuracy of a novel eccentric surgical guide strategy for immediate implant placement (IIP).

Materials and methods: Two hundred CBCTs were used to measure anatomical parameters, and the obtained data were used to create an anatomical extra-oral model for IIP. Eccentric guides are specialized guides that position the drills or implant eccentrically toward the high-density side. Thirty implants were placed into fifteen anatomical models utilizing three different computer-assisted static implant surgery (sCAIS) protocols: the conventional, the one-step, and the step-by-step methods. Postoperative CBCTs were superimposed on the preoperative virtual placement plan to assess 3D and 2D deviations at the implant entry and apex point.

Results: The average angle between the model's inclined plane and the implant's central axis was 18.3°, ranging from 10° to 39°. The one-step eccentric method (Group B) had the smallest 3D deviation at the entry point (mean = 0.41 ± 0.14 mm), apex (mean = 0.68 ± 0.20 mm), and angular deviation (mean = 1.74 ± 0.68°). The 2D deviation analysis showed Group B had the lowest labial deviations at the entry (mean = 0.37 ± 0.16 mm) and apex (mean = 0.36 ± 0.29 mm). The step-by-step eccentric method (Group C) resulted in a considerable reduction in labial deviation at the apex (mean = 0.35 ± 0.39 mm).

Conclusion: The novel eccentric surgical guide strategy increased implantation accuracy in IIP, particularly by lowering labio-palatal discrepancies.

Clinical relevance: Implant position can be affected by the anatomical structure of the tooth extraction socket. Therefore, it is critical to find a novel eccentric surgical guide strategy to address labial deflection during implant site preparation for IIP.

Background: Two-piece zirconia implants offer a metal-free alternative to titanium implants, but only limited long-term data are available. The aim of this retrospective study was to evaluate the clinical outcomes of two different, identically designed two-piece zirconia implants (NobelPearl™ and Zeramex XT) in a private dental practice.

Material and methods: Between 2017 and 2024, 167 implants were placed in 106 patients and followed up to 88 months (Ø 39.1 months). In addition to the implant survival rate, marginal bone loss (MBL), clinical parameters and surface properties were examined using 3D profilometry. The statistical analysis included descriptive evaluations and a survival analysis using the life table method.

Results: Three implants were lost (two fractures, one failed osseointegration), corresponding to an effective survival rate of 98.2%. The mean marginal bone loss varied between -0.14 mm and -0.58 mm. The surface roughness was minimal (Sa ~0.5 µm). No risk factor showed a significant association with implant loss in the univariate analysis.

Conclusion: Two-piece, screw-retained zirconia implants showed a high survival rate and stable peri-implant tissue conditions over a period of up to seven years. They represent a promising metal-free alternative to titanium implants. Further prospective long-term studies are needed to validate these results and to better understand potential risk factors.

Purpose: To investigate the influence of low dose protocols through tube current reduction on two cone-beam computed tomography (CBCT) devices on the evaluation of bone graft loss adjacent to titanium and zirconium implants.

Materials and methods: Twelve titanium and twelve zirconium implants were placed in dry mandibles. Gaps of at least 2 mm were created around the implants and filled with bone graft. In half of the samples the graft was removed up to the third implant thread. Images were acquired in Eagle 3D and OP300 CBCT devices with different dose protocols (tube current from 4 to 12.5mA) and were evaluated by 7 observers. Diagnostic values were calculated and compared between implant material and dose protocols by two-way ANOVA (significance level 5%).

Results: For Eagle 3D, zirconium implants displayed lower diagnostic values than titanium, regardless of the protocol used (p<0.05), while protocols did not affect the diagnostic values (p≥0.05). For OP300, zirconium implants presented lower values (p<0.05) compared to titanium implants. Also, there is higher sensitivity for high dose protocol compared to the low dose protocol (p<0.05).

Conclusions: Implant material influences bone graft loss detection, with lower diagnostic values for zirconium implants. Low dose protocols can be effectively used for titanium implant assessment; however, high dose protocols may be required for bone graft loss around zirconium implants.

Purpose: In full arches, what is the accuracy of dental implants placed by means of static computer-assisted implant surgery (s-CAIS)?

Materials and methods: Two independent and calibrated reviewers selected studies based on pre-defined eligibility criteria and extracted data on study-, population-, intervention- and outcome (accuracy) characteristics. Risk of bias and the quality of evidence assessments of the included articles were performed by an independent and blinded reviewer. The meta-analysis was conducted using the random- effects model at a 5% significance level.

Results: Thirty (5 RCTs, 9 CCTs and 16 Case Series) studies were included. Overall, 2,056 implants distributed among arches in 416 patients (males n=161; females n=188; unclear n = 67) were assessed. Random-effects meta-analysis revealed statistically significant mean horizontal linear distortions at the implant neck and apex levels of 1.18mm (95% CI: 1.00 - 1.35) (p<0.001) and 1.46mm (95% CI: 1.22 - 1.69) (p<0.001), respectively, significant mean vertical linear distortion at implant depth level of 0.58mm (95% CI: 0.18 - 0.98) (p=0.113) and significant mean angular distortion of 3.65° (95% CI: 2.97 - 4.33) (p<0.001). Accuracy did not differ significantly between maxilla and mandible at all parameters assessed (p>0.05).

Conclusions: The accuracy of s-CAIS in full arches is within a clinically acceptable range and a 2-mm ho rizontal and 1-mm vertical safety margin should always be respected at planning.

Practical implications: A safety margin of 2 mm horizontally and 1 mm vertically in the planning for implant placement can ensure better results in full arches with reabsorbed bone.

Purpose: To evaluate implant success rates and facial mucosal profile changes in maxillary single immediate implant placement and provisionalization with the socket-shield (IIPP+SS) technique and without the socket-shield (IIPP-SS) technique.

Materials and methods: A total of 30 dental implants in 25 patients were assigned to either the IIPP-SS group (15 implants) or the IIPP+SS (15 implants) group. Clinical and radiographic outcomes were collected preoperatively (T0) as well as at 2-week (T1), 6-month (T6), and 12-month (T12) postoperative follow-ups. The implant success rate, marginal bone level changes, facial mucosal level changes, and papilla level changes were evaluated at different time points. Facial mucosal profile changes were assessed individually for hard and soft tissue zones and as a whole using volumetric analysis.

Results: Two implants were excluded (one patient dropped out and one implant failed) from the data analysis in this study, resulting in an overall implant success rate of 96.6% (28/29) after 1 year. Fewer facial mucosal profile changes were noted in the IIPP+SS group than in the IIPP-SS group; however, the difference was only marginally statistically significant (P = .06). No statistically significant difference was found in the facial mucosal level changes (P = .18) and papilla level changes (P = .67 for the mesial papilla level, P = .41 for the distal papilla level) between the IIPP-SS and IIPP+SS groups.

Conclusions: Within the limitations of this 1-year randomized controlled clinical trial, the IIPP+SS group appeared to maintain the implant facial mucosal profile slightly better than IIPP alone. Both treatment modalities provide clinically satisfactory outcomes biologically, functionally, and esthetically.

Purpose: To verify whether measuring the implant stability quotient (ISQ) at the abutment level is identical to the value obtained at the implant level.

Materials and methods: A retrospective clinical study and in vitro study were performed. For each study, the ISQ measured at the implant level defined the control groups. The values obtained after the abutment seating comprised the test groups, which were divided into three test subgroups corresponding to three different multiunit abutments: (1) straight multiunit abutments (MUAS) and (2) 17-degree angled multiunit abutments (MUA17), both with a 2.5-mm collar, and (3) 30-degree angled multiunit abutments (MUA30) with a 3.5-mm collar. Data was compared by the Wilcoxon signed-rank test and Kruskal-Wallis test.

Results: The control group (59 implants; 79.14 [SD = 3.39]) showed significantly higher measurements than the test group (73.22 [SD = 8.54]). In addition, the subgroup measurements from MUA17 (16 abutments; 66.38 [SD=1.20]) and MUA30 (16 abutments; 69.19 [SD = 0.96]) were lower than the control group. No differences were found in the MUAS (27 abutments; 79.67 [SD = 1.48]) subgroup when compared with the control group (correlation of 0.68). Regarding the in vitro analysis, the control group measurements (36 implants; 68.02 [SD = 1.81]) were significantly higher than the test group (62.57 [SD = 2.87]). The control group measurements were also higher than each test subgroup (12 abutments each): MUAS (65.44 [SD = 0.73]), MUA17 (60 [SD = 0.43]), and MUA30 (62.29 [SD= 0.35]).

Conclusions: Based on the results of this study, determining the ISQ at the abutment level results in lower ISQ values than the implant level; note that these measurements may not accurately reflect the actual implant stability. Future research is needed to explore whether and under what circumstances a correlation exists between the ISQ measured at the implant level and abutment level.

Purpose: To evaluate the survival rates and risk factors associated with resorbable blast media (RBM) surface dental implants.

Materials and methods: A total of 1,130 RBM surface implants with hybrid macrogeometry were placed in 260 patients, with a follow-up ranging from a minimum of 26 months to a maximum of 120 months. Implant survival and failure rates were analyzed over an average 60-month follow-up. Failure rates were examined based on implant length, patient sex, and sinus elevation procedures. Additional factors such as patient age, implant placement timing (immediate vs delayed), GBR, implant diameter, and implant location were assessed to determine their impact on long-term implant success.

Results: The overall survival rate for the implants was 94.4%, with most failures occurring within the first 12 months postoperatively. Male patients experienced significantly higher failure rates (7.36%) than female patients (4.0%). Short implants (8 mm) were particularly vulnerable to failure, with an 8.65% failure rate. Sinus augmentation procedures also presented an increased risk, with 10% failure for lateral sinus augmentation and 9.78% failure for crestal sinus elevation. In contrast, factors such as patient age, timing of implant placement, GBR, implant diameter, and implant location did not significantly influence failure rates. Notably, narrow-diameter implants (3.3 and 3.7 mm; n = 97) in the molar region did not increase the risk of failure, with only 5 experiencing failure. Failures after prosthetic loading were most common after about 3 years.

Conclusions: This study confirms the long-term viability of RBM surface implants, with high survival rates when early failures are mitigated. Short implants and sinus elevation procedures pose greater risks of failure, particularly in the early stages. However, simultaneous GBR and sinus elevation procedures did not significantly impact long-term outcomes, affirming the safety and efficacy of these complex interventions.