International Journal of Oral & Maxillofacial Implants最新文献

Purpose: To assess the thickness of the palatal bone wall of maxillary anterior teeth in relation to age, sex, and tooth type.

Materials and methods: A total of 100 CBCT images of patients ≥ 18 years of age were used. The thickness of the palatal bone at the maxillary canines and incisors was assessed perpendicular to the long axis of the teeth at three locations: 4 mm apical to the cementoenamel junction (CEJ; MP1), halfway between the CEJ and the root apex (MP2), and at the root apex (MP3).

Results: At the MP1 site, 96% of the maxillary anterior teeth had a palatal bone thickness of < 1 mm, with a mean thickness of 0.5 mm. At the MP2 and MP3 sites, 86% and 100% of the teeth had ≥ 1 mm bone thickness, and the means were 2 and 5 mm, respectively. There were no significant differences among the age or gender groups. Maxillary canines showed significantly greater bone thickness than maxillary incisors, particularly at MP2 and MP3 sites.

Conclusion: Most of the examined teeth had thin palatal bone at the MP1 measurement site, and maxillary canines showed significantly thicker palatal bone than maxillary incisors. This finding should be considered when treatment planning for immediate implants in the maxillary anterior segment.

Purpose: To evaluate a novel proof-of-principle technique of simultaneous bone regeneration and implant placement in severely damaged sockets.

Materials and methods: This study consisted of patients who required a single implant and presented with severe facial bone loss. Individuals were randomly assigned to either the immediate or delayed implant placement protocol. Socket reconstruction and simultaneous implant placement were performed through periosteal-guided bone regeneration. Implants were encased in a customized shield of autogenous cortical bone harvested from an adjacent site. Re-entry surgery was performed at 12 to 18 weeks. Peri-implant tissues and pink esthetics were assessed following established success criteria.

Results: Of the 34 patients treated, 28 patients-consisting of 15 women and 13 men with an average age of 50.8 ± 4.5 years-continued to the final follow-up. All individuals showed new facial cortical bone regeneration at second-stage implant surgery after an average healing time of 14.9 ± 2.2 weeks (range: 12 to 18 weeks). Implants remained stable after loading. Success rates were 100% at 12 months. Mean pink esthetic score (PES) was 7.8 ± 1.2 (range: 6 to 9 on a scale of 0 to 10). Linear regression analysis showed that provisionalization and attachment loss are independent risk factors affecting pink esthetics (P < .01). Mild and moderate/severe attachment loss decrease pink esthetic scores by 0.9 and 1.7 points, respectively (95% CI: 0.2-1.5; P < .01). The use of provisional restorations improves pink esthetic scores by 1.6 points (95% CI: 0.8-2.4; P < .001). A PES > 7 was four and five times more likely to be expected for delay and immediate implants, respectively, if the implant had a provisional restoration delivered post-second-stage (RR = 4 to 5; 95% CI: 1-31; P = .07; P = .02). Cramér's V test showed a strong association between lack of implant provisionals and low pink esthetic scores (≤ 7, value = 0.7; P = .02). Facial implant transparency at follow-up was absent, and all implants had a band of keratinized tissue > 2 mm.

Conclusion: Facial bone regeneration and simultaneous implant placement is feasible in severely damaged sockets through periosteal-guided bone regeneration after a short healing period following immediate or delayed protocols. The assisted regenerated intrasocket bone allows for functional implant stability. Adjacent tooth attachment loss and lack of implant provisionalization negatively impacts pink esthetics. The proposed approach decreases costs, morbidity, and treatment duration and eliminates the need for multi-stage approaches.

Purpose: To evaluate the effects of ultraviolet (UV) treatment and alendronate immersion on the osseointegration of dental implants and mucosal attachment of dental implant abutments using a mongrel dog model.

Materials and methods: A total of 48 sandblasted, large-grit, acid-etched (SLA) titanium dental implants and 48 machined surface healing abutments in four male mongrel dogs were prepared. Implants and healing abutments were divided into four groups (n = 12 per group). The control (CON) group did not undergo additional surface treatments. The UV group was treated with UV for 15 minutes, and the alendronate-immersed (AN) group was soaked in 10-3 M alendronate for 24 hours. The UV treatment and alendronate soaking (UVAN) group was treated with alendronate, followed by UV irradiation. All implants were placed in the mandible of mongrel dogs, and the animals were sacrificed at 4 and 8 weeks postoperatively. Bone-to-implant contact (BIC), bone density, and connective tissue attachment were measured.

Results: In cortical bone, the UV group exhibited significantly higher BIC compared to the CON and AN groups (P < .05). In contrast, the AN and UVAN groups did not have significantly higher BIC. In the trabecular bone, there was no statistical difference between the groups. No significant increase in bone density and connective tissue attachment was shown in any group.

Conclusion: UV treatment of SLA surface implants significantly increased osseointegration in cortical bone. The alendronate immersion did not increase osseointegration, and there was no synergic effect with UV treatment. Further, UV treatment and alendronate immersion of machined healing abutments did not significantly increase connective tissue attachment.

Purpose: To analyze the quality of bone regeneration in fresh sockets using four different materials at different time points.

Materials and methods: A split-mouth randomized clinical trial was designed to evaluate the histologic and histomorphometric characteristics of 82 fresh sockets from 30 patients. One socket per patient healed spontaneously (control), and at least one fresh socket was grafted with a material chosen randomly from a sealed envelope: plateletrich growth factor (PRGF; n = 20 sites), PRGF + autologous bone (n = 9 sockets), autologous bone (n = 10 sites), or PRGF + demineralized freeze-dried bone allograft (DFDBA; n = 13). Biopsy specimens were taken at different time points divided into three assessment groups: short duration (2 to 4 months), intermediate duration (5 to 6 months), and long duration (7 to 12 months). The histologic findings were assessed to quantify the trabeculae pattern, the degree of mineralization, and the quality of bone regeneration.

Results: A total of 26 patients with 73 sockets completed the study. Mineralization after a short duration was found to be significantly higher among sockets treated only with autologous bone (47.3% ± 3.6%) or with PRGF+autologous bone (45.1% ± 13.6%). During the intermediate time point, this difference was not observed; also, the control sites were found to have the highest amount of mineralization (37.7% ± 14.9%). After a long duration of wound healing, the PRGF+DFDBA group had the greatest percentage of mineralized tissue (54.7% ± 28.7%), which was significantly higher than the sites treated only with PRGF (30.0% ± 13.2%).

Conclusion: From a histologic point of view, the use of autologous graft with or without PRGF seems to be the best strategy for socket regeneration within a short period of time (2 to 4 months). However, the application of PRGF alone inside fresh sockets may interfere with normal bone healing compared with control sites healed spontaneously.

Purpose: The purpose of this study was to evaluate the impression accuracy of two implants placed in different orientations and compare the impression accuracy obtained with the dual-arch impression technique using hybrid impression copings and the conventional open-tray impression technique.

Materials and methods: Five mandibular dentiform models were prepared by placing implants in the second premolar and second molar regions in the following different orientations: parallel to each other; 15-degree mesiodistal angulation; 30-degree mesiodistal angulation; 15-degree buccolingual angulation; and 30-degree buccolingual angulation. After making 10 impressions for each model with the open-tray impression technique and dual-arch impression technique with hybrid impression copings, cast models were fabricated for each impression (n = 10). Scan bodies were mounted on the five dentiform models and the fabricated 100 cast models were scanned using a desktop scanner. The three-dimensional deviation of the scan bodies on the cast models was calculated and compared to the reference data from the dentiform models. A two-way analysis of variance was conducted (α = .05).

Results: The root mean square deviation values obtained from the implants placed with 30-degree mesiodistal angulation were 93.05 ± 6.21 μm with the open-tray impression technique and 104.01 ± 8.89 μm with the dual-arch impression technique, which were the largest deviation values for both techniques (P < .001). Compared to the open-tray impression technique, the dual-arch impression technique with the hybrid impression copings showed significantly lower accuracy when the angulation between the implants was 15 degrees mesiodistally (P < .001), 30 degrees mesiodistally (P = .016), or 30 degrees buccolingually (P < .001). However, there was no significant difference between the accuracy of the two impression techniques for parallel implants (P = .74).

Conclusion: When the two implants were inclined 30 degrees mesiodistally, both implant impression techniques showed the largest deviation and the dual-arch impression technique showed lower accuracy compared to the conventional open-tray impression technique. Parallel placement of implants may improve impression accuracy and enable use of the dual-arch impression technique.

Purpose: To compare the 3D accuracy of copy dentures fabricated using an IOS (IOS copy denture) to that of copy dentures fabricated using the conventional method (conventional copy denture).

Materials and methods: Maxillary and mandibular complete dentures were fabricated and scanned using a high-precision dental laboratory scanner to obtain data (basic data). Optical impressions of the dentures were recorded with the IOS to obtain data (IOS reference dentures). The IOS copy denture was fabricated using a 3D printer after configuring the data using the software. The conventional copy dentures were fabricated by making impressions of the complete dentures and pouring the room-temperature curing resin into them. The IOS copy dentures and conventional copy dentures were scanned using a high-precision dental laboratory scanner to obtain data. The data obtained were imported into 3D analysis software, and the IOS reference denture, IOS copy denture, and conventional copy denture data were each superimposed on the basic data for 3D evaluation by color mapping and calculation of the concordance rate.

Results: Statistically significant differences in the concordance rates were observed between the IOS reference dentures and IOS copy dentures and between IOS copy dentures and conventional copy dentures (P < .05), but not between maxillary and mandibular complete dentures (P > .05).

Conclusion: The IOS copy dentures demonstrated greater accuracy than the conventional copy dentures.

Purpose: To evaluate patient satisfaction and prosthetic complications of maxillary conventional dentures and implant overdentures opposing mandibular implant overdentures with different attachments.

Materials and methods: A total of 60 patients with maxillary conventional dentures (maxillary CD) and mandibular two-implant overdentures received four implants in the maxilla. The implants were connected to the maxillary overdentures with a stud attachment (maxillary OD). The participants were classified into three groups according to the type of mandibular overdenture attachment: bar overdentures (BOD, n = 20), resilient telescopic overdentures (TOD, n = 20), and resilient stud/Locator overdentures (LOD, n = 20). Patient satisfaction (using a visual analog scale [VAS] and oral health-related quality of life (OHRQoL)] and prosthetic/soft tissue complications were evaluated for maxillary CD and maxillary OD after 1 year of insertion.

Results: LOD showed higher VAS and oral health impact profile (OHIP-14) scores with maxillary CD and maxillary OD than BOD and TOD except for ease of chewing (VAS) and satisfactory diet (OHIP-7). For maxillary CD, TOD showed a significantly higher frequency of prosthetic and soft tissue complications than BOD and LOD. For all groups, maxillary OD showed significantly higher patient satisfaction regarding VAS and OHIP-14 scores, and lower prosthetic and soft tissue complications than the maxillary CD.

Conclusion: Locator-retained maxillary overdentures opposing mandibular implant overdentures improved patient satisfaction and reduced prosthetic complications compared to conventional maxillary dentures. Such overdentures are best opposed by Locator-retained mandibular overdentures, as they increase patient satisfaction and reduce prosthetic and soft tissue complications compared to the bar and telescopic attachments.

Purpose: To identify the impact of residual bone height on 5-year implant survival and prosthetic complication rates in patients who underwent maxillary sinus grafting.

Materials and methods: A total of 87 consecutive patients were treated with 104 lateral approach maxillary sinus floor augmentation procedures with 100% deproteinized bovine bone and received 169 implants. The analysis considered patient age, sex, time of implant placement, and residual bone height. Patients with < 3 mm residual bone height were assigned to the study group; otherwise, they were placed in the control group.

Results: The mean follow-up was 68.2 months (0 to 103 months). The mean residual bone height was 1.8 mm in the study group and 4.1 mm in the control group. The 5-year implant survival and prosthetic complication rates were, respectively, 97.4% and 8.0% in the study group and 100% and 12.5% in the control group. Residual bone height, sex, age, and time of implant placement were not significant factors for the 5-year implant survival or prosthetic complication rate. The lateral bone wall was significantly thinner in the study group. The grafted bone height reduction was significantly different at 6 months and 2 years postoperation in both groups, but there was no difference in the change in grafted bone height reduction over time between the two groups.

Conclusion: A residual bone height < 3 mm did not impact the survival rates of implants placed in grafted maxillary sinuses or the prosthetic complication rate after 5 years of functional loading.

Purpose: This research aimed to evaluate the stress and fatigue generated in short implants compared to regular implants in rehabilitation with fixed full-arch implant-supported prostheses in atrophic mandibles using the finite element method (FEM).

Materials and methods: Four models were constructed with different implants lengths: 4, 6, 8, and 10 mm. A 100-N oblique load was applied to evaluate the stress on the bone, implant, and prosthetic components.

Results: Similar behavior was observed for all groups, except for 4 mm, which showed more discrepant values. During the fatigue test, all the groups exhibited infinite lives except G4.

Conclusion: Based on the similarity of all the models, it is suggested that all short implants investigated are seemingly viable alternatives for the rehabilitation of atrophic mandibles. However, the 6-mm-long and 8-mm-long implants evinced more favorable mechanical behavior than the 4-mm-long type.