Occlusal Adjustment Research Articles

PROSTHETIC REHABILITATION OF THE CLASS 3 MALOCCLUSION: A CASE REPORT

Loss of posterior teeth impacts a patient’s function as well as their facial esthetics. Changes in the Occlusal Vertical Dimension (OVD) may result in anterior crossbite or Class III malocclusion. This clinical report describes the prosthodontic management and stabilization of a patient with reverse anterior articulation due to loss of posterior occlusal support.The comprehensive diagnostic approach,the information gathered from the provisional phase and the consistent sequence of clinical and laboratory stages led to a definitive treatment outcome that guaranteed the success of the prostheses and the patient’s comfort and satisfaction.The clinical case described indicates that the prosthodontic management of Class III malocclusion, when carefully planned, can be a safe procedure that aims to ensure the immediate and longitudinal improvement of a patient’s function and esthetics.The treatment was based on the class III diagnosis. Therefore, the patient was rehabilitated by occlusal adjustments and conventional teeth and tissue - supported prostheses and without the need for invasive orthognathic surgery.

Efficacy of two polishing systems in reestablishing the surface smoothness of posterior monolithic lithium disilicate restorations: One-year results of a split-mouth randomized controlled clinical trial

Statement of problemSelecting the optimal polishing procedure to reestablish surface smoothness after occlusal adjustment is essential for the long-term success of glass-ceramic restorations. While in vitro studies have shown different effective polishing protocols, clinical trials are lacking. PurposeThe purpose of this split-mouth controlled clinical trial was to evaluate the effectiveness of 2 polishing systems in reestablishing the surface smoothness of posterior monolithic lithium disilicate ceramic restorations. Material and methodsNinety-six restorations that required occlusal adjustment after bonding were randomized into 2 groups: Forty-eight restorations were polished by using the Exa Cerapol polishing kit, and the other 48 restorations were polished by using the Shofu polishing kit. The restorations were replicated with epoxy resin at 3 study times—after bonding (t1), after occlusal adjustment (t2), and after polishing (t3)—for quantitative roughness analysis (Ra). Representative specimens from each group were qualitatively analyzed by using a confocal laser microscope. Clinical analyses were performed after the polishing procedure and at 30, 180, and 365 days after the polishing procedure by following the United States Public Health Service (USPHS) criteria. ANOVA and the Tukey multiple comparisons parametric tests were computed (α=.05). The Kaplan-Meier test was used to analyze the survival rate of restorations. ResultsNo statistically significant difference was found between the Exa Cerapol and Shofu groups (P=.086). A statistically significant difference was found between study times t1 and t2 and between t2 and t3 (both P<.001) in both experimental groups. No statistically significant difference was found between study times t1 and t3 (P=.181) in either experimental group. For the clinical criterion “integrity of restorations,” all the elements analyzed indicated an alfa grade at all study times. The survival rate of the restorations was 100%. ConclusionsBoth polishing kits were effective in reestablishing the surface smoothness of restorations after occlusal adjustment.

Wear of Modern Denture Teeth—A Systematic Review

The purpose of this systematic review was to identify the different methods used to measure artificial teeth wear and to determine which denture teeth (or which combination of tooth types) have better wear resistance. The focused patient, intervention, comparison, and outcome (PICO) question for this review was “which available denture teeth or combination of teeth have higher wear resistance?” The method of testing and measuring the artificial teeth wear was also evaluated as a secondary outcome. We searched OVID Medline, PubMed and SCOPUS using the following terms (MeSH words) with any synonyms and closed terms: “wear”, “denture teeth”, “denture tooth”, or “artificial tooth”, “tooth wear”, or combination of “denture tooth wear”. Database searches were limited to the English language and studies published between years 1997 and 2021. Further hand searches were carried out of studies identified from the bibliographies of relevant articles. The electronic data base search identified 293 articles of which 213 were eliminated after removing duplicates and screening the titles of the articles. A further 31 articles were eliminated upon application of the exclusion criterion and full text reading because they were either not in the English language or were review articles. Only 41 articles met the inclusion criterion; along with addition of one hand search article, a total of 42 articles were included in the review. The studies showed that rate of denture teeth wear is influenced by factors such as the material and composition of the artificial teeth, the denture tooth antagonist, the tooth being replaced, patient’s age and sex, the type of removable prosthesis and the amount of the superficial layer removed during occlusal adjustments. The testing parameters were inconsistent across all studies. In conclusion, artificial teeth of same material should be used as antagonists where possible, and the superficial outer layer of the teeth must be preserved as much as possible during occlusal adjustments to enhance wear resistance. Denture teeth should be selected taking into consideration the tooth being replaced, the age and sex of the patient, and the type of prosthesis. Incorporation of nano fillers into acrylic resin teeth does not increase wear resistance; therefore, there is no evidence to favour the use of nano-filled composite teeth over micro-filled or conventional acrylic resin teeth.

Evaluation of eccentric tooth contact on a semi-adjustable articulator by using an occlusal analysis system

Statement of problemDuplicating mandibular movement with a semi-adjustable articulator has been reported to lack accuracy. However, although previous studies have analyzed articulator movement, few have compared excursive tooth contact on the articulator with tooth contact during actual mandibular movement. PurposeThe purpose of this clinical study was to evaluate the concordance of semi-adjustable articulator contacts with intraoral contacts during eccentric movements by using a T-scan occlusal analysis system. Material and methodsForty-two participants with normal occlusion and without signs of temporomandibular disorder were analyzed for the reproducibility of eccentric tooth contact on a semi-adjustable articulator. Maxillary casts made from irreversible hydrocolloid impressions were mounted on a semi-adjustable articulator with the facebow. The condylar inclination of the articulator was set by using interocclusal records. Three recordings of right and left excursive mandibular movement and protrusive mandibular movement were made in the supine position by using the T-scan v9.1. The same procedure was then performed with the articulator. The results of complete mandibular movement from T-scan measurements were divided into 4 time points for analysis: T0, T1, T2, and T3. The concordance of intraoral and articulator occlusal contacts was evaluated at each point, and the occlusal force for each tooth was compared. Overall concordance and concordance of the working and nonworking sides were also calculated. Repeated measures analysis of variance was used to analyze differences between the concordance of intraoral and articulator contacts according to mandibular movement direction, time, and working and nonworking sides (α=.01). ResultsFor all teeth, concordance between the intraoral and articulator occlusal contacts during excursive mandibular movement was greatest at T0, decreasing at T1 and T2, and increasing at T3. No significant differences were found in the concordance among the right lateral, left lateral, and protrusive excursion (P>.01). The concordance of working side occlusal contacts during lateral excursion was significantly lower at T3 than that at T0 (P<.01). ConclusionsWhen comparing intraoral and articulator contacts during lateral eccentric mandibular movement, concordance was affected by time and working or nonworking side. Reproducibility of initial eccentric tooth contact on a semi-adjustable articulator appeared to be reliable. However, occlusal adjustment of the working side might be required after prosthesis delivery.

The prevalence of trauma from occlusion as the aggravating factors of periodontitis

Trauma from occlusion (TFO) is a local factor that can exacerbate tissue inflammation in periodontitis cases. There have been many clinical studies on TFO, but the prevalence of patients is currently unknown. The purpose of this study was to determine the majority of TFO cases as a factor that aggravates periodontitis based on the medic records at Oral and Dental Hospital, Universitas Syiah Kuala, Banda Aceh, Indonesia in 2017-2019. This study used a comprehensive sampling approach to evaluate 10,532 medical records associated with periodontal disease, including factors such as age, sex, causes, and TFO treatment. Descriptive data analysis showed that from a total of 10,532 medical records, there were 391 medical records related to periodontia. A total of 194 samples matched the inclusion criteria. There were 79 TFO patients (40.7%), 3 TFO cases (1.5%), and 112 cases (57.7%) other periodontal diseases without TFO. The prevalence of TFO as a dominant factor aggravating chronic periodontitis at the Oral and Dental Hospital, Syiah Kuala University, Banda Aceh Indonesia in 2017-2019. Patients with elderly age and female sex predominantly experience periodontitis which is aggravated by TFO.KEYWORDS: Occlusal adjustment blocking method, periodontitis, Trauma from occlusion

Evaluation of temporomandibular joint dysfunction by a mandibular tracing system: A case report

Objective: The purpose of this case report was to present a digital mandibular tracing technique that is used to evaluate a patient with temporomandibular joint dysfunction (TMD). Clinical features: A 65-year-old Caucasian female patient presented with chronic jaw pain in her temporomandibular joint (TMJ) area. The patient describes a dental history of orthodontic and prosthodontic treatment. Orally patient exhibits super erupted teeth, multiply fractured restorations, facial gingival recession, and rotated teeth. The patient also had an uneven occlusal plane and non-working side contact at maxillary first and mandibular second molars. Evaluation and outcome: A digital mandibular tracing technique, cone beam computed tomography, and full-arch optical impressions were used to evaluate the patient’s condition. The left condyle was slightly flat compared with the right one on the anterior surface. Limited protrusion and lateral movements and asymmetric border movements were detected. Apparently, an incomplete orthodontic treatment at the patient’s early age, iatrogenic mandibular anterior restorations, and hit and slight effect are considered causes of temporomandibular joint problems. The recommended treatment plan sequence for this patient is an occlusal adjustment, replacement of defective restorations, and fabrication of an occlusal guard for one of the arches. Conclusion: A digital mandibular tracing system can help the dentist to diagnose and analyze the causes of TMD patients specifically and individually. It also provides quick resolution and management for patients with TMD.

Manejo do Bruxismo associado a Disfunção Temporomandibular: relato de caso

ABSTRACT Studies have found the association between episodes of bruxism and the presence of signs and symptoms of temporomandibular disorder (TMD). The aim of the present study was to report the diagnosis and palliative therapy of bruxism associated with TMD. Patient, 23 years old, male gender, presented at dental clinic, complaining of pain in the temporomandibular joint on the left side and alteration of the form of the anterior teeth. During the anamnesis it was documented that this symptom was recurrent and reported the habit of grinding teeth. The clinical examination observed discrepancy between the centric relation and the maximum habitual intercuspation, unsatisfactory protrusive guide, presence of wear facets, clicking and mandibular deviation during mouth opening. The Research Diagnostic Criteria for Temporomandibular Disorders (RDC / TMD) questionnaire was applied to diagnose TMD. By means of specific algorithms this disorder was classified as myofascial pain, disc displacement with reduction and osteoarthritis, all affecting the left side. Thus, it was proposed the assembly of the models in semi-adjustable articulator for occlusal mapping and waxing diagnosis, then the occlusal adjustment by selective wear and material addition was executed. After this procedure, the occlusal splint was installed as a palliative therapy for bruxism. This case report suggests that the dental approach by means of occlusal adjustment and occlusal splint, in a patient diagnosed with bruxism and temporomandibular disorder, reduces the signs and symptoms that affect the components of the Stomatognathic System.

Evaluation of Temporomandibular Joint Dysfunction by a Mandibular Tracing System: A Case Report

Objective. The purpose of this case report was to present a digital mandibular tracing technique that is used to evaluate a patient with temporomandibular joint dysfunction (TMD). Clinicalfeatures.A65-year-oldCaucasianfemalepatientpresentedwithchronicjawpaininhertemporomandibularjoint(TMJ)area.Thepatientdescribesadentalhistoryoforthodonticandprosthodontictreatment.Orallypatient exhibitssupereruptedteeth,multiplyfracturedrestorations,facialgingivalrecession,androtatedteeth.Thepatient also had an uneven occlusal plane and non-working side contact at maxillary first and mandibular second molars. Evaluation and outcome. A digital mandibular tracing technique, cone beam computed tomography, and full-arch optical impressions were used to evaluate the patient’s condition. The left condyle was slightly flat compared with the right one on the anterior surface. Limited protrusion and lateral movements and asymmetric border movements were detected. Apparently, an incomplete orthodontic treatment at the patient’s early age, iatrogenic mandibular anterior restorations, and hit and slight effect are considered causes of temporomandibular joint problems. The recommended treatment plan sequence for this patient is an occlusal adjustment, replacement of defective restorations, and fabrication of an occlusal guard for one of the arches. Conclusion. A digital mandibular tracing system can help the dentist to diagnose and analyze the causes of TMD patients specifically and individually. It also provides quick resolution and management for patients with TMD.

Remontagem clínica e ajuste oclusal de próteses totais convencionais em articulador semiajustável

The polymerization process of total dentures causes dimensional changes, making it necessary to remounting these prostheses in a semi-adjustable articulator (ASA) to perform the occlusal adjustment. The objective of this study is to report a clinical case of oral rehabilitation with conventional full dentures, which was performed by the clinical remounting of the prostheses in ASA to perform the occlusal adjustment. A 72 years old male patient sought dental care at the Polyclinic of the State University of Amazonas. After anamnesis, extra and intraoral clinical examinations were indicated for conventional full dentures. After anatomical and functional impressions, working models were obtained, on which orientation plans were made. From the individualization of the upper orientation plane, registration of the facial arch and determination of intermaxillary relations, the models were assembled in ASA. After selection, assembly and aesthetic and functional testing of artificial teeth, the prostheses were polymerized, finishing and polishing. During the installation of the prostheses, there were few occlusal contacts and an anterior open bite. With the prostheses positioned on the edges, the facial arch was recorded to remounting the upper prosthesis in ASA and interocclusal registration in the central relation position for remounting of the lower prosthesis. The occlusal adjustment was performed by means of selective wear to obtain the correct centric and eccentric occlusal contacts. Clinical remounting of total prostheses in ASA is an efficient procedure for performing occlusal adjustment and obtaining bilateral balanced occlusion.

Minimally Invasive Therapy for Smile Correction using Gingivoplasty, Tooth Bleaching and Resin Composite Restorations

A multidisciplinary approach and minimally invasive therapies are essentials to obtain effective results from aesthetic dentistry. Minimally invasive dentistry requires minimal intervention for the placement and replacement of restorations. This paper reports a case of 24-year-old female, who was dissatisfied with her dark and unsatisfactory dental restorations. After the clinical examination, it was proposed to perform a gingivoplasty, tooth bleaching and replacement of the unsatisfactory restorations with resin composite. Initially, the gingivoplasty was performed, which consisted of the following steps- periodontal probing, measurement of new zeniths and marking of bleeding points, internal bevelled incision and removal of the gingival collar with periodontal curettes. After healing period, using the combined technique, in-office bleaching was done with 35% hydrogen peroxide followed by three weeks at-home bleaching with 16% carbamide peroxide. The unsatisfactory restorations were replaced with resin composite according to dental substrate. Sequentially, occlusal adjustment, finishing and polishing with sanding discs and felt discs were performed. The multidisciplinary approach in the execution of the treatment was fundamental for the aesthetic harmonisation of the smile, providing health, well-being of the patient and professional satisfaction.

Evolution of Chewing Force in Geriatric Edentulous Patients

Abstract Objective The aim of this study was to assess the evolution of chewing force in edentulous geriatric patients rehabilitated with complete dentures. Chewing function is compromised in individuals who lose all their teeth, as well as in those with complete dentures. The maintenance and recovery of the chewing function in these patients require replacement of the lost natural teeth. Materials and Methods In this study, the chewing force was evaluated by electromyographic analysis of the temporalis and masseter muscle endings in 120 patients with old and new bimaxillary complete dentures. Results Replacement of complete dentures was shown to improve stability, retention, occlusion, and support of the prosthesis. All jaw movements were evaluated using electromyography to assess the evolution of chewing force with and without occlusal adjustment, identify premature contact points, identify occlusal interference, respect the balanced occlusal scheme, and assess the increase in muscle strength. This study found that muscle strength in patients with prosthesis without occlusal adjustment was 527.1 N but was higher for prostheses with occlusal adjustment at 614.7 N, and this strength of 614.7 N was maintained after 1 month of control. Conclusion The chewing force evolved in patients with complete dentures, and an increase was observed when occlusal adjustment was performed.

Overview on Malocclusion after Maxillofacial Trauma and Its Management

Malocclusion is one of the most common and often difficult-to-manage complications associated with post-traumatic maxillofacial injury. Maxillofacial injury is considered an important health problem worldwide. Such injuries most often have significant financial consequences and result in deformity of facial aesthetics, loss of function, and increased incidence of other health problems. Many common treatment approaches are extraction of teeth, occlusal adjustments, functional therapy, or a combination of these. An appropriate treatment plan should typically involve orthodontic treatment because it can prevent multi-segment upper jaw operations and stabilize the arches by coordinating and aligning them. The most common and important form of post traumatic malocclusion is malocclusion secondary to condylar fractures. Patient may complain of an open bite with functional disturbances, facial asymmetry. There is also improper alignment of teeth, frequent biting of the inner cheeks or tongue, discomfort when chewing or biting. Management approach of secondary malocclusion after maxillofacial trauma should include prosthetic treatment, orthodontic treatment, and implant-supported rehabilitation.

The occlusal precision of milled versus printed provisional crowns

ObjectivesThe aim of this study was to compare the occlusal precision of computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) milled versus 3D printed polymethylmethacrylate (PMMA) temporary prosthetic crowns , starting from the same digital CAD design. Materials and methodsThe study sample included 34 patients presenting 34 premolars in need of prosthetic rehabilitation: a total of 68 temporary crowns were manufactured, 34 of which milled and 34 printed. Immediately after manufacturing, the milled and printed provisionals were scanned with a desktop scanner (E1, 3Shape) to obtain STL files, that were superimposed to the original CAD design in order to identify the occlusal trueness (Analysis A). A second occlusal comparison was performed by scanning both kind of provisional after being placed intraorally with Trios scanner (3 Shape); intraoral scans were obtained in order to compare STL files of provisionals before and after occlusal adjustments (Analysis B). The occlusal trueness was identified at three reference points, P1 (vestibular cusp), P2 (palatal / lingual cusp), P3 (central fossa). The statistical analysis was performed using the R 3.4.3 statistical software (The R Foundation for Statistical Computing), with a significance level of p <0.05. ResultsOverall, the printed crowns showed lower occlusal differences than the milled crowns, when compared to the CAD design file, with a statistically significant difference in P1 (difference of 0.025 ± 0.046 mm), P2 (difference of 0.027 ± 0 0.044 mm) and P3 ( difference of 0.018 ± 0.050) for Analysis A (p <0.05). In the Analysis B the direct comparison between the degree of average difference between the pre-adjustment and the post-occlusal adjustment of the milled and printed crowns shows that the printed crowns have lower occlusal mean difference values in all three points compared to the milled ones (difference of 0.146 ± 0.273 mm in P1, 0.285 ± 0.360 mm in P2 and 0.257 ± 0.277 mm in P3). ConclusionsWithin the limitation of this study, the data obtained showed a better occlusal surface dimensional accuracy of the 3D printed provisional crowns, when compared to the milled ones. Comparing the results obtained, it is possible to assume that the intraoral scans also had a contribution to occlusion, beside the manufacturing method. 3D printing can be successfully applied for manufacturing temporary PMMA crowns.

Crown Accuracy and Time Efficiency of Cement-Retained Implant-Supported Restorations in a Complete Digital Workflow: A Randomized Control Trial.

This is a clinical study to compare complete digital workflows generated using intraoral scanning and the split-file technique with a conventional workflow for cement-retained implant-supported restorations. Forty patients requiring posterior single-unit implant restorations were included. Twenty patients were randomly assigned to the complete digital workflow group, involving intraoral scanning and manufacture of cement-retained crowns using the split-file technique (test group). The remaining 20 patients were assigned to the hybrid workflow group (control group), involving conventional impressions and CAD-CAM fabricated crowns based on stone casts. Scanning of the crowns was performed before and after clinical adjustment using an intraoral scanner (TRIOS Color; 3Shape). Two 3D digital models were trimmed and superimposed to evaluate changes in dimensions using Geomagic Control 2014 software. Chair-side and laboratory times for the entire workflow were recorded. Independent-sample t tests were used for the statistical analysis. All crowns were inserted without refabrication. The average maximum occlusal adjustment of the crowns, measured as maximum deviation of occlusal area in superimposed pre and post scans, was -212.7 ± 150.5 and -330.7 ± 192.5 µm in the test and control groups, respectively (p = 0.037). The average area of occlusal adjustment, measured as area of deviation larger than 100 µm, was 8.4 ± 8.1 and 17.1 ± 12.3 mm2 in the test and control groups, respectively (p = 0.012). The mesial and distal contact adjustment amounts, maximum deviations of proximal area, were -33.0 ± 96.2 and -48.6 ± 70.5 µm in the test group, and -3.7 ± 66.7 µm and -11.4± 106.7 µm in the control group, respectively. The mean chair-side time was 20.20 ± 3.00 and 26.65 ± 4.53 minutes in the test and control groups, respectively (p < 0.001). The mean laboratory time was 43.70 ± 5.56 and 84.55 ± 5.81 minutes in the test and control groups, respectively (p < 0.001). Single-unit cement-retained crowns with complete digital workflows required fewer crown adjustments and had shorter clinical and laboratory times compared to conventional impressions and hybrid workflows. Digital impressions and the split-file technique provided customized abutments and cement-retained crowns, thus broadening the indications for digital workflows for implants.

Fully digital workflow for replicating treatment dentures: A technique for jaw relation transfer and dynamic occlusal adjustment

This technique report presents a novel method of digitally replicating a treatment denture and converting it into a definitive denture. The procedure accurately duplicates the appearance of the mucosal surface and border of the treatment dentures, mounts the jaw relation on a virtual articulator to arrange artificial teeth, and optimizes the occlusion based on recorded mandibular motion tracks. This technique uses personalized jaw relation transfer and dynamic occlusal adjustment to establish balanced occlusion, which accomplishes the digital duplication of the treatment denture with high accuracy and minimal effort.

Efficacy of tooth splinting and occlusal adjustment in patients with periodontitis exhibiting masticatory dysfunction: A systematic review.

To evaluate the efficacy of tooth splinting (TS) and occlusal adjustment (OA) compared to no TS or OA in patients with periodontitis exhibiting masticatory dysfunction. The primary outcome criterion was tooth loss (TL), and the secondary outcome parameters were change in probing pocket depth (PPD), change in clinical attachment level (CAL), tooth mobility (TM), and patient-reported outcome measures (PROMs). Literature search was performed on three electronic databases (from 01/1965 to 04/2021) and focused on clinical studies with at least 12 months follow-up. From a total of 1515 publications, 51 articles were identified for full-text reading, of which 2 retrospective case series on TS with low risk of bias and 1 randomized and 2 prospective studies on OA with unclear risk of bias were included. For TS, synthesis of data showed that in 72 patients, 26 out of 311 teeth (weighted mean incidence of TL 8.4%) and 156 out of 1541 teeth with no TS (weighted mean incidence of TL 10.1%) were lost over 2 years following non-surgical periodontal therapy. The randomized controlled clinical trial (RCT) indicated CAL gain for teeth with OA compared to no OA. For the effect of OA on TL, PPD, and TM, heterogeneous data were retrieved from the included studies. Within the limitations of this review and based on a low level of evidence, it is concluded that TS does not improve survival of mobile teeth in patients with advanced periodontitis. OA on teeth with mobility and/or premature contacts may lead to improved CAL, while the effect of OA on the remaining periodontal parameters remains unclear.

A Multi-Center Disclusion Time Reduction (DTR) Randomized Controlled Occlusal Adjustment Study Using Occlusal Force and Timing Sensors Synchronized with Muscle Physiology Sensors.

Objective—To perform a Randomized Controlled Trial (RCT) Disclusion Time Reduction (DTR) study at five Dental Colleges, using intraoral sensors and muscular electrodes. Methods and Materials—One hundred students were randomly assigned to a treatment group to receive the ICAGD coronoplasty, or a control group that received tooth polishing. All subjects answered symptom questionnaires: Beck Depression Inventory-II, Functional Restrictions, and Chronic Pain Symptom and Frequency. Subjects self-reported after ICAGD or placebo at 1 week, 1 month, 3 months, and 6 months. The Student’s t-Test analyzed the measured data. The Mann–Whitney U Test analyzed the subjective data (Alpha = 0.05). Results—The Disclusion Times, BDI-II scores, and Symptom Scales were similar between groups prior to treatment (p > 0.05). At 1 week, all three measures reduced in the treatment group, continuing to decline over 6 months (p < 0.05), but not for the controls (p > 0.05). Symptom Frequency, Functional Restrictions, and Pain Frequencies were higher in the treated group (p < 0.05), but declined after ICAGD compared to the control group (p < 0.05). Conclusions—ICAGD reduced Pain, Functional Restrictions, Symptom Frequency, and Emotional Depression within 1 week, which continued for 6 months. The tooth polishing did not initiate a placebo response.

Research on the Characteristics of Food Impaction with Tight Proximal Contacts Based on Deep Learning.

Objective Based on deep learning, the characteristics of food impaction with tight proximal contacts were studied to guide the subsequent clinical treatment of occlusal adjustment. At the same time, digital model building, software measurement, and statistical correlation analysis were used to explore the cause of tooth impaction and to provide evidence for clinical treatment. Methods Volunteers with (n = 250) and without (n = 250) tooth impaction were recruited, respectively, to conduct a questionnaire survey. Meanwhile, models were made and perfused by skilled clinical physicians for these patients, and characteristics such as adjacent line length, adjacent surface area, tongue abduction gap angle, buccal abduction gap angle, and occlusal abduction gap angle were measured. A normality test, differential analysis, correlation analysis of pathological characteristics of the impaction group, principal component analysis (PCA), and binary logistic regression analysis were performed. Results The adjacent line length, adjacent surface area, tongue abduction gap angle, buccal abduction gap angle, and occlusal abduction gap angle all met normal distribution. There were statistically significant differences in adjacent line length (p < 0.001), adjacent surface area (p < 0.001), and occlusal abduction gap angle (p < 0.001) between the two groups. After dimensionality reduction by PCA on characteristics, adjacent line length, adjacent surface area, buccal abduction gap angle, and occlusal abduction gap angle had a strong correlation with the principal components. Binary logistic regression analysis showed that adjacent line length and adjacent surface area had positive effects on impaction. The buccal abduction gap angle and occlusal abduction gap angle had a significant negative influence on impaction. Conclusion Adjacent line length, adjacent surface area, buccal abduction gap angle, and occlusal abduction gap angle are independent factors influencing food impaction.

Clinical outcomes of small-diameter implant-retained overdentures: a retrospective analysis

Aims To analyze the survival rate of small-diameter implant (SDI) retained overdenture and evaluate the implant and attachment complications, as well as prosthetic maintenances, over a follow-up period of ≤4.5 years. Materials and methods Implant placement procedures were performed by dentists at the Advanced General Dentistry Clinic, Faculty of Dentistry, Mahidol University (Thailand) for all patients treated since 2016. Panoramic and periapical radiographs were taken before and after implant placement, to assess bone height around the implant. SDIs of 3 mm diameter and 10 mm length (PW plus®, PWSE, Nakhon Pathom, Thailand) were placed. After implantation for at least 2 months, corresponding housings were incorporated into overdentures using a conventional loading protocol. Assessment of implant survival rate, implant complications, and prosthetic maintenances were conducted as part of a regular implant checkup during the recall period from 2019–2020. Subsequently, patient characteristics, implant survival rate and complications, attachment complications, and prosthetic maintenance procedures were analyzed using descriptive statistics. Results Patients included in the study (n = 27) had a mean age of 68 years, and received 119 SDIs (41 in maxilla, 78 in mandible) and 38 overdentures (15 complete overdentures, 23 removable partial overdentures). The implant survival rate was 98.3% at mean survival time of 19.4 months (range, 6–55 months). After overdenture delivery, complications related to implant, attachments, and prosthetic maintenances were recorded. One implant complication (peri-implantitis) was recorded among 119 SDIs (0.8%). Attachment (Equator®) complications included: deformation of attachment matrices (34.4%), loss of attachment screw preload (14.0%), wear of metal housing (1.6%), wear of attachment head (0.8%), and dislodgement of attachment screw (0.8%). Prosthetic maintenance procedures comprised occlusal adjustment (72.7%), tissue surface adjustment (6.8%), denture base repair (6.8%), addition of artificial teeth (2.3%), and repair of artificial teeth (2.3%). Conclusion Our findings suggest that SDI retained overdenture is a successful treatment modality with a high implant survival rate (98.3%) over a 4.5 year follow-up period. Nevertheless, SDI retained overdenture maintenance is crucial.

Full digital workflow in fixed adhesive dental prosthesis: Description of a clinical technique

Digital dentistry has gained space in several dental specialties. It is possible to achieve excellent results with the digital workflow, which combines the efficiency of the restorative material with a greater marginal adaptation. This study aimed to report a clinical case through the digital workflow, with a faster and clinically acceptable prosthetic resolution. In this clinical case report, digital workflow allowed a faster and clinically acceptable prosthetic resolution. A 45-year-old female patient reported cementation failure of the prosthetic crown on tooth 14. As it was a vital tooth, the tooth received a total crown preparation. In the same clinical session, the patient's mouth was scanned then a capture software obtained a virtual model. After, the design software planned a digital "diagnostic wax-up", so a leucitic ceramic was chosen for the rehabilitation. The ceramic block was milled and receive stain and glaze, dispensing the prosthesis laboratory. Then, the adhesive cementation was performed with a dual-polymerized resin cement. The final crown had ideal adaptation, with no need for interproximal and occlusal adjustments, with an excellent marginal fit. Within the limitations of this study, this case report showed that the digital workflow allowed a favorable result in a shorter working time, which brought back function and aesthetics, without the need for interproximal and occlusal adjustments. Keywords Prosthodontics; Cosmetic dentistry; CAD-CAM.