Distribution Of Occlusal Contacts Research Articles

The Effect of Denture Adhesives on Denture Quality and Occlusal Force.

Complete dentures (CDs) have been associated with substantial problems regarding edentulous patient's function. Denture adhesives seem to be useful adjuncts to improving retention and stability. A clinical study was undertaken to investigate the effect of a denture adhesive (DA) on function in complete denture wearers along with the quality of their CDs. Thirty complete denture wearers participated in the study. The first phase of the experimental procedure comprised 3 groups of measurements performed at 3 distinct time points: the initial measurement (T1), a 2nd measurement after 15 days of DA daily application (T2), and a 3rd measurement following a 15-day washout period (T3). The second phase consisted of the follow-up measurements. The measurements included: recording of relative occlusal force (ROF), distribution of occlusal contacts (DOC) and center of force (COF) using the T-Scan 9.1 device and functional assessment of dentures using the FAD index. The DA use induced a statistically significant increase in ROF (p-value=0.003) and decrease in COF (p-value⟨0.001) and DOC (p-value=0.001). The overall FAD score significantly improved (p-value⟨0.001). The use of the DA improved the occlusal force, the distribution of occlusal contacts as well as the qualitative characteristics of CDs.

Occlusal contact and clearance of posterior implant-supported single crowns designed by two different methods: a self-controlled study

BackgroundPrecise occlusal design of implant-supported fixed prostheses is difficult to achieve by the conventional wax-up method, often requiring chairside adjustments. The computer-aided design (CAD) method is promising. This study aims to compare the occlusal contacts and clearance of posterior implant-supported single crowns designed by the CAD and conventional methods.MethodsSample size calculation indicated fourteen samples per group. Two sets of type-IV plaster casts with a single implant analog inserted in the posterior teeth region were mounted as master casts in a mechanical articulator in maximal intercuspal position (MIP). Seven working cast sets were obtained from each master cast by a closed tray technique, and mounted in MIP. Two implant-supported single crowns were designed with an occlusal clearance to achieve light occlusal contact in each working cast set by CAD and conventional method, separately. For the CAD group, the crown was designed in digital models obtained by scanning the working casts. For the conventional group, wax-up of the crown was prepared on the working casts and scanned to generate a STL file. In the working and master casts, mean and minimum occlusal clearances in the designed occlusal contact area of the both finished prostheses were calculated using the occlusal clearance (OC) and occlusal record (OR) method. The prostheses’ occlusion was evaluated in master casts.ResultsFor the evaluation in the working casts, both design methods had similar mean occlusal clearances by the OC method (195.4 ± 43.8 vs. 179.8 ± 41.8 μm; P = 0.300), while CAD group resulted in a significantly larger minimum occlusal clearance in the designed occlusal contact area (139.5 ± 52.3 vs. 99.8 ± 43.8 μm; P = 0.043). Both design methods had similar mean and minimum occlusal clearances by the OR method (P > 0.05). For the evaluation in the master casts, both design techniques had similar mean and minimum occlusal clearances, number and distribution of occlusal contacts, and lateral interference ratios (P > 0.05).ConclusionOcclusal contact and clearance of posterior implant-supported single crowns designed by the CAD method can be at least as good as those designed by the conventional wax-up method.

A new occlusal splint design for protection of anterior aesthetic rehabilitation in patients with sleep bruxism: technical note

This dental technique note describes the manufacture of a new design of occlusal splint for protection of shear forces in anterior aesthetic restorations in patients with sleep bruxism, using the computer-aided design and computer-aided manufacturing (CAD/CAM) technique. Maxillary and mandibular arches were scanned and a Jig with polyvinyl siloxane material was made to maxillomandibular relationship record. For interocclusal device planning, the anterior limits must not cover the buccal surfaces of the anterior teeth, extending only on the incisal of these dental elements. The device is then virtually designed, and the CAD file of splint is sent to CAM milling process. The occlusal splint was tested for stability, insertion and removal, the distribution of occlusal contacts and care instructions were given to the patient. This device design avoids contact between splint and anterior aesthetic restorations during occlusal forces decreasing potential of failure, which increases the success rate of these previous aesthetic rehabilitations.

Restoration of normal occlusal relations in the complex treatment of patients with generalized periodontitis and bounded edentulous spaces

The aim of the work is to restore occlusal relations during the orthopedic stages of complex treatment in patients with chronic course of generalized periodontitis (GP) of the І and ІІ degree and bounded edentulous spaces using the “T-Scan” system to achieve stable disease. Materials and methods. A total of 55 patients aged from 20 to 44 years old were examined, including 20 persons with oral health and occlusal equilibration and 35 patients with GP in its chronic phase of the I and II degree presenting with Kennedy classes III and IV partially edentulous situation (1–3). After evaluation of the dental occlusion relationships, all patients were performed a complex treatment of GP by selective grinding or occlusal surface adjustment with a composite material under the control of the apparatus “T-Scan III”, achieving the most correct distribution of occlusal contacts. At the same time, the local instrumental and medical treatment using antimicrobial and anti-inflammatory drugs and medicines with systemic effect orally to correct metabolic disorders. This was followed by the orthopedic treatment, restoring the dentition defects with fixed metal-ceramic structures under the control of the “T-Scan III” system. The results of therapy were evaluated immediately, after 6 and 12 months. Results. We have confirmed that the normal masticating pressure between the left and right parts of the dentofacial system is distributed evenly. However, we have found out, that there are not always ideal occlusion relationships, and the variation range is (48.7 to 51.3) ± 0.24 % in healthy persons. At the stages of orthopedic treatment, and especially fitting denture with the help of the “T-Scan III” system, we have reached the norm determined by us, striving for perfection. The state of periodontium and occlusion achieved after the complex treatment, remained for more than 12 months, that was confirmed by clinico-radiological data. Conclusions. Restoration of normal occlusal relations under the control of the “T-Scan III” system contributed to rapid GP remission during the orthopedic stages of complex treatment in patients with GP and bounded edentulous spaces after initial and medicamentous periodontal therapy and provided prevention of various complications and long-term stabilization of the pathological process in the periodontium.

Risk factor model of mechanical complications in implant-supported fixed complete dentures: A prospective cohort study.

This prospective cohort study estimated the effect of technical and clinical factors on mechanical complications in implant-supported fixed complete dentures (IFCDs). The patient's perception of the impact of oral rehabilitation on quality of life was assessed. A non-probabilistic sample consisted of 88 consecutive patients treated with 94 screw-retained, metal-acrylic IFCDs. Data collection included sociodemographic variables, presence and intensity of bruxism, maximal occlusal force, opposing arch, design of the metallic framework, distribution of occlusal contacts, and quality of life (OHIP-14). IFCD-level data were analyzed using Kaplan-Meier survival analysis and Cox regression model. Quality of life data were analyzed by paired Student t test. During a mean follow-up of 35.1±18.3months, 16/94 IFCDs (17%) had repairable mechanical complications because of loosening/fracture of artificial teeth (n=15) and screw loosening (n=1). Framework design (retention pins <4mm) was a significant risk factor for complications (HR=11.038; p=0.027) when adjusted for sex. Mechanical complications were not associated with sex, body mass index, thickness of the acrylic resin veneering, type of opposing arch, distribution of occlusal contacts and force, protrusion interference, presence/intensity of bruxism or maximal occlusal force. OHIP-14 total scores decreased after IFCD treatment for both patients with or without complications. Within the limitations of this study, the results suggest that clinical success is associated to framework design with retention pins equal or longer than 4mm. Quality of life improved with IFCD treatment, even in patients with mechanical complications.

Temporomandibular joint dysfunction in Parkinson's Disease: an integrative literature review

ABSTRACT Temporomandibular joint dysfunction is a set of disorders involving the masticatory muscles, temporomandibular joint and associated structures. It is known that the progression of motor symptoms in Parkinson's disease is an indication that these people are more prone to the development of this dysfunction. Thus, this study aims to investigate the signs and symptoms of temporomandibular dysfunction in people with Parkinson's disease. The search was performed in the databases: MEDLINE/ PubMed, LILACs, CINAHL, SCOPUS, Web of Science and PEDro, without timing or language restriction. Specific descriptors were used for each database and keywords, evaluated by the instruments: Critical Appraisal Skill Program and Agency for Health care and Research and Quality. A total of 4,209 articles were found but only 5 were included. After critical analysis of the methodology of the articles, one did not reach the minimum score required by the evaluation instruments, thus, it was excluded. The selected articles addressed, as signs and symptoms of temporomandibular joint dysfunction, the following: myofascial pain, bruxism, limitation of mouth opening, dislocation of the articular disc and asymmetry in the distribution of occlusal contacts. Further studies are needed in order to determine the relationship between cause and effect of the analyzed variables, so as to contribute to more specific and effective therapeutic interventions.

Computerized analysis of the distribution of occlusal contacts in individuals with Parkinson's disease and temporomandibular disorder

Objectives:The aims of the present study were to determine the prevalence of temporomandibular disorder (TMD) in a sample of patients with Parkinson's disease (PD) and to analyze the distribution of occlusal contacts.Method: The sample was composed of patients with PD aged 50–75 years. Temporomandibular disorder was evaluated using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The distribution of occlusal contacts was determined using the portable T-Scan III® occlusal analysis system during maximum voluntary clenching. Fisher's exact test was used to test the association between TMD and occlusal contact symmetry.Results: Forty-two individuals with PD were analyzed. The prevalence of TMD was 23.8%. No statistically significant association was found between TMD and occlusal contact symmetry. Moreover, no significant difference in the distribution of occlusal contacts was found between the groups with and without TMD.Discussion: The present data suggest no association between TMD and occlusal contact asymmetry in individuals with PD.Conclusion: The results of this study identified a prevalence of 23.8% of TMD signs in subjects with PD and a high frequency of occlusal asymmetry in this sample.

T Scan – An aid in achieving stable occlusion during finishing stages of orthodontic treatment

Superficial clinical examination of occlusion and just assessing the morphologic relationship of teeth at the finishing stages of orthodontic treatment may be insufficient. A case with a clinically satisfying occlusion may be functionally unbalanced. Evaluating occlusion both statically and functionally for uniform distribution of occlusal load is essential for optimum results and therefore, it is imperative to evaluate the occlusal contacts in the vertical plane. The aim of the study was to quantitatively assess the occlusion at the pre finishing stage of orthodontic treatment using T Scan in order to identify the various occlusal variabilities and compare it to the occlusion achieved after 1 month of completion of orthodontic treatment. Quantitative occlusal analysis using T Scan was performed on 16 adult patients at the start of finishing stage (T1) followed by a detailed finishing and settling phase of 2 months. Another scan was taken 1 month after debonding (T2). Using Wilcoxon matched pair test, statistically significant changes were seen in mandibular position and occlusal contacts at T2 as compared to T1. Relatively equal distribution of forces on both sides of the arch was also achieved after a detailed finishing and settling phase. Evaluation of the number and distribution of occlusal contacts at the end of active orthodontic treatment has not been a routine procedure in orthodontic clinics. 2 months of extensive finishing and detailing phase resulted in marked improvement in all three parameters and favorable changes in occlusion. Hence, evaluation of occlusion using T Scan is an innovative and objective method, emphasizing that proper finishing is mandatory for obtaining functionally stable occlusion.

Computerized analysis of the distribution of occlusal contacts in individuals with Parkinson's disease and temporomandibular disorder

Computerized analysis of the distribution of occlusal contacts in individuals with Parkinson's disease and temporomandibular disorder

Effect of Low-Level Laser Therapy on Adolescents With Temporomandibular Disorder: A Blind Randomized Controlled Pilot Study

The aim of this pilot study was to evaluate the effect of low-level laser therapy on pain, mandibular movements, and occlusal contacts in adolescents and young adults with temporomandibular disorder. Individuals aged 14 to 23 years were evaluated. The Research Diagnostic Criteria for Temporomandibular Disorders were used for the diagnosis of temporomandibular disorders. Pain was assessed with a visual analog scale. Occlusal contacts were recorded using the T-Scan III program (Tekscan, Boston, MA). The participants were randomly allocated to 2 groups: active or placebo laser treatment. The laser parameters were as follows: wavelength of 780 nm, energy density of 33.5 J/cm(2), power of 50 mW, power density of 1.67 W/cm(2), and 20-second exposure time. The Kolmogorov-Smirnov test was used to determine the normality of the data distribution. The paired t test was used for the comparisons of the pretreatment and post-treatment results. The SPSS program for Windows (version 15.0; SPSS, Chicago, IL) was used for all analyses, with the level of significance set at 5% (P < .05). No statistically significant differences between groups were found for the right and left anterior temporal muscles (P= .3801 and P= .5595, respectively), superior masseter muscles (P= .087 and P=.1969, respectively), medial masseter muscles (P= .2241 and P= .076, respectively), or inferior masseter muscles (P= .5589 and P= .3268, respectively) after treatment. No statistically significant differences were found regarding pain, mandibular range of motion,or the distribution of occlusal contacts after treatment with low-level laser therapy. These preliminary results need to be verified in a larger sample of patients to confirm the lack of response to low-level laser therapy.

The effect of mastication on occlusal parameters in healthy volunteers

To assess possible associations between occlusal parameters and comminution of solid food during chewing in a group of completely dentate subjects. Twenty-five completely dentate volunteers (28 teeth, 14 functional dental units) aged 24-50 yrs, without any complaints of the stomatognathic system participated in this study. An Optosil test was used to estimate masticatory efficiency for 20 and 80 cycles of chewing. An occlusal analysis, using the T-Scan II System, was performed to assess the following occlusal parameters: the distribution of occlusal contacts, the time of occlusion, the chewing platform area before chewing and after 20 and 80 cycles of chewing. The parameters, that were taken into account: i. X50 for 20 and 80 cycles of chewing, ii. the occlusion time, iii. the occlusal contact area. The occlusion time decreased after 20 and 80 chewing cycles (mean TO0=0.28+/-0.07 vs TO20=0.21+/-0.05 s vs TO80=0.18+/-0.05 s, respectively). The mean value of the chewing platform area was 125.12+/-46.5 mm2. Prolongation of chewing produces, shortening of the occlusion time while the chewing platform area remains at the same level independent of the number of chewing cycles.

Biological and biomechanical perspectives of normal dental occlusion

From a biological or morphological perspective, it has been accepted that normal dental occlusion requires an even and simultaneous contact of all possible teeth. On the other hand, from a biomechanical perspective, normal dental occlusion also requires adequately distributed occlusal loads on the dental arch and axial loading of occlusal force on each tooth. However, the scientific basis for this theory is fairly new, since the actual scheme of normal occlusion was recently put forth by the quantitative analyses of the number, distribution, and intensity of occlusal tooth contacts. These analyses were enabled by two diagnostic systems. The first system consists of an EMG biofeedback trainer and an image-processing device. The former enables the minimization of jaw muscle activities during light tooth tapping. The tooth contact position during the tapping is termed as the “physiological centric position” (PCP) because it is very stable and representative. The latter captures the translucent image of the check-bite, which is taken in the PCP, and quantitatively analyzes the number, position, and distribution of occlusal contacts. The other system is the bite force analyzing system that enables simultaneous recording of forces at multiple occlusal contact points during forceful clenching. In this paper, the author has described an actual scheme of normal dental occlusion based on these systems. The scheme includes parameters such as even and simultaneous contact of all posterior teeth, bilaterally symmetrical distribution of tooth contacts and occlusal loads, and larger and more intense tooth contact of the posterior teeth as compared with the anterior teeth. Based on these parameters, the biological–biomechanical interface of dental occlusion is discussed.

The distribution of occlusal contacts in the intercuspal position and temporomandibular disorder.

The aim of this study was to describe the distribution of occlusal contacts in subjects with signs or symptoms of temporomandibular disorder (TMD), and to assess whether any difference exists with healthy subjects. Twenty-five university dental students with complete natural dentition who exhibited TMD (13 females and 12 males, age from 19 to 30 years) and 25 age- and sex-matched controls entered the study. Occlusal contacts were evaluated in the intercuspal position and wax registrations were made in all subjects. Occlusal contacts were classified according to location and intensity. No differences were found between TMD and control groups for the overall number and distribution of contacts or for any side and intensity of contact. An intra-subject analysis showed that TMD subjects had significantly greater bilateral asymmetry in the number of contacts than controls. Median absolute difference of the number of contacts on right and left sides was 3 (95% CI, 2-4) in TMD subjects and 2 (95% CI, 1-2) in controls. In TMD subjects with mono-lateral TMD there was a significant concordance (88.9%) between the side of disorder and the side of higher number of contacts. These findings, while confirming that a significant relationship exists between distribution of occlusal contacts and TMD, further suggest that in young adults it may be primarily expressed by asymmetries in occlusal contact patterns. Existence and aetiology of any association of TMD with occlusal contacts should be further investigated.

A clinical and physiological evaluation of masticatory center in unilateral shortened arch and RPD treatment

The purpose of this study was to elucidate the relation between distribution of occlusal contacts in unilateral shortened arch and prosthodontic treatment, those occlusal loads, coordinates of the points and amounts, in relation to masticatory musculature activities by EMG and Prescale. Occlusal contacts and loads were measured by extra-thin-layer of pressure indicator (Prescale Fuji Film Co.), with an exclusive analyzing computer system. Masticatory muscular EMG and occlusal contacts were recorded with Prescale at i.p. clenching. Ten bilateral shortened arch-cases were used as control and fifteen unilateral shortened dental arches were studied in periodically at pre- and post-RPD treatments. These data were analyzed and evaluated in those of the control group. These results were as follows: 1) The location of the occlusal load center in dentate mouth was about median line of the maxillar first molar region, but in unilateral shortened arch the load center was biased about one premolar breadth anteriorly and inclined toward remaining dentate side. 2) The center of supporting area of unilateral shortened arch edentation was biased toward the remaining side and slightly to incisal arch. 3) After wearing eligible designed RPD for over one year, in the unilateral edentate arch, the location of the load center was improved at the dentate arch, presuming physiological and functional recovery, and also activated masticatory musculatures. 4) The prosthodontic restoration for unilateral edentate cases (unilateral shortened arch) was quite effective in clinical and physiological stand points.

Occlusal Contact Changes Before and After Orthodontic Treatment of a Group of Child &amp; Adolescent Patients with TMJ Disturbance

Abstract Occlusal contacts were examined before and after orthodontic treatment in 32 eight- to seventeen-years-old patients with temporomandibular joint disturbance. Add-Picture, a computer image system, was applied to a silicone occlusal record obtained in the intercuspal position (ICP) to assess the qualitative and quantitative changes of occlusal contacts. Comparing the two images before and after treatment, significant difference was noted in the number, size, location and type of contacts. After orthodontic treatment: the mean number of contacts on anterior teeth reduced, the mean area per contact decreased, the number of contacts on centric stops increased and type IV contacts (on the inclined plane) decreased. The present study indicates that orthodontic treatment has a positive effect, both qualitatively and quantitively, on the distribution of occlusal contacts in ICP and seems to contribute to the establishment of occlusal stability in ICP.

Distribution of occlusal contacts in maximum intercuspation

This study describes the use of the T-Scan system to record and analyze tooth contact data by calculating time moment statistics in the sagittal and transverse axes of the occlusal plane and reports the results of this method to analyze the occlusion of 93 normal subjects. Results confirm the findings of previous investigators and indicate that in a normal dentition there is a tendency for bilateral equality of the tooth contacts about the sagittal axis and that the center of effort for tooth contacts anteroposteriorly is located in the region of the first molar and is symmetrical bilaterally. Because of the rapid and accurate ability of the T-Scan system to identify the distribution of the tooth contacts, it shows great promise as a clinical diagnostic screening device for occlusion.