Occlusal contact characteristics of molar teeth with food impaction: Insights from a new digital technique.

OBJECTIVES: The objective of this study was to analyze the occlusal contact characteristics of the food-impacted teeth using a new digital technique. METHODS: A 3D occlusal analysis method was developed for studying the occlusal contact characteristics of teeth affected by food impaction. In this self-controlled study, food-impacted molars from 20 participants constituted the experimental group. The corresponding healthy teeth on the opposite side served as the control group. Variables such as occlusal force (OF), occlusal contact area (OCA), and the number and distribution of occlusal contact points (OCN) in the mesio-distal directions were measured and compared between the two groups. RESULTS: There was no statistical significant difference in the values of OF, OCA and OCN between the food-impacted molars and the healthy control molars (P > 0.05). However, paired T-tests indicated significant difference in the proportion of mesial OF, OCA, and OCN in the second molars of the experimental group (0.22, 0.28 and 0.28, respectively) and the control group (0.66, 0.63, and 0.63 respectively) (P < 0.001). CONCLUSIONS: The abnormal distribution of occlusal contacts in the second molar, primarily characterized by excessive occlusal contact in the distal direction may contribute to the occurrence of food impaction. CLINICAL SIGNIFICANCE: The present study identified variations in the distribution of occlusal contacts and occlusal component force in food-impacted teeth. These findings can assist dentists in making more targeted occlusal adjustments, or applying other treatment modalities, to effectively address food impaction.

In vivo evaluation of T-Scan in quantifying occlusal contact.

BACKGROUND: The T-scan system has been used previously to analyse occlusion, but the quantitative analysis of occlusal contact by T-Scan system has yet to be reported. OBJECTIVES: To evaluate the reliability and validity of T-Scan system for quantitatively measuring occlusal contact area and occlusal contact number. METHODS: Twenty-two individuals with normal occlusion, 11 men and 11 women, were recruited for the study. Two occlusal analysis methods, including silicone transmission analysis method (STA) and T-Scan occlusion analysis method (TSO), were used to make quantitative analysis to measure occlusal contact area (OCA) and occlusal contact number (OCN). A test-retest check was performed with an interval of 2 weeks. The values of intraclass correlation coefficients (ICC) between test-retest of each method were calculated for reliability evaluation. Pearson correlations analysis, paired t-tests, regression analysis and Bland-Altman analysis were performed for validity evaluation. RESULTS: The ICC values of STA were greater than those of TSO for OCA while for OCN, ICC values of TSO were greater than STA. The higher OCA and OCN values were found in TSO compared with STA. Pearson's correlation coefficient indicated strong relations between TSO and STA (0.730-0.812) for OCA, while good relations between then (0.569-0.583) for OCN. Paired t-test showed a significant difference between the OCA and OCN values between TSO and STA. Bland-Altman analysis showed good agreement between OCA and OCN values of TSO and STA both in men and women. Regression analysis identified a linear correlation between OCA values obtained from these two methods. CONCLUSIONS: T-Scan method showed strong reliability for measuring OCA and OCN quantitatively. Strong correlations were found between OCA values from TSO and STA method, but the validity of TSO for measuring OCN needs to be promoted. CLINICAL SIGNIFICANCE: T-Scan system demonstrates good potential in quantitative analysis of occlusion, which will expand its clinical application.

Digital Protocol to Record Occlusal Analysis in Prosthodontics: A Pilot Study.

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.

Clinical applications of the T-Scan quantitative digital occlusal analysis technology: a systematic review.

STATEMENT OF THE PROBLEM: Occlusion is associated with all disciplines of dentistry and plays a major role in the longevity of both implant- and tooth-borne restorations. Achieving occlusal harmony ensures balance is established between the dental and myofascial structures, which can be measurably established to high numerical tolerances with the T-Scan digital occlusal analysis system. PURPOSE: To describe and evaluate the known and proven applications of T-Scan digital occlusal analysis in various dental practice disciplines through a systematic review of the literature. MATERIALS AND METHODS: An electronic, English-language PubMed/MEDLINE and Cochrane Central Registry of Controlled Trials database search using the keywords "T-Scan," "TMD," "Occlusion," "Implant Protected Occlusion," and "Orthodontics" was conducted without any date restrictions. The related journal findings were hand searched to determine studies that met the eligibility criteria for inclusion in the present systematic review. RESULTS: The PubMed/MEDLINE search identified 423 articles. After removing duplicates, the titles and abstracts of the remaining 421 studies were screened. 274 ineligible articles were excluded, leaving 147 articles. Of those, 33 articles were not in English, 27 full-text articles were not available, 4 were comments and letters to editors, 1 was a review, and 2 described techniques. A total of 86 articles met the eligibility criteria for inclusion. CONCLUSION: Much scientific evidence supports the use of T-Scan, as it measures relative occlusal contact forces and the time sequence durations of occlusal contacts objectively, accurately, and repeatedly for improved treatment outcomes. The system's hardware, sensor, and software evolution from T-Scan I to today's T-Scan 10 Novus system has overcome early sensor and system drawbacks to improve the clinical performance of T-Scan in many disciplines of dental medicine.

Diagnosis, treatment planning, and comprehensive restoration of a patient with Costello syndrome: rationale and application of indirect composite resin onlays.

Patients with a complex problem set involving multiple levels of altered structure challenge the clinician to develop an individualized, appropriate treatment plan. Dentofacial deficiency, occlusal problems, and loss of tooth structure require intervention to establish stability and regain function, speech, esthetics, and masticatory muscle comfort. The comprehensive examination must quantify each problem to specify the diagnosis for realistic treatment planning. The clinical case of a patient with Costello syndrome is presented to illustrate essential concepts in diagnosis and treatment of complex cases, including (1) Global Diagnosis of anterior esthetic relationships, (2) occlusal analysis with diagnostic casts verified in centric relation, (3) comprehensive restoration previewed with a diagnostic wax-up and removable acrylic resin overlay, (4) adhesive monobody composite resin onlays that preserve tooth structure, and (5) programmed occlusion, quantified with digital occlusal analysis, to ensure stability and comfort. Costello syndrome is a neurodevelopmental syndrome causing multisystem effects, including a distinctive craniofacial phenotype, cardiovascular disease, intellectual disability, growth hormone deficiency, and dental abnormalities such as delayed dental development, bruxism, and demineralized enamel lesions. In the present case, quantification of the patient's problem set allowed precise treatment planning that resulted in predictable restoration.

Construction of a novel digital method for quantitative analysis of occlusal contact and force.

BACKGROUND: Occlusal analysis is essential in the dental clinical practice. However, the traditional occlusal analysis performed on the two-dimensional level can not directly correspond to the tooth surface with three-dimensional profile, therefore the clinical guidance value is limited. METHODS: By combining the 3D digital dental models and quantitative data from 2D occlusal contact analysis, this study constructed a novel digital occlusal analysis method. The validity and reliability of DP and SA were verified by comparing the results of occlusal analysis of 22 participants. ICC values for occlusal contact area (OCA) and occlusal contact number (OCN) were tested. RESULTS: Results confirmed the reliability of the two occlusal analysis methods with ICC values of 0.909 for SAOCA, 0.906 for DPOCA, 0.929 for SAOCN and 0.904 for DPOCN. The Bland-Altman plot, paired t-test (tOCN = 0.691, P > 0.05) and Pearson correlation analysis results (R = 0.68, p < 0.001) verified the validity between SA and DP. Then a novel digital occlusal analysis method was constructed, which not only can locate the occlusion contact and provide the quantitative analysis, but also provide a comprehensive description of the resultant force of each tooth and the component forces on the x-, y- and z-axis. CONCLUSIONS: This new occlusal analysis method can obtain quantitative analysis of occlusal contact including contact area and force information simultaneously, which will provide new impetus and greater help for clinical dental treatment and scientific research.

An overview of the digital occlusion technologies: Intraoral scanners, jaw tracking systems, and computerized occlusal analysis devices.

OBJECTIVES: Within the development of digital technologies, dental professionals aim to integrate virtual diagnostic articulated casts obtained by using intraoral scanners (IOSs), the mandibular motion of the patient recorded by using an optical jaw tracking system, and the information provided by computerized occlusal analysis systems. This article describes the various digital technologies available for obtaining the digital occlusion of a patient and outlines its challenges and limitations. OVERVIEW: The factors that influence the accuracy of the maxillomandibular relationship of diagnostic casts obtained by using IOSs are reviewed, as well as the occurrence of occlusal collisions or mesh interpenetrations. Different jaw tracking systems with varying digital technologies including ultrasonic systems, photometric devices, and artificial intelligence algorithms are reviewed. Computerized occlusal analysis systems for detecting occlusal contacts in a time sequential manner with the pressure distribution on the occlusal surfaces are reviewed. CONCLUSIONS: Digital technologies provide powerful diagnostic and design tools for prosthodontic care. However, the accuracy of these digital technologies for acquiring and analyzing the static and dynamic occlusion need to be further analyzed. CLINICAL SIGNIFICANCE: Efficiently implementing digital technologies into dental practice requires an understanding of the limitations and state of current development of the digital acquisition methods for digitizing the static and dynamic occlusion of a patient by using IOSs, digital jaw trackers, and computerized occlusal analysis devices.

Evaluation of occlusal function during orthognathic therapy : A prospective clinical trial using a digital registration method.

OBJECTIVES: Reduced occlusal function is a main characteristic of orthognathic patients. The present study aimed to investigate the extent of therapy-induced functional improvements in occlusal function using a digital diagnostic method. METHODS: This prospective clinical study included 41 orthognathic patients (24 women and 17 men, median age 27.26 ± 8.2 years) and 10 control patients (5 women and 5 men, median age 29.8 ± 13.5 years) with neutral skeletal and dental configurations. The patients were divided into classes I, II and III based on their cephalometry. Digital occlusal registrations in habitual occlusion in an upright sitting position were taken before (T1) and after (T2) therapy using the T­Scan Novus (Tekscan, South Boston, MA, USA) application. RESULTS: Class II and III patients showed a significantly less efficient occlusal pattern than the untreated controls regarding total antagonism (p < 0.001), time of occlusion (p = 0.004), occlusal asymmetry (p = 0.001), anterior antagonism (p < 0.001) and posterior antagonism (p < 0.001). After therapy, the occlusal pattern increased in both therapy groups, where class III patients became indistinguishable from the controls, and class II patients differed only in posterior antagonism (p = 0.035). CONCLUSIONS: The digital occlusal registration method proved to be a useful diagnostic tool and provided new insights into therapeutic effects in orthognathic patients. By precisely adjusting the occlusal function, masticatory performance improved significantly. CLINICAL RELEVANCE: Severe malocclusion leads to a significantly lower masticatory performance for patients, which can be improved by orthognathic therapy and captured by digital occlusal registration.

Comparison of occlusal bite force distribution in subjects with different occlusal characteristics.

OBJECTIVE: To analyze bite force distribution in subjects with different occlusal characteristics. METHODS: This prospective study included 132 candidates (50 males, 82 females) seeking orthodontic treatment, who were divided into four groups based on Angle's classification of malocclusion. T-Scan® III Version 7.0 was used to record their relative distribution of bite forces, which were compared using gender, Angle's occlusal classification, overjet, overbite, space analysis, sagittal, and transverse skeletal relations variables. RESULTS: ANOVA revealed significant differences in posterior/anterior bite force ratios between sagittal dental and skeletal relationships, overjet, and overbite groups (p < 0.05). No significant difference was found between different space analysis and transverse relationship groups (p > 0.05) or between genders (p > 0.05). CONCLUSION: Subjects with Class III, decreased overjet and decreased overbite displayed higher bite force in posterior teeth compared to other groups. This feature must be considered when evaluating patients with dental and periodontal pathologies that might be affected by excessive tooth stress, especially in subjects with oral parafunctions and bruxism.

Occlusal problems: Hearing symptoms in subjects with temporomandibular disorder.

OBJECTIVE: This study aimed to investigate the relationship between occlusal problems and hearing symptoms. METHODS: Electromyography, occlusion analysis, and hearing tests were performed on 24 patients with temporomandibular disorders and concurrent ear symptoms and 16 subjects in the control group. RESULTS: The null hypothesis of no statistically significant relationship between pure tone audiometry (PTA) values and disclusion times (DT) > 0.40 s and <0.40 s was rejected. There were statistically significant correlations between 0.25, 0.5, 1, 6, and 8 kHz airways of the right and left ear and 1 and 2 kHz bone conduction for disclusion times >0.40 s. CONCLUSION: Reducing disclusion time to <0.40 s may ameliorate ear symptoms.

Evaluation of the effect of T-Scan™ as an adjunct to stabilization splint in the treatment of temporomandibular joint disorders.

OBJECTIVE: To assess the effectiveness of the stabilization splint (SS) combined with the T-Scan™ III system in the treatment of temporomandibular joint disorder (TMD) with myofascial pain. METHODS: Forty-eight enrolled patients were randomly assigned to the SS group or T-Scan™-guided SS group. Mandibular Function Impairment Questionnaire (MFIQ), Maximum Comfortable Opening (MCO), Visual Analog Scale (VAS), and Patient Health Questionnaire-9 (PHQ-9) were used as the outcome variables. RESULTS: The occlusal contacts of patients in the SS plus T-Scan™ group showed lower Occlusal Time (OT), Disocclusion Time (DT), and Asymmetry Index of Occlusal Force (AOF) after occlusal adjustment under the guidance of the T-Scan™. Importantly, the TMD symptoms were alleviated more obviously in SS plus T-Scan™ group, with better scores for MCO and MFIQ. CONCLUSION: T-Scan™-guided occlusal adjustment of SS can obtain better OT, DT, and AOF, which furthers improvement of the therapeutic effects on TMD with myofascial pain.

Botulinum toxin type A for controlling bruxism assessed with computerized occlusal analysis: A pilot study.

Objective: To assess botulinum toxin-A (BTX-A) on mandibular movements and bite force (BF%) in bruxism.Methods: Ten bruxers were divided into 2 groups based on BF% imbalance (G1: >10%, G2: <10%). BTX-A 140U was total injected into the masseter and temporalis muscles. A T-Scan® recorded BF%, occlusion time (OT), right, left, and protrusive disclusion time (DT) before administering BTX-A, as well as 15, 45, 90, and 120 days after injection.Results: The Friedman and Wilcoxon tests found significant differences in BF% in G1 subjects at 15 days (p = 0.028 s), OT at 90 (p = 0.043 s), and 120 (p = 0.027 s) days, DTR at 90 (p = 0.046 s) and 120 (p = 0.028 s) days, DTL at 15 (p = 0.043 s) and 90 (p = 0.027 s) days, and DTP 45-90 days (p = 0.043 s).Conclusion: BTX-A induced BF% starting at 15 days post-injection and influenced lateralities later.

Comparison of two different digital occlusal analysis methods.

OBJECTIVES: The aim of this study is to compare the sensitivity of T-Scan digital occlusal analysis system and the occlusal analysis mode of the CEREC Omnicam system, which is mainly used for design/production, using the data recorded at the maximum intercuspal position. MATERIALS AND METHODS: Occlusal recordings were obtained from healthy 20 females and 20 males aged 18-25 at the maximum intercuspal position. Records were saved as.jpeg format and transferred to Adobe Photoshop CS6 program. Blue, green, and red colors (shown by the same color codes in both systems) representing light, intense, and tight contacts, respectively, were evaluated in terms of the pixel counts. For statistical comparison, the differences between the systems independent sample T test and, between the genders, one sample T test were used (α = 0.05). RESULTS: The total numbers of pixels of all colors which are evaluated with T-Scan and CEREC Omnicam in females were 31,296.6 and 15,745, respectively, and in males 39,812.3 and 17,462, respectively. In both systems, the blue contact area is the most seen. For all colors tested, T-Scan recorded more contact than those of CEREC Omnicam in both genders and statistically significant difference was found between two systems for all colors. In both systems, recorded contacts are significantly higher in men than in women. Compared with women, 27% more contact area was recorded in men with T-Scan and 11% more with CEREC Omnicam was obtained. CONCLUSIONS: While T-Scan was found sensitive even in the diagnosis of light contacts, the CEREC Omnicam was found sensitive only in the diagnosis of tight contacts. CLINICAL RELEVANCE: Although both T-Scan and CEREC Omnicam are effective in occlusal analysis, T-Scan's sensitivity was found to be higher. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04798729.

A study to evaluate psychological and occlusal parameters in bruxism.

PURPOSE: To evaluate the role of anxiety/depression and occlusal factors in bruxism using Hospital Anxiety and Depression Scale and T-Scan III respectively. METHODS: The present case control study was comprising of a group of thirty patients with bruxism (Group Br) and 30 healthy individuals as control group (Group NBr). Subjects were selected from outdoor patients visiting the dental unit with the chief complaint of wearing off/sensitivity of all the teeth due to habitual grinding. The cases were selected by using the diagnostic criteria as given by the American Academy of Sleep Medicine (AASM). Further based on similarities of age and gender, controls were selected. Tooth wear index was recorded using an index given by Ekfeldt et al. Hospital Anxiety and Depression Scale (HADS) questionnaire was administered to both the groups to evaluate anxiety and depression. Recording of occlusal parameters in both the groups was done digitally by using T-Scan III. Statistical analysis was done by using student's t-test, chi square test and Mann Whitney U test. RESULTS: Group Br had significantly greater mean tooth wear index (22.24 ± 11.5) than group NBr (5.17 ± 3.30). Group Br had significantly higher anxiety (9.03 + 1.87/7.17 + 1.82) and depression scores (8 + 1.93/6.17 + 1.23) as compared to NBr. The disclusion time of group Br was 0.652 ± 0.749 and that of group NBr was 0.247 ± 0.289 (p = 0.008). CONCLUSIONS: Subjects with higher level of anxiety, depression and increased disclusion time may have greater predilection towards suffering from bruxism (p < 0.05).

Occlusal analysis of patients with chewing side preference and symptoms of temporomandibular disorders.

OBJECTIVES: In this study, TeeTester digital occlusal analysis system was used to analyse the occlusal characteristics of chewing side preference (CSP) and non-CSP patients with TMD symptoms. METHODS: According to the questionnaire and oral examination, 80 subjects were screened and divided into four groups: 20 CSP patients with TMD symptoms, 20 CSP patients without TMD symptoms, 20 non-CSP patients with TMD symptoms, 20 non-CSP patients without TMD symptoms. TeeTester digital occlusal system was applied to measure the occlusal characteristics in all four groups, including total contect area (TCA), total occlution force (TOF), distribution of occlusal force (DOF), asymmetric index of occlusal force (AOF), occlusal time (OT), disclusion time (DT) and center of occlusal force(COF). SPSS 25.0 was used to analyze the statistical data. RESULTS: At intercuspal position, the data reveals significant differences in the maximum TOF and TCA among the four groups (P<0.05). There was significant difference in the distribution of occlusal force between the preferred side and the other side of CSP patients with or without TMD symptoms (P<0.05). Among the four groups, there were statistically significant difference in the position of the center point of occlusal force, the direction of the center point of occlusal force, and the vertical distance between the center point of occlusal force and the center line (P<0.05). The COF, maximum TOF and TCA of the preferred side of dentition were significantly positive correla⁃ted with CSP (P<0.05), according to Spearman correlation analysis. However, the maximum TOF and TCA of the both side of dentition were significantly negative correlated with TMD symptoms (P<0.05). CONCLUSIONS: 1) The occlusal characteristics of CSP patients and non-CSP patients with TMD symptoms are different. TeeTester digital occlusal analysis system provides objective parameters for the dynamic evaluation of occlusion. 2) Among all the occlusal cha⁃racteristics, maximum TOF, TCA and COF of the preferred side of dentition were positively correlated with CSP. The abnormal occlusal characteristics (maximum TOF and TCA of the whole dentition) caused by CSP are related to TMD symptoms.

[3D analysis of occlusal surfaces of teeth and their contacts. Part III. Development of a method for assessing the balance of occlusal contacts]. / 3D-analiz okklyuzionnykh poverkhnostei zubov i ikh kontaktov. Chast' III. Razrabotka metoda otsenki balansa okklyuzionnykh kontaktov.

OBJECTIVE: The aim of the study was to develop a technique for 3D analysis of the occlusal balance of teeth. MATERIAL AND METHODS: The development was carried out on the basis of the Avantis 3D software («Avantis 3D¼ LLC, Russia) using teeth scans of 50 subjects with Class I and II (Division 1) malocclusion and different degree of tooth wear. The algorithm and formulas for calculating the balance of symmetry and antero-posterior occlusal balance are presented. The essential features of the technique and the interpretation of the obtained indicators are explained on different clinical cases. Statistical analysis of the results of measuring occlusal balance of patients with different degree of teeth wear and malocclusion is presented. RESULTS: It is determined that the balance of common contacts is more important than the balance of direct contacts. CONCLUSION: Alignment of teeth without noticeable wear provides a better occlusal balance then before. The occlusal balance of worn teeth after alignment may be not good and require selective grinding or restoration of their occlusal surfaces.

Relationship between presence of abfractions and premature contacts

ABSTRACT: Abfractions (AFs) are non-carious cervical lesions considered of multifactorial etiology by several authors. Objective: Relate the presence of premature contacts and AFs. Materials & Methods: The original number of students to be analyzed were 117, 36 of whom (equal amount of women and men) were finally chosen for presenting premature contacts. 19 of them presented abfractions. A survey was conducted with questions on issues like toothbrushing habits, diet and some gastric disorders; besides the participants had to take the Hamilton Anxiety Rating Scale. Then, stone models were obtained and mounted for further occlusal analysis with WCM ® semi-adjustable articulator searching the abfractions and their coincidence with premature contacts. Fisher's exact test (p<0,05) was used to associate AF with toothbrushing habits, diet, burning symptoms and gastroesophageal reflux. Chi-square test (p<0,05) was used to associate AFs and premature contacts. Student's t-distribution was used to associate AFs with anxiety. Results: There was a significant relationship between AFs presence and premature contacts (p=0,00). There was not a significant relationship between presence of AFs and toothbrushing habits and diet. There was not a significant relationship between presence of AFs and anxiety. Conclusions: AF presence do associate with premature contacts in the same affected tooth.

Accuracy, Reliability and Clinical Implications of Static Compared to Quantifiable Occlusal Indicators.

OBJECTIVE: This literature review summarizes the properties, advantages, limitations, and clinical implications of employing static occlusal indicators compared to quantifiable digital occlusal indicators during occlusal adjustments. METHOD: An electronic database search of dental literature was carried out in PubMed/MEDLINE using the key words Occlusal Indicators, Occlusal Assessment, Static, Reliability, Dynamic, Repeatability, Validity and Clinical Accuracy. A total of 231 papers were isolated, with 129 papers considered for review. RESULTS: The included papers were grouped by Static and Dynamic Occlusal indicators. The numbers of papers in the Static Group was extremely low (only 20 papers) compared to The Dynamic group (T-Scan: 89; Dental Prescale: 28; Intraoral Scanners:17). CONCLUSION: Little evidence supports the use of static occlusal indicators due to their high degree of subjectivity required during implementation. However, much scientific evidence supports the use of T-Scan, as it measures relative occlusal forces and timing objectively, accurately, and repeatedly. For the improvement of Occlusal Practice, Subjective Interpretation using Static occlusal indicators should be replaced with digital ones for objective measurements. CLINICAL RELEVANCE: The computerized occlusal analysis system is well studied and has the capacity to provide precise time and force sequencing information to objectively evaluate occlusal contacts for improved treatment outcome.

Occlusion time, occlusal balance and lateral occlusal scheme in subjects with various dental and skeletal characteristics: A prospective clinical study.

OBJECTIVES: To analyse occlusion time, occlusal balance and lateral occlusal scheme in subjects with various dental and skeletal characteristics. METHODS: A total of 132 subjects (50 males and 82 females) seeking orthodontic treatment were included in this prospective study. Using the T-Scan III version 7.0 (Tekscan Inc, South Boston, MA, USA), the occlusion time, occlusal balance and lateral occlusal schemes were recorded and compared with gender, Angle's occlusal classification, overjet, overbite, space analysis, skeletal and transverse relations. ANOVA, t test and contingency tables analyses were performed. Statistical significance was set at P < .05. RESULTS: Occlusion time was significantly shorter in subjects with balanced occlusion (0.18 seconds, P < .001), Class I normal occlusion (0.35 seconds, P = .028) and Class I skeletal profile (0.37 seconds, P = .002). Occlusion time was significantly longer in subjects with decreased overjet (0.60 seconds, P = .003). There were significant associations between the distribution of occlusal balance and Angles' classes of occlusion, skeletal relationship, overjet, overbite and space analysis (P < .05). Lateral occlusal schemes were only associated with Angle's classes of occlusion and skeletal relationship (P < .05). CONCLUSIONS: Patients with Class I occlusion showed the least occlusion time, the most balanced occlusion and a higher frequency of canine guidance. Nonetheless, potentially balanced occlusion and group function were highly prevalent in all groups; therefore, ideal occlusion must be considered an ideal to inspire and aim for, but cannot be considered an essential requirement of every dental treatment.

Bite Force and Occlusal Patterns in the Mixed Dentition of Children with Down Syndrome.

PURPOSE: Oral function in Down Syndrome (DS) patients has been of interest to clinicians and researchers. This study aimed to evaluate the parameters of occlusal force and pattern of children with Down syndrome (DS) during mixed dentition when compared to age and gender-matched controls. MATERIALS AND METHODS: Thirty DS and 30 healthy children, aged 7 to 12 years, participated in the evaluation of the parameters of the occlusal pattern and occlusal force distribution analysis. Both groups underwent clinical examination, occlusal force and pattern measurements using a computerized occlusal analysis system (T-Scan 8 occlusal analysis, Tekscan, Inc., S. Boston, MA). Occlusion time, percentage of force distribution, force outliers, center of force target area, center of force trajectory and evaluation of closure arc were compared between the two groups using the Pearson's Chi Square test. RESULTS: Children with DS had more occlusal and vertical malocclusion compared to the control group (p < 0.001). The occlusion time for DS group (0.75 ± 0.7s) was significantly longer than the control group (0.015 ± 0.05s) (p < 0.001). The closure arc for DS group was mostly irregular (53%), while the control group showed ideal closure arc. In control group, the age had a significant influence on the occlusion time, while height, weight, and BMI had a significant influence on the mouth opening. None of these variables had such effect on children with DS. CONCLUSIONS: The results of this study showed high prevalence of orofacial dysfunction among DS population. The occlusal analysis showed that children with DS had longer occlusion time and a lack of ideal occlusion pattern compared to age matched controls.