Search

Objective Materials and Methods Results Conclusion Clinical Significance This study aimed to present three indicators that represent the proximal contact area gap change under intercuspal occlusion and to see if and how these indicators influence food impaction with tight proximal contact.Ninety volunteers were recruited for bite force measurement and intraoral scanning. Three‐dimensional surface data and buccal bite data were obtained for 60 impacted and 60 non‐impacted teeth. The scanning data were imported into the Geomagic Studio 2013 to measure three indicators, which included the gap change maximum (Δdm, μm), the buccolingual position of Δdm (P), and the gap expanded buccolingual range (S, mm). The difference between two groups of three indicators and their relationship with food impaction with tight proximal contact were analyzed by the t test, the Pearson chi‐squared test, the nonparametric Mann–Whitney U test, and the binary logistic regression analysis (a = 0.05).All indicators (Δdm, P, and S) were statistically different (p < 0.001, p = 0.002, and p < 0.001) in the impacted and non‐impacted groups. Food impaction with tight proximal contact was affected by Δdm and S (p < 0.001, p = 0.039), but not by P (p = 0.409).The excessive increase of the gap change maximum and the gap expanded buccolingual range under bite force promoted the occurrence of food impaction with tight proximal contact.The use of intraoral scanning to measure the characteristics of the proximal contact area gap change under bite force may help to deepen our understanding of the pathogenesis of food impaction with tight proximal contact. Importantly it can provide a reference basis for individualizing and quantifying occlusal adjustment treatment. [ABSTRACT FROM AUTHOR]

Background: Older adults who have undergone surgery for oral tumors are at increased risk of impaired masticatory rhythm. This study investigated the correlations between masticatory rhythm, objective masticatory performance, and subjective masticatory performance as well as factors related to masticatory rhythm. Methods: The participants were 44 adults (24 men, 20 women; age range 42~90 years old) who had undergone maxillectomy, mandibulectomy, or glossectomy and were rehabilitated with a maxillofacial prosthesis. The number of functional contact teeth pairs was confirmed by intraoral examination. Chewing rate, cycle duration, coefficient of variation (CV) for cycle duration (reflecting the stability of masticatory rhythm), and mixing ability were measured simultaneously using a mastication movement rhythm tracking device during gum chewing. Maximum occlusal force was measured using the dental prescale system. Patients' perception of chewing ability was rated using a questionnaire. Results: The Spearman's rank correlation test revealed that mixing ability, patient-rated masticatory scores, cycle duration, CV for cycle duration, and maximum occlusal force showed significant correlations with chewing rate. Multiple linear regression analysis identified mixing ability and the CV for cycle duration as significant predictors of masticatory rhythm. Conclusions: Factors associated with a faster chewing rate were higher mixing ability and masticatory scores, greater maximum occlusal force, shorter cycle duration, and smaller CV for cycle duration. Stable masticatory rhythm and mixing ability are significant predictors of chewing rate. Poor masticatory performance and unstable masticatory rhythm can result in slower chewing and thus a higher risk of inadequate dietary intake. [ABSTRACT FROM AUTHOR]

The aim of this research was to evaluate the short-term effects of initial periodontal treatment (IPT) with occlusal adjustment (OA) on lower incisors on Oral Health Impact Profile-14 (OHIP-14), clinical parameters such as probing depth (PD), bleeding on probing (BoP), gingival index (GI), clinical attachment loss (CAL), and tooth mobility using the periostest device in 30 patients with periodontitis. The patients were randomly divided into two equal groups as the test and control groups. The control group received IPT alone, while the test group received IPT+OA. The OA was applied to only four lower incisors (42, 41, 31, 32) and data were recorded at baseline (T0) and at one month after treatment (T1). There was no significant difference in the total OHIP-14 scores between the groups. The inter-group comparison revealed a significant difference in the GI of 42 teeth and in the CAL of 41 teeth (p<0.05). A significant difference was observed in the periotest value of 42 teeth between the t ime points (p<0.05). There was a significant difference in the clinical periodontal parameters in both groups at T0 and T1, while there was a significant difference in the tooth mobility of 42 teeth in the test group (p<0.05). In conclusion, IPT yields pos itive effects on clinical periodontal parameters in both groups in both time points. However, IPT combined with OA seems not to be superior to IPT only as evidenced by OHIP-14 scores, periodontal parameters, and tooth mobility in the short -term. Further long-term studies are needed to draw more reliable conclusions. [ABSTRACT FROM AUTHOR]

Objectives: Single denture rehabilitated patients have negative appraisals regarding oral function, mostly associated by stability and retention issues regarding mandibular prosthetics. Therefore, this study assessed patients' occlusal equilibration, muscle activity, and oral health-related quality of life (OHRQoL) receiving milled removable or fixed mandibular implant retained prostheses. Materials and methods: Twenty-two edentulous mandibular ridges patients were randomly distributed into two groups based on the definitive prosthesis received. Group I: Removable mandibular implant-supported overdenture, Group II: Implant retained fixed prosthesis. Occlusal equilibration was evaluated utilizing Occlusense, muscle activity via Electromyograph (EMG) at delivery, after one, and three months. The OHRQoL was evaluated by Oral Health Impact Profile questionnaire (OHIP-19) before delivery and after follow-ups. Data were collected, tabulated, and analyzed, utilizing independent t-test and One-way ANOVA followed Tukey's post-hoc test. Significance level set at P ≤ 0.05. Results: Groups I &II showed significant improvement in occlusal equilibration, muscle activity and OHRQoL. Group II demonstrated significantly higher improvement than group I in occlusal equilibration associated with muscle activity after 1 month, and in functional limitations domain in OHRQoL questionnaire after 3 months. Conclusion: Implant retained mandibular prosthesis showed improvement in occlusal equilibration, muscle activity, and OHRQoL regardless of prosthesis type employed. Fixed implant-supported prosthesis revealed better outcomes than removable mandibular implant-supported overdenture concerning occlusal equilibration, muscle activity, and OHRQoL regarding functional limitations. Clinical relevance: Implant retained mandibular prosthesis is one of best treatment options for single mandibular completely edentulous patients, as dental implants improved occlusal equilibration, muscle activity, and OHRQoL. [ABSTRACT FROM AUTHOR]

Background: Digital technologies enable the accurate replication of occlusion, which is pivotal for stability in maximum intercuspation and dynamic occlusion. CAD softwares generates standardized occlusal morphologies requiring significant adjustments. The consideration of individual mandibular movements during restoration leads to better functional integration. This pilot study evaluates the efficacy of a novel, fully digital protocol for occlusal analysis recording in prosthodontics. Methods: Patients needing single or multiple metal-free restorations were included. Teeth underwent horizontal finish line preparation, while restorations on implants were either directly screwed or used multi-unit abutments. A digital impression (Trios 3 Intraoral Scanner) captured the mouth's elements. Dynamic occlusion was recorded via Patient Specific Motion (PSM). After the placement and functionalization of temporary restorations, subsequent scans included various elements, and CAD software (Dental system) was used for the restoration design. Restorations were milled in monolithic zirconia, pressed from CAD/CAM-milled wax, and sintered. Results: An evaluation of 52 restorations in 37 patients indicated high accuracy in restorations manufactured via the fully digital workflow. Monolithic zirconia was predominantly used. Subtractive (17.3%) and additive (7.7%) occlusal adjustments were mainly chairside. Conclusion: This study underscores the efficacy of meticulous verification measures and a centric contact system in reducing the need for clinical occlusal refinements in prosthetic restorations. [ABSTRACT FROM AUTHOR]

Background: Occlusal interferences lead to changes in mandibular kinematics to compensate and improve function. However, the effects of different types of eccentric disturbance on the comminution capacity are not known. Objective: To determine the immediate effect of eccentric occlusal interferences on masticatory performance. Methods: This crossover clinical trial included 12 healthy dentate subjects aged 25.2 ± 3.3 years who were randomly submitted to seven types of occlusal interference: unilateral and bilateral laterotrusive and mediotrusive, protrusive, dummy and control (no interference). The interference forms were planned in a semi‐adjustable articulator, fabricated with composite resin and adhered to the mandibular first molars such that subjects' maximum intercuspation was maintained. Masticatory performance and the chewing rate during 20 cycles were evaluated during subjects' comminution of silicone test food under one interference condition per test day; the multiple sieve method was applied to the comminuted particles. The interference was removed upon test completion, and a 1‐week washout period was applied between tests. Results: Comminuted median particle sizes were larger under unilateral (4.94 ± 0.41 mm) and bilateral (4.81 ± 0.49 mm) laterotrusive, bilateral mediotrusive (4.65 ± 0.50 mm) and protrusive (4.83 ± 0.54 mm) interferences (p <.05) than under the control (4.01 ± 0.52 mm) and dummy (4.18 ± 0.58 mm) conditions (p <.05). Only unilateral and bilateral laterotrusive interferences narrowed the comminuted particle size dispersion (p <.05). The chewing rate did not differ among conditions (p =.1944). Conclusion: Artificial eccentric interferences had an immediate adverse effect on masticatory performance by resulting in larger comminuted particles. Clinical trial registration: Brazilian Registry of Clinical Trials (RBR‐8g5zfg8). [ABSTRACT FROM AUTHOR]

How to ensure dental stability in new positions and reduce the likelihood of relapse is a major clinical concern in the orthodontic field. Occlusal contacts between arches may affect the transmission of masticatory forces, thereby influencing the biological response of the periodontal and the oromandibular system. Occlusion factors that may influence the stability after orthodontic tooth movement (OTM) remain largely unknown. Hence, this research was conducted in order to investigate the influence of different occlusal contact patterns on tooth stability and oromandibular system including the masseter muscle and the temporomandibular joint following OTM. By modifying the occlusal surfaces, in vivo animal study models with distinct occlusal patterns corresponding to clinical circumstances were established. The relapse distance of teeth and the level of inflammatory factors in the gingival cervical fluid were analyzed. We also closely observed the histological remodeling of periodontal tissue, masseter tissue, and joint tissue after one week of relapse. Moreover, genes expression in the alveolar bone was analyzed to illustrate the potential biological mechanisms of relapse under the influence of different occlusal contact patterns following OTM. Different occlusal contact patterns after OTM in rats were established. The intercuspation contact between cusp and fossa group exhibited the lowest level of relapse movement, inflammatory factors and osteoclast activity (P < 0.05). On the other hand, groups with interferences or inadequate contacts exhibited more relapse movement, and tend to promote inflammation of periodontal tissue and activate bone resorption (P < 0.05). Adequate occlusal contacts without interference may enhance tooth stability and reduce the likelihood of relapse. After active orthodontic treatment, necessary occlusal adjustment should be made to achieve the desired intercuspation contact relationship and ensure adequate contact between the arches. The elimination of occlusal interferences is crucial to achieving optimal stability and promoting overall healthy condition of the oromandibular system. [ABSTRACT FROM AUTHOR]

Objectives: To compare the survival and complication rates of posterior screw‐retained monolithic lithium disilicate (LS2)/veneered zirconia (ZrO2) single implant crowns (SICs), as well as analyze the occlusal changes observed during a 3‐year follow‐up period. Materials and Methods: Thirty‐three patients were included and randomly divided into two groups. The test group consisted of 17 patients who received monolithic‐LS2–SIC, while the control group consisted of 16 patients who received veneered‐ZrO2‐SIC. Implant/prosthesis survival rates, technical complications, peri‐implant soft tissue conditions, and quantitative occlusal changes of SIC (obtained by the intra‐oral scanner and analyzed in reverse software Geomagic Control 2015) were assessed at 1‐ and 3‐year follow‐ups. Bone loss and Functional Implant Prosthodontic Score (FIPS) were evaluated at a 3‐year follow‐up. Results: After a 3‐year follow‐up period, one patient dropped out of the follow‐up. No implant loss was observed. One crown was fractured, resulting in prosthesis survival rates of 93.75% for the monolithic group and 100% for the veneered group. A technical complication rate of 25% (4/16) was observed in the veneered group (p =.333). No significant differences in the marginal bone loss were observed at the 3‐year follow‐up (0.00 (−0.22, 0.17) mm versus 0.00 (−0.12, 0.12) mm, p =.956). The total FIPS scores for the test group were 9.0 (9.0, 9.0), while the control group received scores of 9.0 (8.0, 10.0) (p =.953). The changes in mean occlusal clearance were 0.022 ± 0.083 mm for the test and 0.034 ± 0.077 mm for the control group (at 3 years, p =.497). The changes in occlusal contact area were 1.075 ± 2.575 mm2 for the test and 1.676 ± 2.551 mm2 for the control group (at 3 years, p =.873). Conclusion: After a 3‐year follow‐up, screw‐retained monolithic LS2 and veneered ZrO2 SIC demonstrated similar survival rates. The occlusal performance of implant prostheses needs to be closely examined during follow‐up, and appropriate occlusal adjustments need to be considered. [ABSTRACT FROM AUTHOR]

Objective: This randomized clinical trial aimed to compare the efficacy of Erich arch bars (EAB) and intermaxillary fixation (IMF) screws in reducing mandibular fractures during open reduction and internal fixation (ORIF). Methods: A total of 28 patients with mandibular fractures were randomly allocated to either the EAB group or the IMF screws group. The study evaluated various parameters including occlusal stability, complications, duration of application, oral hygiene status, quality of life, and patient characteristics. Results: The study found no significant differences in occlusal stability between the EAB and IMF screw groups. However, the application and removal times were longer for EAB compared to IMF screws. The EAB group showed a higher presence of biofilm on teeth, indicating poorer oral hygiene status compared to the IMF screws group. In terms of quality of life, patients in the EAB group reported worse results in the "handicap" domain at the 15th postoperative day. No significant differences were observed in other quality-of-life parameters. Patient characteristics were well distributed between the two groups, enhancing the reliability of the results. Conclusion: Both EAB and IMF screws demonstrated comparable occlusal stability for minimally displaced mandibular fractures. However, IMF screws offered advantages such as shorter application and removal times, better oral hygiene maintenance, and potentially improved quality of life in the "handicap" domain. Further studies with larger sample sizes are necessary to validate these findings and explore the stability of IMF methods in cases requiring postoperative malocclusion correction or prolonged IMF. [ABSTRACT FROM AUTHOR]

The integration of virtual surgical planning (VSP) for the treatment of skeletal, dental, and facial abnormalities and obstructive sleep apnea (OSA) with maxillofacial surgery has catapulted surgical planning. Although reported for treating skeletal-dental abnormalities and dental implant surgery, a paucity of knowledge existed reporting the feasibility and resultant outcome measures when VSP was employed for planning maxillary and mandibular surgery for OSA patients. The surgery-first approach is at the forefront of advancing maxillofacial surgery. Case series reporting success with the surgery-first approach for patients with skeletal-dental and sleep apnea patients have been reported. In sleep apnea patients, clinically significant reductions in apnea-hypopnea index and improvement of low oxyhemoglobin saturation have been achieved. More so, significant improvement in the posterior airway space at the occlusal and mandibular planes were achieved, while preserving aesthetic norms as measured by tooth to lip measurements. VSP is a feasible tool used for predicting surgical outcome measures in maxillomandibular advancement surgery for patients with skeletal, dental, facial, and OSA derangements. [ABSTRACT FROM AUTHOR]

Summary: Masticatory muscle activity during sleep has been considered independent of variations in the structural characteristics of the dental occlusion. However, scientific evidence contradicting an occlusal causal role is missing. The purpose of this study was to test the null hypothesis that sleep bruxism (SB) is independent of the presence of occlusal interferences. A total of 17 healthy female subjects (mean [SD] age 24.9 [4.1] years) presenting with SB, and randomly divided into two groups, were evaluated after receiving either elimination of occlusal interferences (Test group) or elimination of sharp margins without change in occlusal contacts (Control group). Audio‐video polysomnography (PSG) recordings were undertaken before and after treatment (mean [SD] duration 14.4 [3.8] months). Two subjects in each group (< 2 rhythmic masticatory muscle activity [RMMA]/h) were excluded for statistical analysis. During the total sleep time (TST), the Test group exhibited a higher reduction in frequency of episodes per hour than the Control group (p < 0.05). The reduction in duration of episodes was also higher in the Test group during the TST. The Test group presented an increase in sleep stage N3 (p < 0.05) at the final PSG when compared with the initial PSG, and a higher percentage of N3 (p < 0.05) at the final PSG when compared to the Control group. Elimination of occlusal interferences resulted in a significant reduction of masseter and temporal muscle activity during sleep in females presenting with SB. Based on these results, the null hypothesis is rejected. The hypothesis of occlusal interferences as a risk factor for SB is still patent. [ABSTRACT FROM AUTHOR]

Background: With the introduction of high-tech appliances, anchorage devices, and improved patient awareness of the risks associated with maxillofacial surgery, treating complex situations with orthodontic treatment has become more difficult in recent years. This study was conducted to demonstrate that orienting the occlusal plane, all the dental, skeletal, and soft tissue parameters, would be improved and to find which of these parameters could be correlated with the steepness of the occlusal plane. Materials and methods: This was a retrospective study including 40 cephalometric interpretations for patients who were planned for four-unit extractions (20 cephalometric radiographies before treatment and 20 after finishing the treatment). All were treated in the same orthodontic clinic with the same protocol using the McLaughlin–Bennett–Trevisi (MBT) prescription, with 22 slots and one-step retraction following four-unit extraction based on temporary anchorage devices (TADs). Results: There was no significant change in the canting of the occlusal plane, and it remained relatively stable from 6.31° to 7.55°, while all the soft tissue-related cephalometric measurements were reduced significantly, except the nasolabial angle, as the relation of the upper and lower lip to the esthetic line of Ricketts' (E-Line) was reduced by 2.91 and 2.46°, respectively; furthermore, the angle of convexity was reduced from 10.92° to 9.79°. Besides, the upper incisor display was reduced by 0.38° Conclusions: Both the Frankfort mandibular angle and upper-incisor-to-Frankfort horizontal plane were significant parametric factors associated with profile change after extraction treatment having a positive 0.01-level Pearson association with occlusal plane steepness. Therefore, using the MBT prescription with TAD-based retraction is one of the favorable methods for the management of complex cases. [ABSTRACT FROM AUTHOR]

Objectives: The objective of this study is to evaluate the longevity of two fiber post cementation strategies in a prospective, multicenter, non-inferiority, double-blind randomized controlled trial. Methods: A total of 152 teeth, with adequate endodontic treatment and loss of coronal structure and bilateral simultaneous posterior occlusal contacts, were randomly allocated to receive glass fiber posts cemented with a conventional cementation strategy (CRC group: adhesive system + resin cement) (Adper Single Bond + RelyX ARC; 3 M-ESPE) or a self-adhesive cementation strategy (SRC group: self-adhesive resin cement; RelyX U100/U200; 3 M-ESPE). The patients were recalled annually for clinical and radiographical evaluation with a 93% recall rate (142 teeth, with 74 at CR groups and 68 at SRC group). The primary outcome was survival rate, considering the fiber post debonding (loss of retention). The secondary outcome included the success rate of the prosthetic treatment with crown debonding, post fracture, and tooth loss (not related to post failure). Both outcomes were evaluated annually. The Kaplan–Meier method and Cox regression with 95% confidence interval were used for the statistical analysis. Results: For the primary outcome (failures directly related to fiber posts cementation strategy), there were 4 fiber post debondings (2 per group), 8 root fractures (3 for SRC group and 5 for CRC group), and one mixed failure (debonding combined with root fracture for CRC), with both strategies presenting similar survival rates (p = 0.331), with 88.9% for the CRC group and 90.9% for the SRC group. For the secondary outcome (failures not related to fiber post cementation strategies), there were 8 crown debondings, 3 post fractures, and 3 tooth losses, with no statistically difference between groups (p = 0.701), with 77% for SRC and 82% for CRC. Conclusion: Fiber post cementation strategies with conventional or self-adhesive resin cement presents similar tooth survival and success rates. Trial registration: NCT01461239 Clinical relevance: Both adhesive cementation strategies led to high survival and success rates and are indicated for fiber post cementation, even after a long follow-up period (up to 106 months). [ABSTRACT FROM AUTHOR]

This systematic review aimed to identify the main tools used to analyze the relationship between the postural and stomatognathic systems. The study followed the PRISMA guidelines, and data were collected from Science Direct and PubMed databases to identify articles published until December 2022. After applying inclusion and exclusion criteria, 26 articles were selected from the initial 903 articles. The selected articles were full-text studies in English or Romanian, examining the relationship between dental occlusion and posture, measuring postural parameters using various tools, implementing occlusal changes, evaluating patients with permanent dentition, or analyzing the connection between occlusion and posture in a unidirectional manner. The findings indicate that orthognathic surgery and orthodontic mouthguards can significantly enhance postural balance and athletic performance. In addition, 63% of the studies concluded that varying modifications and occlusal conditions impact posture. Notable differences exist concerning posture and Angle dental occlusion classes, and different occlusal devices used to simulate malocclusion can affect patients' postural systems in response to external stimuli. The stabilometry platform is the predominant method for measuring postural parameters; however, other researchers have employed raster stereography, photogrammetry, mobile phone apps, and the Fukuda-Unterberger test. Consequently, interventions targeting the stomatognathic system should consider potential variations in the postural system. [ABSTRACT FROM AUTHOR]

This document is a response to criticisms made by Drs Kato, Lobbezoo, and Lavigne regarding a previous article. The authors acknowledge the methodological limitations of their study, including a small sample size and potential misunderstandings in the description of the use of composites. They argue that occlusal therapy, despite being irreversible, is beneficial and eliminates a risk factor. The authors also state that the method they used has been practiced for many years and has not been discredited. [Extracted from the article]

The article discusses the efficacy of occlusal equilibration as a treatment for sleep bruxism, a condition characterized by teeth grinding during sleep. The study, which used rhythmic masticatory muscle activity (RMMA) as the main outcome measure, found that occlusal equilibration combined with composite for anterior guidance showed promise in reducing RMMA. However, the article highlights several limitations of the study, including a small sample size, a long time delay between pre- and post-treatment measurements, and the lack of objective methods to assess the presence of occlusal interferences. The authors suggest that further research is needed to validate the findings and explore individual variability in treatment response. They also emphasize the importance of evidence-based and tailored treatments for sleep bruxism. [Extracted from the article]

Objectives: The purpose of this self-controlled clinical study was to evaluate the trueness of occlusal contacts of chairside CAD/CAM crowns fabricated using different ceramic materials. Materials and methods: Ten volunteers (8 females, 2 males, average aged 20–30) were recruited in this study registered in the Clinical Trials Registry (#NCT05346744). After tooth preparation on tooth 36 or 46, an optical scan unit (CEREC Omnicam, Sirona Dental Systems, Germany) was utilized to perform the intraoral scanning. For each volunteer, 6 crowns were fabricated via the chairside CAD/CAM process (CEREC, Sirona Dental Systems, Germany) using the following materials: InCoris TZI (ZIR), Celtra Duo (CD), e.max CAD (EMA), UP.CAD (UP), Enamic (ENA) and Hyramic (HY). The microhardness of the milled surfaces was measured through a Vickers hardness Tester (HVS-50Z, Trojan, China). Together with the amount of occlusal adjustment, the occlusal contact trueness at both milling and postprocessing stages were quantitatively analyzed by using a high-precision scanner (ATOS, GOM Technologies, USA) and a reverse engineering software (Geomagic Control, 3D Systems, Rock Hill, SC). The times of chairside occlusal adjustment were also recorded. Data were analyzed by one-way analysis of variance (ANOVA) and ANOVA with randomized block design followed by Bonferroni test (p = 0.05). Results: Significant differences were found in surface microhardness of the materials tested (CD > EMA ~ UP > ENA > HY > ZIR, p < 0.05). Regarding the occlusal contact trueness at milling stage, ZIR showed the lowest (p < 0.05), while no significant difference was found among others (p > 0.05). At postprocessing stage, except for ENA, the occlusal contact trueness of ZIR was significantly lower than that of others (p < 0.05). As for occlusal adjustment amount, ZIR was lower than CD and ENA (p < 0.05). In addition, ENA, HY and ZIR required fewer times of occlusal adjustment than EMA, UP and CD. Conclusions: The type of chairside CAD/CAM ceramic materials affected the occlusal contact trueness throughout the process of manufacturing and the amount of clinical occlusal adjustment as well. Zirconia exhibited the worst occlusal contact trueness at both milling and postprocessing stages, while the amount of occlusal adjustment was the least, which recommended the least occlusal compensation. Clinical relevance: For better trueness, different negative occlusal offsets are suggested to be applied in the design process, so as to suit the material of the restoration. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the effect of a novel interocclusal recording method on the occlusal accuracy of implant‐supported fixed prostheses for partially dentate patients with distal extension. Materials and Methods: Twenty patients with two or more adjacent teeth missing in the distal extension and scheduled to receive implant‐supported fixed prostheses were enrolled. Two interocclusal recording methods were used: placing polyvinyl siloxane (PVS) on the interocclusal recording caps (test), and placing PVS on healing abutments (control). The intraoral occlusal contacts in maximal intercuspal position (MIP) were compared with those in the mounted casts to calculate sensitivity and positive predictive value (PPV). Then, patients were randomly allocated into two groups to determine which interocclusal record would be used. The implant prostheses' evaluations mainly included occlusal adjustment height, volume, and time, occlusal contact score based on articulating paper examination. Paired‐samples t‐test, Mann–Whitney U test, and least squares regression analyzed the statistic differences. Results: The test method had higher sensitivity to detect intraoral occlusal contacts than the control method (p =.002), but similar PPV (p =.10). During the prostheses' evaluations, the occlusal adjustment height in the test group was significantly lower than that in the control group [99.4 (53.2, 134.2) vs. 159.0 (82.3, 247.8) μm, p =.03], while the occlusal contact score before adjustment was higher (p =.006). The groups had similar occlusal adjustment volume and time. Conclusions: The novel interocclusal recording method for implant‐supported fixed prostheses was more accurate and could reduce the occlusal adjustment. [ABSTRACT FROM AUTHOR]

Background: To explore the digitisation of jaw movement trajectories through devices and discuss the physiological factors and device-dependent variables with their subsequent effects on the jaw movement analyses. Methods: Based on predefined eligibility criteria, the search was conducted following PRISMA-P 2015 guidelines on MEDLINE, EBSCO Host, Scopus, PubMed, and Web of Science databases in 2022 by 2 reviewers. Articles then underwent Cochrane GRADE approach and JBI critical appraisal for certainty of evidence and bias evaluation. Results: Thirty articles were included following eligibility screening. Both in vitro experiments (20%) and in vivo (80%) devices ranging from electronic axiography, electromyography, optoelectronic and ultrasonic, oral or extra-oral tracking, photogrammetry, sirognathography, digital pressure sensors, electrognathography, and computerised medical-image tracing were documented. 53.53% of the studies were rated below "moderate" certainty of evidence. Critical appraisal showed 80% case–control investigations failed to address confounding variables while 90% of the included non-randomised experimental studies failed to establish control reference. Conclusion: Mandibular and condylar growth, kinematic dysfunction of the neuromuscular system, shortened dental arches, previous orthodontic treatment, variations in habitual head posture, temporomandibular joint disorders, fricative phonetics, and to a limited extent parafunctional habits and unbalanced occlusal contact were identified confounding variables that shaped jaw movement trajectories but were not highly dependent on age, gender, or diet. Realistic variations in device accuracy were found between 50 and 330 µm across the digital systems with very low interrater reliability for motion tracing from photographs. Forensic and in vitro simulation devices could not accurately recreate variations in jaw motion and muscle contractions. [ABSTRACT FROM AUTHOR]

Background: A wide range of functional devices allow stimulating mandibular growth in class II patients, through mandibular advancement; managing to correct this type of skeletal and occlusal disharmony. Fixed repositioning appliances apply constant forces to the TMJ and may cause remodeling of the articular condyle and glenoid fossa. Computed tomography (CT) has been the gold standard for imaging the bone and hard tissues of the TMJ, but today cone beam computed tomography (HCCT) and Nuclear Magnetic Resonance (MRI) are used, because of their low and zero levels, respectively, of radiation. Objective: to measure morphological changes through TMJ imaging evaluation after correction of class II malocclusion with functional treatment with appliances in growing patients Methods: a comprehensive systematic literature search was conducted from January 2015 to May 2023 in the following bibliographic databases PubMed, EBSCO, Embase, and the Cochrane Library. Results: 10 studies were selected. The total sample size was 210 patients, and the age range was 10.3 to 14 years. The main imaging method used was HCCT with n = 9. Conclusions: The main change described is condylar remodeling, followed by morphological adaptation of the fossa. Although no significant differences have been reported in morphological changes in the TMJ between fixed versus removable functional appliances, fixed appliances cause a higher incidence of morphological changes. [ABSTRACT FROM AUTHOR]

Dentoskeletal changes caused by the long-term use of mandibular advancement devices (MADs) for obstructive sleep apnea (OSA) have rarely been investigated in Japan. We assessed the long-term dentofacial morphological changes in 15 Japanese patients with OSA who used two-piece MADs for an average of 4 years. Lateral cephalography analyses were performed initially and 4 years later (T1). The dental assessment included overjet, overbite, upper anterior facial height, lower anterior facial height (LAFH), total anterior facial height (TAFH), and anterior facial height ratio. Dental casts were digitized and analyzed using a 3D scanner. Changes in the apnea hypopnea index (AHI) and other sleep-assessment indices were assessed using polysomnography and out-of-center sleep testing. Radiography revealed lingual inclination of the maxillary central incisors, labial inclination of the mandibular central incisors, clockwise rotation of the mandible, and an increase in the TAFH and LAFH at T1. In the dental cast analysis, the diameter width and palatal depth tended to decrease and increase, respectively. There was a significant decrease in the AHI and other sleep assessment indices after using the MADs for approximately 4 years. However, these findings do not provide a strong basis and should be interpreted cautiously. Future studies should have a larger sample size and should further investigate the long-term occlusal and dental changes caused by the original MADs in Japanese patients with OSA. [ABSTRACT FROM AUTHOR]

Occlusal analysis is important to analyze any disharmony in occlusion. Atraumatic dental occlusion leads to evolution of T-scan. T-scan gives a valuable procedure for clinical assessment and perception of occlusal problems. T-scan can also be used in periodontitis patients for checking the occlusal pattern. Occlusal problems and periodontal disease relationship remains controversial. Further research is needed to determine whether occlusal adjustment is necessary for periodontal treatment. The main aim of the study was to assess the occlusal pattern using T-scan in periodontitis patients. Thirty periodontitis subjects were taken and checked for occlusion using T-scan. The subject's age group was 35–55 years. The study included 15 males and 15 females. Plaque index, gingival index, attachment loss, probing depth, centric occlusion (CO), protrusion, right lateral, and left lateral were the parameters studied. Occlusal adjustments were needed to decrease and dissipate the abnormal occlusal forces. The significance of statistical tests for various movements are as follows: CO (right and left) (P = 0.077) P > 0.05; protrusion (right and left) (P = 0.09) P > 0.05; left side lateral (right side and left side) (P = 0.01) P < 0.05; right lateral (right side and left side) (P = 0.00) P < 0.05. CO and protrusion (right, left) for males and females are not significant. Left lateral and right lateral (right, left) for males and females were significant. The T-scan manages adequate specificity and sensitivity. Hence, these act as a distinctive tool for diagnosis and better unreliable when used intraorally. The T-scan method is definitely a valuable tool for examining and evaluating the occlusal contacts during maximal intercuspation. [ABSTRACT FROM AUTHOR]

The utility of facebow might reduce the occurrence of occlusal interferences in fabrication of three unit fixed prosthesis. There is a lack of data regarding the clinical usefulness of facebow in fixed prosthesis fabrication. The purpose of this clinical trial was to study and compare the occlusal interferences in three unit fixed prosthesis fabricated with and without facebow transfer. 15 participants satisfying predefined inclusion and exclusion criteria were selected in this clinical trial. For each participant, 2 pair of three unit fixed prosthesis were fabricated. Prosthesis were fabricated one with and other without facebow transfer. The treatment involved single operator and single technician to minimize the error if any. After fabrication, the prosthesis were evaluated on the basis of the occlusal contacts and interferences of the three unit fixed prosthesis using a 40um articulating paper. The prosthesis with better occlusal contacts was cemented and the results were evaluated using chi square test. Nine out of 15 three unit fixed partial denture prosthesis fabricated using facebow transfer had reduced incidence of occlusal interferences. 6 out of 15 prosthesis fabricated without facebow transfer had reduced incidence of occlusal interferences. The results were evaluated using chi square test which was highly significant. (P>1), the three unit fixed prosthesis fabricated with facebow transfer had reduced no. of occlusal interferences. Taking into consideration of the complex and multiphase study design of the study with a finite number of participants and one specific arbitrary face-bow, the following result could be drawn as there is significant difference in three unit fixed partial denture prosthesis fabricated by the use of the arbitrary face-bow compared to a mean setting as compared to three unit fixed partial denture prosthesis fabricated without facebow transfer. The three unit fixed partial denture prosthesis fabricated with facebow transfer yields a better prosthesis and minimizes the harmful occlusal interferences as compared to the three unit fixed prosthesis fabricated without facebow transfer. Evidence based dentistry is needed to asses and abolish the unnecessary steps in clinical dentistry. Facebow is one such step which has been questioned for long by many clinicians and there is lack if clinical trials with its use in fixed prosthodontics. This study is to evaluated the importance of use of facebow transfer in fabrication of three unit fixed prosthesis. [ABSTRACT FROM AUTHOR]

Introduction: The orientation of the occlusal plane forms the basis for the arrangement of teeth conducive to satisfactory esthetics and function, making it one of the most important clinical procedures in prosthodontic rehabilitation. This study aimed to analyze and compare the vertical distance between the anterior attachment of lingual frenum (AALF) and the incisal edge of mandibular central incisors among three races in Malaysia. Materials and Methods: The sample consisted of 63 dentate subjects (21 Malays, 21 Chinese, and 21 Indians) who were chosen based on the inclusion criteria. Two models were made using irreversible hydrocolloid impressions, and an average of the value was obtained. Lingual frenum was recorded in function. Casts were fabricated with dental stone. AALF was marked and the vertical distance was measured using a caliper. Results: In Malays, the mean and standard deviation of the vertical distance were 14.2 ± 0.9 mm, with a range of 12.3–16.0 mm; in Chinese were 14.4 ± 0.9 mm, with a range of 12.0–16.9 mm; and in Indians were 15.1 ± 1.0 mm, with a range of 13.0–17.2 mm. The difference among the three races regarding the distance between AALF and the incisal edge of mandibular central incisors was statistically significant (P < 0.05). Among the three races, Malays and Indians have the greatest mean difference. Conclusion: According to the results of the current study, the distance between AALF and the incisal edge of mandibular central incisors might be a proper criterion for the initial adjustment of occlusal rims. The values obtained from three different races were significantly different from one another, hence a different range of values was used to establish occlusal height for different races. [ABSTRACT FROM AUTHOR]

Introduction: Composite resins are considered the pinnacle of esthetic restorations, but they have their own disadvantages, such as polymerization shrinkage, low fracture toughness, and the formation of microcracks, all of which eventually results in failure of the restoration. Fracture toughness is an important factor for failure. Warming the same composites to certain temperatures will show drastic improvements in the above-mentioned flaws, especially the fracture toughness. Need for the study: Therefore, the objective of this study is to evaluate and compare the fracture toughness of three different types of composite resin systems at two different pre-heating temperatures. The study aims to provide valuable information to clinicians in choosing the most appropriate restorative material for posterior composite restorations, which can ultimately improve the treatment's success rate and reduce the risk of complications such as secondary caries, postoperative sensitivity and ultimately restoration failure. Objective: In summary, this study will compare and evaluate the fracture toughness of nanohybrid, micro-hybrid, and bulk-fill composite resins pre-heated at 50 degrees Celsius and 60 degrees Celsius. Methodology: The methodology involves dividing 72 freshly extracted premolars with intact occlusal anatomy and fully developed apical foramina into three main groups based on three different composites and further dividing each group into two sub-groups based on two different pre-heating temperatures, with 12 teeth in each group. Each tooth will then be prepared with a Class-II Mesio-Occlusal-Distal (MOD) cavity and receive pre-heated composite restoration according to its assigned group and sub-group. The prepared samples will be tested for fracture toughness using a universal testing machine. [ABSTRACT FROM AUTHOR]

A virtual occlusal adjustment in orthognathic surgery has many advantages; however, the haptic information offered by plaster casts is missing when using intraoral scans. Feeling the interferences may be helpful in defining the best possible occlusion. Whether the use of a virtual occlusal adjustment instead of the conventional approach has a significant effect on the postsurgical position of the jaws is a question that remains unanswered. This study compares a virtual method to the conventional method of defining the final occlusion. Twenty-five orthognathic patients were included. Bimaxillary and single-jaw orthognathic surgery (mandible only) was simulated. The two methods were compared regarding discrepancies in the simulated postsurgical position of the mandible, measured three-dimensionally using MeshLab (MeshLab 2020.12 3D). An analysis using SPSS revealed no significant differences between the tested methods (p-values: 0.580 to 0.713). The mean absolute discrepancies ranged from 0.14 mm to 0.72 mm, laying within the scope of the clinically acceptable inaccuracies of an osteosynthesis in orthognathic surgery. The lack of haptic information in virtual planning had no relevant influence on the definition of the final occlusion and the simulated postsurgical outcome. However, in individual cases, plaster models might still be helpful in finding the adequate occlusion, especially in the sagittal dimension and in cases of patients with an anterior open bite, but this remains to be tested. [ABSTRACT FROM AUTHOR]

Objective: 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. Material: 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. Results: 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

At the beginning of the study, 30 patients were included and after the dropping out of 5 patients during the timeline of the study, finally 25 patients were used for the statistical analysis. 2 ROC curve results Discussion The null hypothesis of the study established that there were no differences between contacts obtained with conventional and digital methods. Obtaining a reliable occlusion register with appropriate occlusal contacts is considered of great importance when restoring patients in dentistry workflows [[1]]. [Extracted from the article]

Objective: 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. Material: 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. Results: 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

Objective: 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. Material: 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. Results: 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

Objectives: This study analyzes and compares dental microwear textures on occlusal and buccal surfaces from the same tooth to determine if using these surfaces in tandem can provide complementary data for dietary reconstructions. Materials and methods: Cova de la Guineu is a Late Neolithic‐Chalcolithic burial cave located in Font‐Rubí (Barcelona, Spain). The study sample consisted of 69 individuals represented by the lower left second molar. However, only 27 individuals had well‐preserved surfaces. Dental Microwear Texture Analysis was performed on both surfaces using a Sensofar® S Neox white‐light confocal profilometer following standard procedures. Toothfrax® software was used to quantify surface complexity and anisotropy. Results: The bootstrap resampling analysis shows significant differences in complexity and anisotropy between surfaces. There is no correlation between surfaces for complexity or anisotropy. The occlusal surfaces exhibit high complexities and low anisotropies, which are similar to values observed in Late Neolithic farming groups from Belgium. Discussion: The combination of occlusal and buccal microwear signatures provided important inferences regarding the studied sample. First, occlusal complexity and anisotropy values indicate an abrasive dietary regime. Second, we propose that the higher anisotropy values found on buccal surfaces, compared to those on the occlusal ones, are attributed to the specific mechanisms of microwear formation for each surface. Finally, combining both surfaces may increase the number of samples suitable for analysis. Further studies, with greater intergroup sampling, will help to understand how buccal microwear reflects or complements DMTA signatures on the occlusal surfaces. [ABSTRACT FROM AUTHOR]

Objectives: This study aims to analyze the 5-year occlusal change in posterior implant-supported single crowns and the association between the relative occlusal force (ROF) and peri-implant bone level. Materials and methods: Partially edentulous patients who had received implant-supported single crowns in the posterior region were included. Occlusal examinations with a computerized occlusion analysis system were conducted at 0.5, 3, 6, 12, 24, 36, 48, and 60 months after delivery of the implant-supported single crown. The ROFs of implant-supported single crowns, mesial adjacent teeth, and control natural teeth were recorded. Intraoral periapical radiographs were taken at each follow-up time to evaluate marginal bone level (MBL). Ordinary least square regression was used to analyze the association between ROF and MBL. Results: Thirty-seven posterior implant-supported single crowns in 33 participants (23.9 to 70.0 years) were followed up for 0.5 to 60 months [(42.4 ± 26.0) months]. The ROF of implant-supported single crowns increased from 2 weeks to 3 months (P < 0.01) and increased continuously between all two sequential time points from 6 to 36 months, with significant differences (P < 0.05). Then ROFs of implant-supported single crowns were significantly higher than those of control teeth at 48 and 60 months (P < 0.05). Regression analysis showed that ROF was significantly associated with MBL with a coefficient of 0.008 (P < 0.05). Conclusion: The ROFs of posterior implant-supported single crown have significant change during 5 years' follow-up. The association between ROF and MBL has limited clinical significance. Trial registration: Chinese Clinical Trial Registry: ChiCTR-ROC-17012240. Clinical relevance: The occlusion of implant-supported single crowns should be carefully monitored during follow-up examinations, and occlusal adjustment should be considered to prevent overloading. [ABSTRACT FROM AUTHOR]

Background: This study aimed to determine the correlation between occlusal contact area and masticatory performance using BiteEye®, a photo occlusal analysis device and the multiple sieve method. Objectives: To calculate the occlusal contact area at various levels of interocclusal thicknesses and to measure masticatory performance with peanuts as the test material. Methods: Fifty‐two adults (30 men and 22 women) were enrolled according to specific exclusion/inclusion criteria. The occlusal contact area was measured by obtaining the interocclusal record of the maximum intercuspal position (MIP) using silicone impression material. Occlusal contact area measurements were performed in the ranges of 0–149, 0–89, 0–59, 0–29 and 0–9 μm. Masticatory performance was measured by obtaining the median particle size (X50) after converting the weight of comminuted peanuts into size using the multiple sieve method. Statistical analysis was performed at 95% significance level. Results: Interocclusal thickness comparison revealed the highest correlation with X50 in the 0–149 μm range. Stronger correlations between the occlusal contact area and X50 were observed in cases of 20 strokes of mastication (r = −.451) than in cases of 10 strokes (r = −.383), in the posterior occlusal contact area (r = −.456) than in the full arch occlusal contact area (r = −.451) and the molar area (r = −.478) than in the premolar area (r = −.296). Conclusions: The larger the occlusal contact area, the higher the masticatory performance; this correlation was statistically significant. Regarding interocclusal thickness, the highest correlation between the occlusal contact area and masticatory performance was observed in the 0–149 μm range. Clinical Trial Registration Number: GWNUDH IRB 2020‐A001. [ABSTRACT FROM AUTHOR]

Objectives: This study investigates if palaeodietary information can be obtained from pulp stones through stable isotope analysis, presents a method for their extraction from tooth samples, and assesses their utility as a source of paleodietary information when coupled with the incremental dentine method. Materials and Methods: Six tooth samples (2 per individual), four of which contained pulp stones, were selected from three Early Neolithic (3720–3650 cal BC) individuals from the Whitwell Long Cairn in Derbyshire, England. After demineralization, each tooth was divided into 1 mm increments. Stable isotope analysis of collagen was conducted on each dentine increment and a portion of each pulp stone. Results: All samples met the quality control criteria for well‐preserved collagen. Excluding the pulp stones, the mean δ13C value of the teeth sampled was −21.5 ± 0.2‰ and the mean δ15N value was 9.9 ± 0.5‰, suggesting these individuals had a terrestrial‐based diet. The pulp stones produced similar δ13C values between −21.6 and −21.4‰ and δ15N values between 9.1 and 9.8‰. Discussion The results demonstrate that paleodietary information can be obtained from pulp stones through stable isotope analysis. There are, however, significant challenges in interpreting this data, particularly as to inferring the timing and duration of their formation. The pulp stone results were compared with the incremental dentine profiles for each person to further investigate when they might have formed. For two individuals, the pulp stones appear to reflect diet from a time period after childhood and adolescence. For the third individual, it could not be determined if the pulp stones reflect a contemporary or later time period than the incremental dentine series. All teeth with pulp stones have moderate to severe wear on the occlusal surface, which could have been a contributing factor to their development. [ABSTRACT FROM AUTHOR]

Objectives: The occlusal surface of many mammalian teeth has grooves that have been collectively called crenulations. The evolutionary significance of this trait is unknown, but it has been associated with a hard diet. It has not been explained, however, why crenulated molars may present an increased mechanical resistance. The objective of this study was to determine whether a crenulated surface dissipate mechanical stress more efficiently than a smooth one. Materials and methods: Using μCT scans we built 3D models of lower second molars from Homo, Pan, Gorilla, and Pongo. The crenulated models from Homo and Pongo were modified to remove crenulations. Finite element analysis was used to determine the distribution of mechanical stress in all the models when a vertical force was applied. Results: The results show that crenulated molars have a distinctive pattern of mechanical stress, namely the stress is higher in the valleys than in the crests of the crenulations. In non‐crenulated molars, mechanical stress is more homogeneously distributed. Highly crenulated molars of orangutans show the smallest values of mean stress among the compared species. Artificially removing crenulations results in more homogeneous distribution of stresses and increased mean stress values. Conclusions: Molar crenulations may increase molar resistance by canalizing mechanical stress from the tip to the base of the cusps. The overall cusp shape also influences the distribution of stress. This mechanism may be a functional hypothesis to explain the association between crenulated molars and mechanically demanding diets. [ABSTRACT FROM AUTHOR]

BACKGROUND: In the treatment of oral implant repair, different occlusal contact methods affect the internal structure of the implant and the stress distribution in the bone tissue. Whether the stress distribution is balanced or not determines the long-term life of the implant and the stability of the surrounding bone level. OBJECTIVE: To explore the effects of different occlusal contact modes on the internal stress distribution of restoration, implant, abutment, retention screw, bone tissue, binder and restoration in three kinds of occlusal relationship of maxillary central incisor implant. METHODS: The cone beam CT image data of one volunteer undergoing implant restoration of the maxillary central incisor were extracted from the database. Mimics 19.0 software was utilized to build the maxillary model, and the maxillary model was imported into Solidworks 2017 software to build the maxillary central incisor crown restoration model. Using ANSYS Workbench 17.0 software, three occlusal contact modes of end-to-end occlusion, normal occlusion, and deep overbite occlusion were loaded by simulating the distal middle edge of the crown, the midpoint of the implant diameter and the midpoint of the joint crown. The stress distribution of each structure and bone tissue in the implant restoration was analyzed under the influence of three kinds of occlusal relationship and three loading modes. RESULTS AND CONCLUSION: (1) In the end-to-end occlusion group, when the contact mode changed from the distal margin to the midpoint of the implant diameter and the midpoint of the crown, the stress of the internal structure, bone tissue and binder of the implant decreased accordingly. (2) In the normal group, when the contact mode changed from the distal margin to the midpoint of the implant diameter and the midpoint of the joint crown, the stress of the internal structure, bone tissue and binder of the implant decreased accordingly. (3) In the deep overbite group, when the contact mode changed from the distal margin to the midpoint of the implant diameter and the midpoint of the crown, the stress of the internal structure and bone tissue of the implant increased accordingly, while the stress of the binder gradually increased. (4) The results show that different occlusal contact modes and occlusal relationship affect the distribution of stress in each structure, bone tissue and binder of implant restoration. This conclusion may provide a reference basis for the adjustment of occlusal contact of implant restoration. [ABSTRACT FROM AUTHOR]

A safe method to increase the occlusal vertical dimension (OVD) in patients with mild temporomandibular symptoms (such as tenderness upon palpation) is described. After a temporomandibular joint magnetic resonance (MR), an OVD increase was sought, pursuing pure rotational movement without condyle displacement. Prior to definitive rehabilitation, an additional MR confirmed steady and healthy condyle‐disc‐fossa relationships. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Highly severe malocclusion cause dysfunctions and deformation of facial features which result in low self-esteem. Treatment method of choice is combined orthodontic and surgical treatment. Time after surgery is difficult for the patients. Large swelling and sensory disturbances result in discomfort and anxiety. Those negative feelings can be minimized by appropriate patient's mental preparation before surgery and personalized care based on patient's needs after surgery. The aim of the study is to present a model of nursing a patient undergoing surgical correction of dental and occlusal abnormalities. [ABSTRACT FROM AUTHOR]

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. The authors, hereby present a case of a 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. [ABSTRACT FROM AUTHOR]

Objective: The aim of this clinical trial was to evaluate the 2-year clinical performances of high-viscosity glass ionomer and nanohybrid resin composite restorations performed without rubber dam isolation. Materials and methods: Occlusal carious lesions on the right and left mandibular second molars of 56 patients (26 female, 30 male patients) were restored in a split-mouth design. High-viscosity glass ionomer (Hv-GIC) (Equia, GC) and nanohybrid resin composite (GrandioSO, Voco) were used as restorative materials. Clinical evaluations of the restorations were performed according to the Fédération Dentaire Internationale criteria. Data were analysed using the Friedman's analysis of variance and Mann-Whitney U tests (α=0.05). Results: After 2 years, the success rate of Hv-GIC restorations was 96% and that of resin composite restorations was 100%. Hv-GIC showed lower marginal discoloration and greater surface wear and loss of anatomic form (p<0.05). Resin composite showed significantly better surface lustre. Conclusion: The 2-year performance of resin composite was similar to that of Hv-GIC for the occlusal restorations of mandibular second molars, in spite of being performed without rubber-dam isolation. Clinical relevance: Saliva contamination can be a clinically significant problem for dental restorations. High-viscosity glass ionomers are a satisfactory alternative to resin composites with the advantage of fast application in such situations. Trial registration: Clinical Trials Registration number-date: NCT04488380-22/07/2020, retrospectively registered. [ABSTRACT FROM AUTHOR]

Objectives: To assess and compare the stability and outcomes of the two surgical approaches for patients with roll asymmetry. Materials and methods: A total of 50 adult patients were consecutively recruited for this prospective study. Patients with class III asymmetry and lip or occlusal cant who underwent bimaxillary surgery were grouped according to surgical approach: asymmetric posterior impaction on both sides (API, n = 31) and posterior impaction on one side and posterior extrusion on the other side (PIE, n = 19). Postsurgical stability and outcomes between groups were determined with cone-beam computed tomography for facial midline, lip, and occlusal cant at 1 week (T1), and at least 12-month postsurgery (T2, completion of orthodontic treatment). Results: Presurgery, the upper anterior occlusal cant and lip cant were significantly greater for the PIE group (p < 0.05). Postsurgery (T2), the mandible moved upward and rotated upward in both groups. However, the upward rotation was significantly greater in the PIE group compared with the API group. Although the two approaches resulted in significant improvements in facial symmetry, the deviation in the facial midline remained under-corrected for most API patients. Conclusions: Patient outcomes for mandibular stability and facial symmetry differed between the two surgical approaches for correction of class III asymmetry with lip or occlusal cant. Clinical relevance: The findings of this study suggest that planned over-correction is a reasonable option for the approach of asymmetric posterior impaction on both sides. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this randomized clinical trial was to compare the required time of potential clinical adjustments of posterior screw‐retained monolithic zirconia implant retained crowns based on intraoral optical scanning (IOS) or conventional impressions. Materials and methods: Patients with posterior tissue level implants (Straumann RN) replacing solitary teeth were recruited. Of all patients, impressions were taken with both an IOS (3M™ TDS) and a conventional (polyether) pick‐up impression. Randomization was performed after impression taking and patients were to receive either a crown based on the digital or the conventional impression. The time required for adjustments at placement was recorded. Additionally, restoration survival and mechanical complications with a follow‐up of one year were documented. Results: Thirty two patients with 45 implants were included: 23 restorations in the test (IOS) and 22 in the control (conventional) group. The average adjustment time was 3.35 min (SD ± 3.38, range: 0–11 min) for the digital versus 6.09 min (SD ± 4.63, range: 0–18 min) for the conventional impressions (p =.039). A proper fit (no adjustments required) was achieved 39,1% in the digital and 18,2% conventional group respectively. All 45 restorations could be placed within the two planned appointments and only two minor mechanical complications occurred during the first year of function. Conclusions: The use of IOS resulted in shorter adjustment times at try‐in than conventional impressions for solitary CAD/CAM implant restorations. Screw‐retained solitary monolithic zirconia restorations on ti‐base abutments show low complication‐ and survival rates in the short term. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the precision of aligner (Invisalign®) treatment with the current material (SmartTrack®) in achieving expansion or contraction of the maxilla and occlusal contacts as simulated in the proprietary planning software (ClinCheck®, CC). Materials and methods: Thirty patients thus treated were retrospectively evaluated. Four maxillary models were analyzed per patient: a pretreatment model, a scan-based CC model, a posttreatment clinical model, and a CC model reflecting the treatment outcome as initially simulated. Thirteen transverse parameters were measured on each model separately by two investigators. Occlusal contacts were also analyzed. Results: The measuring method was validated by both investigators arriving at similar results for the effectiveness by which the simulated treatment goals had been clinically achieved. Significant differences (p < 0.05; Wilcoxon signed-rank test) were observed for transfer precision from the casts to the planning software and between the simulated and clinical outcomes. Intense occlusal contacts in the simulations materialized less common (≈ 2%) than ideal contacts (≈ 60%) in the clinical outcomes. Conclusions: The effectiveness of achieving the simulated transverse goals was 45% and was generally not found to be better with SmartTrack® than with the previously used Ex30® material. Out of 100 simulated occlusal contacts, 40 will never materialize, and achieving around 60 will adequately ensure a clinically favorable contact pattern. Clinical relevance: With the caveat that any overcorrection will to some extent reduce the precision, it seems perfectly possible to make deliberate use of overcorrection in current aligner therapies for transverse maxillary expansion or contraction. [ABSTRACT FROM AUTHOR]

Objectives: Childhood paleodietary reconstruction via dental macrowear analysis is limited in part by available methods to measure dental macrowear. We describe a method to quantify dental macrowear progression (in both deciduous and permanent molars) using a handheld intraoral scanner and two 3D occlusal topographic measurements. We assess the agreement of our macrowear proxies with an established qualitative wear scoring system and their relationship to age. Material and methods: We scanned 92 well‐preserved dentitions of immature individuals from the medieval cemetery of St. Pölten in Lower Austria using an intraoral scanner. Two measurements were made on the resulting mesh files—the relative flat surface area in % of the occlusal surface (RFSA%) and the mesial interior slope angle. We estimated the technical error of measurement (TEM). Comparisons were made with the macrowear scoring system—tooth wear index. Results: We found that TEM for both measurements was between 1 and 3%, except the interobserver TEM of RFSA% which was above 5%. Both quantitative measurements generally agree with the established qualitative scores and correlate with age; however, RFSA% does not reliably indicate the progression of macrowear for teeth after dentine exposure occurs. Discussion The proposed 3D topographic measurements can be made reliably, and within a certain range of wear provide good quantitative proxies of the progression of dental macrowear. Such measurements constitute a promising approach for improving dental macrowear analysis in contexts such as childhood paleodietary reconstruction, which benefit from additional precision in wear rate estimation and present less dentine exposure. [ABSTRACT FROM AUTHOR]

Background: Chronic facial pain is a serious condition affecting millions of people worldwide. The reasons for chronic facial pain vary, and currently, the methods of treating chronic facial pain are expensive, invasive, and, based on current findings, ineffective. The purpose of this study is to develop and test an effective, cost-friendly method to treat patients with chronic facial pain. This study will examine the effectiveness of a novel treatment of a patient suffering from trigeminal neuralgia.Case Presentation: A 70-year-old Thai female visited the advanced general dentistry clinic at the Faculty of Dentistry, Mahidol University, Bangkok, Thailand. She was suffering from facial pain on her left side and was diagnosed by a physician as having trigeminal neuralgia. She experienced a sharp shooting pain that was triggered by facial movements such as chewing, speaking, or brushing teeth, and touching certain areas of her face. Bouts of pain lasted from a few seconds to several minutes, and episodes of several attacks lasted days, weeks, months, or longer prior to her visit to the advanced general dentistry clinic at Mahidol University. Physician designed an occlusal equilibration appliance for treating the patient by inserting the appliance in the mouth for dental occlusal equilibration (deprogram). The patient used this appliance by placing it in the mouth continuously (day and night) and removed it only when eating. After using the appliance for 2 weeks, the patient appeared to feel and look better prior to taking medication and was able to eat normally. The patient was pain free after treatment for a duration of 9 months. However, after 9 months, the pain reoccurred and manifested itself.Conclusion: This novel treatment of recurrent facial pain showed an improvement of the patient's chronic facial pain and serves as evidence to being a novel method for treating those suffering from trigeminal neuralgia. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine whether or not the analysis of maximal intercuspation, protrusive and laterotrusive movements requires an additional digital method of occlusal diagnosis using the T-Scan™ Novus™ device (TekScan). In this observational study, we retrospectively examined a number of 10 subjects which were divided into 2 groups: the 1st group involved patients with intact dental arches and the 2nd group with patients that had received implant-supported restorations. The methods of analysis involved the calibrated articulating paper of 200 and 40 micrometers, and also the T-Scan™ Novus™ device (TekScan). The following data were collected: contact points in maximum intercuspation (functional and premature contacts), the pairs of teeth performing protrusion and right/left laterotrusion, active/passive interferences and premature contacts during protrusion and right/left laterotrusion. Descriptive statistics were obtained using the MedCalc Statistical Software version 19.2.6 (MedCalc Software bv, Ostend, Belgium) and Microsoft Excel for MAC 2011. It was tested if a statistically significant difference existed between the diagnostic methods regarding the number of contact points. The T test for independent samples without the assumption of equal variances and the Mann-Whitney test was used (to which we reported the medians of the 2 subgroups and the P value adjusted for equalities) and also the magnitude of association using the Chi-square test (p value) was measured. Also it was studied the correlation between the number of premature contacts and the number of contact points, respectively, obtained by each diagnostic method, and we expressed the results through the Spearman correlation coefficient. The analysis of the maximum intercuspation, of the protrusive and the laterotrusive movements has shown comparable results using the two examination methods. There were no statistically significant differences between the two methods of analyzing dental occlusion. [ABSTRACT FROM AUTHOR]

The authors stated opinion that the T-Scan sensor thickness "could be the responsible of the false positives" is just conjecture, in that nothing in their study method analyzed how sensor thickness correlated to false positive data. These "false positives" are actually the sensor-detected I force spread i , that sensor studies have shown the T-Scan can accurately and repeatedly measure SP . sp [[1]-[5]]. Note that the T-Scan data (right pane d) is broader mesiodistally and buccolingually than are the external scanner contact representations (left pane c), directly to left of the T-Scan data set. [Extracted from the article]

Background: This study aimed to evaluate the effect of mandibular complete dentures relining using soft relining material on the distribution of various occlusal forces using T-Scan system. Fifty completely edentulous patients having their conventional complete dentures earlier fabricated and utilized were selected for this study. Patients were controlled diabetics, characterized by having their residual alveolar ridges moderately developed and lined with firm mucoperiosteum. Mandibular complete dentures were relined with soft denture liner and T-Scan device was used for occlusal force distribution measurement prior to denture relining and three months thereafter the relinning procedure. Results: Comparison between occlusal forces percentages before and after denture relining revealed that occlusal forces percentages was significantly lower after denture relining in anterior area, significantly higher after denture relining in right posterior area, where it was insignificantly higher after relining in left posterior area. Conclusions: Our findings revealed that the use of soft denture liner for mandibular complete denture relining significantly improved the occlusal load distribution. Clinical trial registration Trial registration NCT, NCT04701970. Registered 23/11/2020—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04701970 [ABSTRACT FROM AUTHOR]

Objectives: A tooth chip occurs when a hard object forcefully contacts the surface of the tooth, typically removing enamel from the occlusal edge. In this study, chipping patterns in extant primates were compared, and hard‐object‐feeding assessed alongside other factors (e.g., grit mastication and dental properties), to elucidate dietary and behavioral inferences in archeological and paleontological samples. Materials and methods: Thirteen species of extant primates were studied, including eight species within the Cercopithecidae, two within the Ceboidea, and three within the Hominoidea. Four additional species were also incorporated from the literature for some of the analyses. The severity (Grade 1–3), position (buccal, lingual, mesial, and distal) and number of tooth fractures were recorded for each specimen. Results: Species considered hard‐object‐feeding specialists presented higher rates of chipping, with sakis, mandrills, sooty mangabeys and Raffles' banded langurs having high chipping rates (28.3%, 36.7%, 48.4%, and 34.7% of teeth, respectively). Species that seasonally eat harder foods had intermediate chipping frequencies (e.g., brown woolly monkeys: 18.5%), and those that less commonly consume hard food items had the lowest chipping frequencies (e.g., Kloss gibbon: 7.3%; chimpanzees: 4.4%). Discussion: The results suggest hard food mastication influences differences in chipping prevalence among the species studied. Although Homo fossil samples show high rates of chipping comparable to hard‐object‐feeding extant primates, they display a different pattern of chipping, supporting the hypothesis that these fractures are mostly non‐food related (e.g., grit mastication in Homo naledi; non‐masticatory tooth use in Neanderthals). [ABSTRACT FROM AUTHOR]