Axial displacement in single-tooth implant restoration: Case report

Axial displacement of an implant-supported prosthesis is frequently reported in clinical and laboratory studies. However, limited information is available about the behavior of the axial displacement of implant-supported prostheses functioning in intraoral situations. The present case report evaluated the three-dimensional displacement of posterior single implant-supported prostheses in 2 different patients. Internal connection type implants were placed, and screw and cement-retained prosthesis (SCRP) type prosthesis were delivered after an appropriate healing period. Intraoral digital scans were performed using an intraoral scanner (Cerec Omnicam, Dentsply Sirona, USA) on the day of crown delivery and one week, one month, and one year after delivery. The amount of 3-dimensional displacement of the prosthesis was evaluated by using a digital inspection software (Geomagic Control X, 3D systems, USA). The axial displacement of implant-supported prosthesis occurred in both patients. Furthermore, the amount of displacement increased over time.ope

The efficacy of convenient cleaning methods applicable for customized abutments: an in vitro study

Background: The demand for implant dentistry, which includes customized abutments, is increasing. A lot of pollutions are generated on the customized abutment surface following milling procedure. This study evaluated the surface topography and cleanliness of customized abutments after cleaning procedures, which are simply applicable in the dental clinic. Methods: Thirty computer-aided design and computer-aided manufacturing internal connection type titanium abutments were produced, milled, and randomly divided into 3 groups: steam cleaning (control group), chlorhexidine (CHX) scrubbing (test group 1), and ultrasonic cleaning with CHX solution, acetone, and ethyl alcohol (test group 2). Each group was evaluated using microscopic and microbial analysis. Results: Foreign bodies were observed on the abutment surfaces in control group and test group 1, but not in test group 2. Bacteria were observed on 40% of the agar plates following steam cleaning; most of the colonies consisted of Bacillus cereus and Staphylococcus warneri. Colony growth was absent following test group 1 and 2. Conclusion: For customized abutments, cleaning with steam is ineffective. CHX scrubbing effectively eliminates only bacteria. Ultrasonic cleaning with CHX solution, acetone, and ethyl alcohol successfully removes both foreign bodies and bacteria. Thus, the ultrasonic cleaning method is conveniently applicable in the dental clinic for eliminating contamination of the customized abutment surface.ope

Considerations and clinical appliances of various abutments in implant prostheses

In the past, restoration of implant crown, ready-made abutment produced by implant manufacturer could only be used. Using straight, angled abutment, there was a limit in adaptation multiple implants. Recently, with the development of implant and CAD/CAM technology, CAD/CAM customized abutment use has become possible which is different from the past when restoration was possible with only prefabricated abutment. Not only it makes emergence profile possible which is similar to natural teeth, but also it makes insertion path possible on CAD in multiple implant restorations. However, on anterior teeth which dental esthetics is very important, another restorations which are formed with natural colored gingiva area could be required. Titanium-based zirconia prostheses which have titanium connection and zirconia structure from 1mm above fixture platform are alternative. Therefore, the purpose of this review is to analyze the characteristics, advantages and disadvantages of the abutment which is used in multiple implant restorations, and to choose right abutment when clinical trials.ope

Submucosal zirconia implant prosthesis fabricated with CAD/CAM

They have been recently introduced many aesthetic implant prosthesis using with zirconia and CAD/CAM. However, there are many limitations in their gingival and occlusal region. In this case, submucosal zirconia implant prosthesis were fabricated with CAD/CAM system. The connection of these screw cement retained prosthesis and titanium abutment was designed to 1mm above the fixture. The clinical results were satisfactory on the aesthetics and function.ope

Mechanical Complications of Posterior Implant Restorations using CAD/CAM Titanium Customized Abutments: A Retrospective Study

Purpose: The purpose of this retrospective study was to evaluate the incidence of mechanical complications of the posterior implant-supported fixed dental prosthesis (p-ISFDP) using computeraided design and computer-aided manufacturing (CAD/CAM) titanium customized abutments and to evaluate the influencing factors on complications. Material and Methods: The incidence and consequences of mechanical complications in p-ISFDPs over a mean follow up period of 54.43 ± 6.24 months were assessed based on electronic documentations f rom 138 patients with 266 implants. All p-ISFDP utilized CAD/CAM titanium customized abutments, and were fabricated with cement-retained prostheses with occlusal screw access holes. Statistical analyses were performed to identify the risk factors of mechanical complications. Results: During the observation period (3 - 5 years), implant survival rates were 100%. Major mechanical complications were 8 abutment fractures (3.01%), 8 screw loosenings (3.01%), 2 screw fractures (0.75%), 11 chipping or fractures of veneering materials (5.58%), 23 decementations of the superstructure (11.68%). The relationship between the incidence of mechanical complications and the possible factors were not statistically significant(p > .05). Conclusion: There is no significant difference between each mechanical complication and the risk factors. P-ISFDP fabricated with CAD/CAM titanium abutments is a clinically acceptable treatment.ope

Accuracy of conventional and digital mounting of dental models: A literature review

Accurate transfer of the maxillo-mandibular relationship to an articulator (i.e., mounting) is critical in prosthetic treatment procedures. In the current study, a PubMed search was performed to review the influencing factors for the maxil lo-mandibular relationship’s accuracy. The search included digital mounting as well as conventional gypsum cast mounting. The results showed that a greater amount of displacement was introduced during positioning the maxillary and mandibular models to interocclusal records rather than the dimensional change of registration material. Most intraoral scanners resulted in an accurate repro duction of the maxillo-mandibular relationship for posterior quadrant scanning; however, the accuracy was declined as the scan area increased to a complete arch scan. The digital mounting accuracy was also influenced by the image processing algorithms and software versions, especially for complete arch scans.ope

Accurate detection for dental implant and peri-implant tissue by transfer learning of faster R-CNN: a diagnostic accuracy study

Background: The diagnosis of dental implants and the periapical tissues using periapical radiographs is crucial. Recently, artificial intelligence has shown a rapid advancement in the field of radiographic imaging. Purpose: This study attempted to detect dental implants and peri-implant tissues by using a deep learning method known as object detection on the implant image of periapical radiographs. Methods: After implant treatment, the periapical images were collected and data were processed by labeling the dental implant and peri-implant tissue together in the images. Next, 300 images of the periapical radiographs were split into 80:20 ratio (i.e. 80% of the data were used for training the model while 20% were used for testing the model). These were evaluated using an object detection model known as Faster R-CNN, which simultaneously performs classification and localization. This model was evaluated on the classification performance using metrics, including precision, recall, and F1 score. Additionally, in order to assess the localization performance, an evaluation through intersection over union (IoU) was utilized, and, Average Precision (AP) was used to assess both the classification and localization performance. Results: Considering the classification performance, precision = 0.977, recall = 0.992, and F1 score = 0.984 were derived. The indicator of localization was derived as mean IoU = 0.907. On the other hand, considering the indicators of both classification and localization performance, AP showed an object detection level of [email protected] = 0.996 and [email protected] = 0.967. Conclusion: Thus, the implementation of Faster R-CNN model for object detection on 300 periapical radiographic images including dental implants, resulted in high-quality object detection for dental implants and peri-implant tissues.ope

The effet of cooling rate on the residual stresses in the veneer ceramics of zirconia-ceramic restorations: a literature review

Nowadays, dental zirconia is widely used as a framework material for a fixed dental prosthesis as well as a single restoration. However, clinical studies have reported high incidence of veneer chipping of zirconia-ceramic restorations compared to that of metal-ceramics. Several factors were raised as the possible causes of veneer ceramic chipping, however, it is still in debate. Recently, residual stresses in the veneer ceramics after cooling process gathers attention as one possible cause of chipping and many studies reported that the rate of cooling significantly influenced the types and the amount of residual stress. The purpose of current review was to briefly describe the effect of cooling rate on the residual stress in zirconia-ceramics. It was also described that the different behavior of residual stress between zirconia-ceramics and metal-ceramics following different cooling rate.ope

Clinical Results for Maxillary Implant Overdentures with Prosthetic Systems: A Literature Review

Background: The two-implant overdenture should be considered as the first treatment option for mandibular edentulous patients. But for the maxilla, there is no widely accepted consensus yet. In this study, implant survival rate, clinical evaluations, marginal bone loss of the maxillary overdenture were investigated. Materials and Methods: “Maxillary overdenture” was the key word of this study, and with the combination of “attachment system”, “implant number”, “implant survival rate”, “clinical evaluation” and “marginal bone loss”, 21 journals were searched by “Pubmed”. Results: There were no differences in the survival rate according to the attachment systems and implant numbers. Especially, maxillary overdentures with four or more implants showed excellent results. Clinical parameters and marginal bone loss were not affected by attachment systems and implant numbers. Conclusion: For successful maxillary implant overdenture treatment, four or more implants can be considered using various attachment systems.ope

Aesthetic implant restoration with alveolar bone graft and digital method on maxillary central incisor: a case report

In case of gingival recession or bone defect in maxillary anterior implant treatment, it is not easy to obtain satisfactory clinical results. In this case, loss of the labial alveolar plate was diagnosed in the maxillary right central incisor, so after tooth extraction, soft tissue was secured and implant placement with bone graft was planned. In addition, digital guide surgery was performed for the ideal implant position, and GBR (Guided Bone Regeneration) was accompanied with the xenogeneic bone and the autologous bone collected from the mandibular ramus since alveolar bone defects were extensive. After a sufficient period of osseointegration of the implant, a temporary prosthesis was fabricated through secondary stage surgery and impression taking, and through periodic external adjustment, the shape of soft tissue was improved. In the final prosthesis fabrication, a color tone of natural teeth was induced by an gold anodized customized abutment, and an aesthetic and functional zirconia prosthesis with reproducing the shape of the temporary prosthesis through intraoral scan was delivered.ope