Journal of Oral Implantology最新文献

The aim of this study was to evaluate the mechanical behavior of UCLA and Mini-conical abutments for implants with Tri-channel connections regarding torque loss and vertical misfit. Twenty 3-element metal-ceramic fixed partial dentures (FPD) supported by 2 implants were manufactured and divided into 2 groups (n = 10): UCLA (group 1) and Mini-conical Abutments (group 2). The evaluation of torque loss was carried out before and after mechanical cycling, while the vertical fit was evaluated throughout the different stages of manufacturing the prostheses, as well pre- and postcycling (300,000 cycles, 30 N). Statistical analyses of torque loss and vertical misfit were performed using the linear mixed effects model. Both groups showed torque loss after mechanical cycling (P < .05); however, there was no significant percentage differences between them (P = .795). Before cycling, the groups showed a significant difference in terms of vertical misfit values (P < .05); however, this difference was no long observed after cycling (P = .894). Both groups showed torque loss after the cycling test, with no significant difference (P > .05). There was no significant difference in vertical misfit after mechanical cycling; however, in group 1 (UCLA) there was accommodation of the implant-UCLA abutment interface, while group 2 (Mini-conical abutment) did not show changes in the interface with the implant after the test. Both groups behaved similarly regarding the torque loss of the prosthesis retention screws pre- and postmechanical cycling, with greater loss after the test.

Ingestion or aspiration of dental implant screwdrivers or implant components is potentially life-threatening. There are no reports on the frequency at which dentists drop these devices within the mouth or which components are most problematic. There are few reports on what protective measures clinicians take, where risks exist, and how this problem is managed. A 9-part questionnaire was provided to dentists. Data collected included clinicians’ roles, implant surgeons, restorative clinicians, or both—the frequency of dropping implant screwdrivers or components, items considered most problematic. Patient protection and management were also requested. Finally, questions related to how much of a problem clinicians considered this to be and if further solutions and a standardized management protocol should be developed. One hundred twelve dentists voluntarily completed the survey. Of the dentists, 54% restored, 37% restored and surgically placed, and 9% solely placed implants. Twenty-nine percent claimed never to drop components, with 56% dropping an instrument less than 10% of the time. Less than half would suggest patients seek medical advice if a screwdriver or component was accidentally dropped intraorally and was not recovered. Thirty percent never tied floss tethers to screwdrivers, and a similar percentage reported they only sometimes did so. Throat pack protection was reported 51% of the time. Ninety percent considered dropping components an issue, with screwdrivers most problematic. Aspiration or ingestion of implant screwdrivers and components is problematic, with dentists varying their use of protection devices. There is a need to standardize and implement patient protection procedures and management and develop methods to reduce the risk of these potentially life-threatening issues.

Alveolar bone quality at the implantation site affects the initial stability of dental implant treatment. However, the relationship between bone quality and osseointegration has yet to be evaluated. Herein, we aimed to investigate the effect of bone quality on dental implant stability in osseointegration formation changes. Patients underwent computed tomography imaging before dental implantation at the posterior. Hounsfield units were measured at the platform, middle, and tip sites. Implant stability was measured using resonance frequency analysis immediately and at 3 months postoperatively, in which the difference in implant stability quotients (ISQ) was defined as the change between primary and secondary fixation. In multiple regression analysis, the dependent variable was the change between the immediate and secondary fixations. We included 81 implants that conformed to the criteria. Primary fixation yielded the following results: R² = 0.117, F = 2.529, and P = .047. The difference between the maxilla and mandible of the implantation site (P = .02) and the platform-site Hounsfield units (P = .019) were identified as significant factors. The following results were obtained regarding the change between the immediate and secondary fixation: R² = 0.714, F = 40.964, and P < .001. The difference between diameter (P = .008) and the immediate ISQ (P < .001) were identified as significant factors. Overall, the bone quality of the implantation site affected initial fixation; however, it had limited effect on secondary fixation. Our findings clarified the period where bone quality affects dental implant treatment and is expected to advance dental implant treatment.

The goal of this clinical report was to present an alternative to traditional flat bone reduction guides, using a custom-designed 3-dimensional (3D)–printed guide according to the future gingival margin of the planned dentition. A 61-year-old woman with concerns regarding her smile appearance was presented. The initial examination revealed excessive gingival show accompanied by excessive overjet. The dentition was in a failing situation. The proposed treatment plan, relying on the sufficient amount of bone and keratinized tissue, consisted of recontouring of the alveolar ridge and gingiva and placement of 6 implants and an FP-1 prosthesis after extraction of all remaining maxillary teeth. Digital smile design was completed, and a fully digitally guided surgery was planned. This consisted of using 3 surgical guides, starting with the fixation pin guide, continuing with the scalloped hard- and soft-tissue reduction guide, and finally the implant placement template. Following the surgery, the patient received a temporary restoration, and on the 4-month follow-up, a new polymethyl meta-acrylate temporary prosthesis was delivered. The patient’s 7-month follow-up is presented in the article. The report of this triple-template guided surgery indicated that digital 3D planning is a considerably predictable tool to properly establish and evaluate future occlusal plane, smile line, and lip support. Scalloped guides seem to be an excellent alternative to conventional bone reduction guides since they require less bone removal and improve patient comfort during surgery.

Achieving adequate primary stability for dental implants in the posterior maxilla is challenging due to the area's low bone density and fine trabecular bone. Low primary implant stability can compromise the long-term success of the implant. This study aims to evaluate the effect of intentionally undersized osteotomy sites on the insertion torque of implants placed in type 4 bone density in the posterior maxilla, regardless of the surgeon's tactile sense of the bone density. The conventional implant placement technique was performed in the posterior maxilla by intentionally omitting the last drill of the recommended drilling sequence protocol. The insertion torque was measured using an integrated surgical motor software. The study included 72 implants in patients of both genders and different age groups. The retrieved samples were divided into four groups, with insertion torque ranging from 11 Ncm to 48 Ncm. The mean insertion torque was 26.51 ± 0.18 Ncm for all cases (P = .001). No significant difference was found in the mean insertion torque between different age groups (26.51 ± 2.845, P = .84). However, a significant difference was observed between male and female cases (P = .84). Most implant insertion torque measurements vary significantly between cases in the intentionally underprepared posterior maxillary osteotomy site. The last drill should be omitted for all preparations of the posterior maxillary implant sites. Intentionally minimizing the osteotomy site is recommended for all posterior maxillary implant cases.

Reports of implant fixtures dislocating into the maxillary sinus during sinus graft procedures are well-documented. However, cases of fixtures migrating into the sinus long after placement have yet to be reported. This case report details the surgical extraction of a displaced screw and cement-retained prosthesis, including a fixture and its abutment, from the maxillary sinus after a minimum of 5 years under functional load. The extracted implant was subsequently examined using scanning electron microscopy and energy-dispersive x-ray spectroscopy. We found that the migration commenced with peri-implantitis surrounding the implant, replacing the second molar. This was accompanied by a loss of cement from the crown on this implant and concurrent loosening of the abutment screw on the implant, replacing the first molar. We hypothesize that the inability of the bony tissue surrounding the second molar implant to withstand occlusal forces resulted in forming a bony sequestrum. This process ultimately precipitated the migration of the fixture, along with its abutment and adjacent necrotic bone, into the sinus cavity.

Although a smaller size field of view (FOV) of cone-beam computerized tomography (CBCT) reduces radiation exposure, its effect on the accuracy of static computer-aided implant surgery (s-CAIS) remains unknown. This study aimed to evaluate the impact of the size of FOV on the accuracy of s-CAIS and to investigate if the arch affects this effect. A total of 32 implant sites on 8 identical scannable models (maxillae and mandibles) were randomly allocated to 2 FOV sizes: test (5 × 5 cm) and control (10 × 10 cm). All models were scanned with an intraoral scanner (IOS). With the registration of the surface scan and CBCT image, a prosthetic-driven implant position was planned. Following the fabrication of surgical templates, a single-blinded surgeon placed all implants with the fully guided s-CAIS protocol. IOS captured the implant positions with the scan body attached. Implant-planning software measured the angular deviation, 3-dimensional (3D) deviation at the crest, and 3D deviation at the apex between preplanned and actual implant positions. Two-way analysis of variance was used to analyze the effect of FOV and arch on the deviations. The size of FOV did not show a significant effect (P > .198) on angular deviation, 3D deviation at the crest, or 3D deviation at the apex. No significant difference was found when comparing the effect of the size of FOV between the maxillary and mandibular implants. In conclusion, the use of small FOV CBCT demonstrated comparable accuracy of s-CAIS to the use of medium FOV CBCT.

This report of cases aims to share our treatment experiences in 4 sinus graft infection cases after sinus floor elevation and simultaneous implant placement. The preoperative and postoperative intraoral and radiographic photographs were collected and used to assess the treatment outcomes. The sinus cavity status, bone augmentation results, and implant stability were used as measurements to determine the treatment effectiveness. Four patients received partial graft removal as their surgical treatment for sinus graft infection combined with antibiotic therapy, with or without immediate secondary grafting. After early intervention, antibiotic therapy, and partial debridement of the infected sinus grafts, radiographic and clinical outcomes indicate successful resolution of the graft infection and stable bone graft levels around the implants. The keys to the successful management of the sinus graft infection were: early detection of the infection; early intervention, including partial debridement of the infected graft particles; and antibiotic therapy.

The aim of this study was to evaluate the radiographic and clinical outcomes of patients undergoing sinus membrane elevation via a minimally invasive crestal approach utilizing the dental implant. Twenty patients having 1 or more missing posterior teeth were included. The maxillary sinus membrane was elevated using dental implant via a crestal approach in areas with insufficient residual bone. CBCT scans were used to measure the amount of newly formed bone, implant length inside the sinus, bucco-palatal sinus width, and bone thickness. Surgical and postsurgical complications along with implant survival were also measured. The mean (±SD) values for the newly formed bone after 1 year were 2.4 (±1.87) mm, while values for implant length inside the sinus were 4 (±1.49) mm. The results showed that percentage of implant length inside the sinus and the palatal bone thickness were statistically significant positive predictors of the newly formed bone. Higher percentage of implant length inside the sinus and increased palatal bone thickness were associated with larger amounts of newly formed bone. A high patient satisfaction was reported along with a 100% implant survival. The utilization of the novel dental implant approach for crestal sinus elevation demonstrated predictable clinical and radiographic outcomes. This novel technique is simple to both patients and clinicians, rendering it a promising and cost-efficient procedure.

Accuracy is a necessity in implant impressions to fabricate accurately fitting implant-supported prostheses. This in vitro study aimed to explore the impact of the number of scan bodies on scanning quality by comparing scans of 2 vs 4 implants, and to determine if their accuracy and precision meets acceptable clinical threshold. Two mandibular edentulous models were used: one with 4-parallel implants (4-IM) and the other with 2-parallel implants (2-IM). Each model was scanned 10 times with an intraoral scanner, while reference scans were obtained with a high-precision laboratory scanner. The accuracy of test scans was evaluated by superimposing them onto reference scans and measuring 3D and angular deviations of the scan bodies. To assess the precision, the repeatability of the scans was analyzed by measuring the 3D SDs. Independent t test was used to compare angular deviations, the Mann-Whitney U test was used for 3D deviations and 3D SDs, and 1 sample t test was used for comparing means to the clinical threshold. Angular and 3D deviations were statistically not significant between the 2 groups (P = .054 and 0.143). 3D deviation values were higher than the 150-µm threshold for 2-IM (201 µm) and 4-IM (290 µm); angular deviation in 2-IM was 0.600 degrees and 0.885 degrees for 4-IM. There was no statistically significant difference in the precision of scans between the 2 groups. (P = .161). Although scanning quality improved when 2 scan bodies were used, the difference was not statistically significant. Moreover, full-arch implant scanning did not meet acceptable levels of accuracy and precision.