Journal of Oral Implantology最新文献

Purpose: This study analyzed the stress distributions on zygomatic and dental implants placed in the zygomatic bone, supporting bones, and superstructures under occlusal loads after maxillary reconstruction with obturator prostheses.

Materials and methods: 12 scenarios of three-dimensional finite element models were constructed based on computed tomography scans of a patient who had hemimaxillectomy. Two obturator prostheses were analyzed for each model. A total force of 600 N was applied from the palatal to buccal bones at an angle of 45°. The maximum and minimum principal stress values for bone and also the von Misses stress values for dental implants and prostheses were calculated.

Results: When zygomatic implants were applied to the defect area, the maximum principal stresses were similar in intensity to the other models; however, the minimum principal stress values were higher than in scenarios without zygomatic implants. In models that used zygomatic implants in the defect area, von Misses stress levels were significantly higher in zygomatic implants than in dental implants. In scenarios where the prosthesis was supported by tissue in the non-defect area, the maximum and minimum principal stress values on cortical bone were higher than in scenarios where implants were applied to both defect and non-defect areas.

Conclusions: In patients who lack an alveolar crest after maxillectomy, reduced stress on the zygomatic bone is expected if a custom bar-retained prosthesis is placed on the dental implant. The stress was higher on zygomatic implants without alveolar crest support than on dental implants.

Patient satisfaction and quality of life are integral to assessing oral health care quality. For many Americans still using conventional complete dentures (CD) or Implant Retained-Overdentures (IOD), it remains essential to consider improving their oral health outcomes and quality of life. Due to inexperienced student dentists providing dental care to dental school patients, patient grievances are generally considered a problem. Patient feedback and satisfaction have proven valuable resources for monitoring and improving patient safety. While CD and IOD are the two leading treatment options for edentulism, more comparative studies in the literature need to compare their outcomes in a school setting. The research question that guided this comparative analysis was, "Is patient satisfaction and quality of life affected by the type of prostheses and provider?" A validated questionnaire was mailed to 520 individuals selected from records of patients who had received treatment for edentulous mandible at a student prosthodontic clinic at the [redacted for peer review] from 2014 to 2016 with at least one year of follow-up time. A validated questionnaire for edentulous patients based on the Oral Health Impact Profile (OHIP-19) was used. In addition, information on patients' oral health-related quality of life, including questions related to the edentulous patients' satisfaction with their dentures, was collected. The response rate was 33% (N = 171). The study's findings confirm previous findings, suggesting that IODs may significantly impact oral health-related quality of life. Data show that 76% of the IOD group reported improvement in experience when using the implants to retain the mandibular denture. However, there were no statistically significant differences in the OHIP scores between overall CD and IOD patient groups. Males with IOD had lower physical pain, limitations, and concerns associated with a social disability and handicap domains. Comparing users who had experiences with both treatment options, this study discerned essential characteristics that contribute to increased patient satisfaction with IOD and identified significance in outcomes by gender. These findings guide prosthodontic practitioners' patient care practices and identify a continuing need to discuss CD and IOD treatment protocols within dental school curricula.

This study explored the average length of the incisive branch of the inferior alveolar nerve on cone-beam computed tomography (CBCT) regarding patient demographics in patients with edentulous mandibles. CBCT was utilized in a retrospective study of edentulous mandibles to assess the presence and anatomical variation for the incisive branch (IB). Three independent observers measured bilateral IB lengths. In addition to demographics, IB length and port of exit data were obtained. A one-way ANOVA was used to test IB length varied by sex or port of exit, and a standard Pearson's correlation was used to test for IB length and age significance with a significance level of a p-value<0.05. Intraclass correlation coefficients show significant agreement in IB length across all observers. No significant difference was noted between the exit port and IB length. An important effect was reported for sex, indicating women have generally shorter IB lengths (9.43 ± 3.99 vs 10.55 ± 3.92). There was a significant correlation with age, but the relationship was weak. Edentulous mandibles have an altered anatomic landscape and establishing predictive incisive branch dimensions aids practitioners in surgical planning.

After dental extraction a physiological phenomenon of reabsorption of the dentoalveolar process is triggered, especially if periradicular lesions are present, which can sometimes be associated with oro-antral communication in the upper posterior maxilla. With the aim of proposing a minimally invasive approach, 19 patients undergoing tooth extraction in the postero-superior maxilla were recruited. All cases presented an oroantral communication with a diameter of 2-5 mm after tooth extraction and the alveolar process, in some cases, with a partial defect of one or more bony walls. In these cases, a single surgical procedure was used to preserve the alveolar ridge with an open barrier technique with exposed d-PTFE membrane. The bottom of the extraction socket was filled with a collagen fleece and the residual bone process reconstructed using a bio-material based on carbonate-apatite derived from porcine cancellous bone. After 6 months all patients were recalled and subjected to radiographic control associated to an implant-prosthetic rehabilitation plan. Data relating to the sinus health status and the average height and thickness of the regenerated bone were collected. Radiographic evaluation verified the integrity of the maxillary sinus floor with new bone formation, detecting a vertical bone dimension between 3.1mm and 7.4mm (average 5.13mm ± 1.15) and a horizontal thickness between 4.2mm and 9.6mm (average 6.86mm ± 1.55). The goal of this study was to highlight the advantage of managing an oro-antral communication and, at the same time, to obtain the preservation and regeneration of the alveolar bone crest. The open barrier technique appears to be effective for the minimally invasive management of the oro-antral communication up to 5mm in diameter in post-extraction sites, with a good regeneration of hard and soft tissue.

The most difficult and time-consuming step in the free gingival graft (FGG) for keratinized mucosa augmentation is the compression suture anchoring the FGG to the periosteum. In this article, a novel "microscrew with tie-down sutures" technique was proposed to anchor the FGG to the recipient site without the traditional trans-periosteum suture. This patient's keratinized mucosa width (KMW) around the healing abutments of teeth #29 and #30 was less than 1 mm. After an apically positioned flap (AFP) was prepared, two microscrews were placed at the buccal plate of the alveolar ridge bone, which is the coronal margin of the AFP. Then, the sutures winded between the microscrews and the healing abutments to anchor the FGG. In conclusion, the "microscrew with tie-down sutures" technique offers a feasible and simple alternative for the trans-periosteum compression suture, particularly in situations when the periosteum is fragile, thin, or injured.

The stability of implant-abutment joint is fundamental for the long-term success of implant rehabilitation. The screw loosening, fracture, and head deformation are among the most common mechanical complications. Several surface treatments of titanium screws have been proposed to improve their resistance and stability. Diamond-like carbon (DLC) coating of the materials is widely used to increase their wear resistance and durability. The present study aimed to evaluate the effect of carbon fiber coating on the screw head on screw removal torque and screw head stripping. One hundred titanium implant screws were used, 50 without coating (Group 1) and 50 with DLC coating of the screw head (Group 2). Each screw was tightened with a torque of 25Ncm and unscrewed ten times. The removal torque was measured with a digital cap torque tester for each loosening. Optical 3d measurement of the screw head surface was performed by a fully automatic machine before and after multiple tightening to investigate surface modifications. The reverse torque values decreased with repeated tightening and loosening cycles in both groups without significant differences (p>0.05). Optical measurements of surface dimensions revealed average changes of 0.0357mm in Group 1 and 0.02312mm in Group 2, which resulted to be statistically significant (p<0.001). The DLC coating of the retention screw head can prevent its distortion and wear, especially after multiple tightening.

The present study aims to assess the feasibility of implant rehabilitation in kidney-transplanted patients. Patients with kidney transplantation included in periodontal supportive care and at least one year of dialysis with mono- or partial edentulism were eligible for this study. Histomorphometric evaluation of the harvested bone was matched with radiological bone assessment. Implant stability was also monitored with RFA and ITV. Fixed cemented prostheses have been delivered after conventional loading protocol. Supportive periodontal therapy has been administered. Eleven patients (9 males and 2 females) were included. The mean age was 58.1 ± 9.9 years. A total of 17 implants were inserted and analyzed. Mean ITV was 39.3 ± 23.8 Ncm. The mean primary stability (ISQ) at T0 was 71.7 ± 10.5, whereas the mean secondary stability at T1 was 73.0 ± 7.3. The minimum follow-up was 62 months, with a maximum of 84 months (7 years) reached by four patients. Fourteen out of 15 implants were in function at a 5-year follow-up (survival rate 93.3%). Two implants showed peri-implantitis. Seventeen bone samples were collected (13 in the mandible and 4 in the maxilla). The mean percentage of marrow spaces and lamellar bone was 41.6% and 58.4%, respectively. Class 3, according to Misch classification, was found as the mean value of radiological bone density. It can be concluded that implant-supported rehabilitation in kidney-transplanted patients is possible. Adequate periodontal maintenance allows implant rehabilitation in kidney transplanted patients with long-term sufficient survival rates.

Statement of the problem: 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.

Materials and methods: A nine-part questionnaire was provided to dentists. Data collected included Clinicians' roles, implant surgeons, restorative clinicians, or both-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.

Results: One hundred twelve dentists voluntarily completed the survey.54% restored, 37% restored and replaced, and 9% solely placed implants. 29% 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. 30% never tie floss tethers to screwdrivers, and a similar percentage reported only sometimes. Throat pack protection was reported 51% of the time. 90% considered dropping components an issue, with screwdrivers most problematic.

Conclusions.: Aspiration or ingestion of implant screwdrivers and components is problematic with dentists varying with 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.

Bone augmentation is often required before the installation of dental implants. Here, we report a case for a patient who previously received bone augmentation at the upper right jaw using a xenogenic graft, followed by successful implant installation. Seven years later, the patient presented with mucosal fenestration with bone exposure at the area and gave a history of a recent diagnosis of cutaneous lichen planus. Several attempts were made to manage the situation, and finally, we resorted to connective tissue graft placement at the site. A piece of bone was sent for histologic evaluation, where the results indicated the presence of un-resorbed graft material surrounded by inflammatory cells, with no evidence of bone formation in the area. The case presents histologic evidence for the lack of new bone formation using xenograft over the evaluation period. The case also shows lichen planus, a possible cause for oral complication for patients undergoing augmentation and implant installation.

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 three months postoperatively, in which the difference in implant stability quotients 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 = 0.047. The difference between the maxilla and mandible of the implantation site (P=0.02) and the platform site Hounsfield units (P=0.019) 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 < 0.001. The difference between diameter (P=0.008) and the immediate ISQ (P < 0.001) 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.