Computerized occlusal analysis: correlation with occlusal indexes to assess the outcome of orthodontic treatment or the severity of malocculusion

Reference values and reliability of occlusal force distribution and occlusal time measured by the T-Scan system in adults with healthy dentition

PURPOSE

Reference values of occlusal characteristics are needed to interpret the data obtained using the T-Scan System. This study aimed to establish reference values for and to assess the reliability of, occlusal force distribution in the maximal intercuspal position and the occlusion time in young adults with healthy dentition.

MATERIALS AND METHODS

In total 178 adults with natural dentition participated in this retrospective cross-sectional study, of whom 76 performed a retest session. Several occlusal recordings were obtained from each participant using the T-Scan system while asking them to bite two or three consecutive times (multi-bite) or only once (single-bite) at the maximal intercuspal position. The lateral and anteroposterior occlusal force distribution were determined as percentages in the right and posterior teeth . Occlusion time was measured in seconds. After the occlusal force distribution and occlusion time percentiles were calculated, reliability was assessed by the intraclass correlation coefficient.

RESULTS

The 5th-95th percentiles for occlusal force distribution were 34%-67% on the right teeth and 55%-94% on the posterior teeth. The 90th percentile for multi-bite occlusion time was 0.17 s and for single-bite occlusion time was 0.27 s. The intraclass correlation coefficients for lateral occlusal force distribution, anteroposterior occlusal force distribution, multi-bite occlusion time, and single-bite occlusion time were 0.70, 0.68, 0.58, and 0.67, respectively.

CONCLUSIONS

This study generated reference values for key occlusal characteristics (occlusal force distribution and occlusion time) when using the T-Scan system. These values showed moderate reliability.

Evaluation of occlusal bite force distribution by T-Scan in orthodontic patients with different occlusal characteristics: a cross sectional-observational study

BACKGROUND

The aim of orthodontic treatment, apart from esthetic and functional corrections, is uniform force distribution. Hence Occlusal analysis using a T scan gives scope for a precisely targeted treatment plan. The T-scan evaluation of occlusal force, time, and location of contacts from initial occlusal contact to maximum intercuspation enables the orthodontist to sequentially balance the occlusal forces on the right and left sides through specific treatment plan options.

OBJECTIVE

The current study aimed to determine the force distribution in the different individuals by using a T-Scan as well as the net discrepancies of forces generated at a maximum intercuspation position in the first molar region between the left and right sides of the mouth.

METHODS

This is a descriptive-correlational study that was carried out in Ras Al Khaimah College of Dental Sciences clinics and Ajman University clinics from January 2020 to September 2022 by using the convenience sampling technique. The T-scan III Novus was employed in this investigation to record multi-bite scans for several patients. T-scan was utilised to examine various malocclusions.

RESULTS

The present study consisted of 158 participants. Analysis of Variance (ANOVA) showed that there is a statistically significant difference in the percentage of force between the three types of malocclusions (I, II, and III) on the right molar side (B-16 and B-46) (p < 0.05). Moreover, the overall discrepancy showed a statistically significant difference in the three types of malocclusion classifications (p < 0.05). On the other hand, there was no statistically significant difference in the percentage of force between B-26 and B-36 (p > 0.05). Post hoc analysis showed a statistically significant difference in the percentage of force between malocclusion classes I and III on the right molar, with a mean difference of 4.11190 (p < 0.05). Similarly, there was a statistically significant difference in B-46 between Malocclusion Classes I and II, 4.01806 (p < 0.05). Additionally, post hoc analysis showed a statistically significant difference between malocclusion classes I and III, with a mean difference of -4.79841 (p < 0.05) on the right molar.

CONCLUSION

The T-Scan is a useful tool for assessing occlusal discrepancies and can be helpful during treatment planning and follow-up, especially for orthognathic surgery patients. A T-scan could be used in orthodontic therapy in a simple and efficient way. Also, it turned out to be a useful tool for diagnosing problems and gave us new information about how therapies work. In this study, T-Scan showed that it can measure occlusal forces in timing in an objective, accurate, and repeated manner. The current study found that T-Scan was better able to report the difference in the percentage of force on the right molar side than on the left side.

Three-dimensional evaluation of a virtual setup considering the roots and alveolar bone in molar distalization cases

We aimed to evaluate root parallelism and the dehiscence or fenestrations of virtual teeth setup using roots isolated from cone beam computed tomography (CBCT) images. Sixteen patients undergoing non-extraction orthodontic treatment with molar distalization were selected. Composite teeth were created by merging CBCT-isolated roots with intraoral scan-derived crowns. Three setups were performed sequentially: crown setup considering only the crowns, root setup-1 considering root alignment, and root setup-2 considering the roots and surrounding alveolar bone. We evaluated the parallelism and exposure of the roots and compared the American Board of Orthodontics Objective Grading System (ABO-OGS) scores using three-dimensionally printed models among the setups. The mean angulation differences between adjacent teeth in root setups-1 and -2 were significantly smaller than in the crown setup, except for some posterior teeth (p < 0.05). The amount of root exposure was significantly smaller in root setup-2 compared to crown setup and root setup-1 except when the mean exposure was less than 0.6 mm (p < 0.05). There was no significant difference in ABO-OGS scores among the setups. Thus, virtual setup considering the roots and alveolar bone can improve root parallelism and reduce the risk of root exposure without compromising occlusion quality.

Computerized dynamic occlusal analysis and its correlation with static characters in post-orthodontic patients using the T-Scan system and the ABO objective grading system

OBJECTIVES

This study was conducted to detect the overall performance of both static and dynamic occlusion in post-orthodontic patients using quantified methods, and to ascertain the correlation between the two states of occlusion.

MATERIALS AND METHODS

A total of 112 consecutive patients evaluated by ABO-OGS were included in this study. Based on the pre-treatment Angle's classification of the malocclusion, samples were divided into four groups. After removing orthodontic appliances, each patients underwent the American Board of Orthodontic objective grading system (ABO-OGS) and T-Scan evaluations. All the scores were compared within these groups. Statistical evaluation included reliability tests, multivariate ANOVA, and correlation analyses (p < 0.05 was considered significant).

RESULTS

The mean ABO-OGS score was satisfactory and did not differ by Angle classifications. The indices making substantial contributions to ABO-OGS were occlusal contacts, occlusal relationships, overjet, and alignment. Disocclusion time in post-orthodontic patients was longer than normal. Occlusion time, disocclusion time, and force distribution during dynamic motions were considerably influenced by static ABO-OGS measurements, especially occlusal contacts, buccolingual inclination, and alignment.

CONCLUSION

Post-orthodontic cases that passed the static evaluation of clinicians and ABO-OGS may nevertheless be left with dental casts interference in dynamic motions. Both static and dynamic occlusion should be extensively evaluated before ending orthodontic treatment. Further research is needed on dynamic occlusal guidelines and standards.

Evaluation of occlusion parameters using T-scan III in patients receiving fixed orthodontic treatment

Objectives:

The aim of this study is to examine the relationship between occlusal factors and temporomandibular joint diseases (TMD).

Material and Methods:

In our study, 43 individuals who had fixed orthodontic treatment and 20 individuals who did not need treatment at Istanbul Aydin University Faculty of Dentistry Department of Orthodontics were included in the study. Evaluations were made at the beginning of treatment (T0) and at 6 months (T1). T-Scan® computerized Occlusion Analyzer was used to evaluate the number of contact points, occlusal force parameters during centric occlusion and lateral movements, and occlusion and disclusion times. Differences between groups were evaluated with Mann–Whitney or independent t-test, and within-group differences were evaluated with Wilcoxon sign test or paired t-test, depending on whether the data showed normal distribution or not.

Results:

There was no statistically significant distinction between the gender-based parameters and right and left joint of Joint Vibration Analysis record in all three groups (P > 0.05). At the beginning of orthodontic treatment, there was no statistical difference in the variables within the group and between the groups. As a result of the comparison between the beginning of treatment (T0) and the 6th month (T1), no significant difference was found between the parameters of the anterior/posterior occlusal force distribution of the right-left quadrant and the force distribution of the working and non-working sides in lateral movements, and the occlusion and disclusion time parameters. Maximum intercuspal position left/right (MxlntlTSCANT1) was found to be statistically significant at 6 months in individuals who received fixed orthodontic treatment with extraction compared to the none xtraction treatment group (P < 0.05).

Conclusion:

According to our research, T-scan is one of the best devices for the early detection of TMD, especially for people undergoing orthodontic treatment. T-scan offers fast, non-invasive, and repeatable occlusion recording.

Examination of chewing performance with extraction and non-extraction fixed orthodontic treatment – A prospective clinical 1-year study

Objectives:

It shows that patients receiving orthodontic treatment may have a risk of developing temporomandibular disorder symptoms. The aim of this study is to examine the changes in the chewing system of occlusal contact parameters related to joint vibrations, chewing patterns, and measured excursive movements in fixed and non-extractive orthodontic treatments.

Material and Methods:

A total of 43 individuals with premolar extraction (n = 23) and without extraction (n = 20) who applied to the Department of Orthodontics, Dentistry Faculty of Istanbul Aydin University and needed orthodontic treatment were included in the study. In this study, 43 active fixed orthodontic treatment patients were conducted at the beginning (T0) and 6th month (T1) and 12th month (T2) on the parameter recorded during chewing. For occlusion analysis, T-Scan® computerized occlusion analysis recording and examination of the chewing pattern were used for JVA and JT temporomandibular joint parameters. Depending on whether the data showed normal distribution or not, differences between groups were evaluated using the Mann–Whitney or independent t-test, and intragroup differences were evaluated using the Wilcoxon sign test or paired t-test.

Results:

At the beginning, 6th month and 12th month of orthodontic treatment, it was observed that the opening, closing, and occlusion times and joint vibration frequencies in the chewing pattern in cases with and without tooth extraction, the integral value differences of total integral, and frequencies below 300 Hz and above 300 Hz were statistically significant (P < 0.001). In digital occlusion analysis values, the right-left differences were not found statistically significant in the measurements made in cases with and without extraction (P > 0.05), while there were statistically significant differences in disclusion values at the beginning, 6th and 12th months (P < 0.05).

Conclusion:

At the beginning of the orthodontic treatments with or without extraction, it was observed that the values at the joint level changed significantly in the 6th month. However, the changes in the joints during the treatment, when they return to their ideal values at the end of the 12th month, are more than the change in occlusion.

American Board of Orthodontics (ABO) Discrepancy Index and peer assessment rating (PAR) index with models versus photographs

BACKGROUND

The objectives of this study were to determine whether rating systems, such as the Peer Assessment Rating (PAR) and the American Board of Orthodontics Objective Grading System (ABO-OGS) can be applied to intraoral photographs.

METHODS

Models and photographs of 50 cases were graded by 4 raters, and a 20% repeat of randomized cases was completed 2 weeks later. Intraclass correlation coefficients (ICCs) were used to assess inter- and intra-rater agreements, as well as the level of agreement between the ratings on models and photographs.

RESULTS

The intra- and inter-rater agreements were considered good to excellent. The paired mean difference (model minus photo) for the PAR index and the ABO Discrepancy Index as a total was 2.405 and 1.156, respectively. Overjet was the subdomain that produced the highest differences between photos and models. The ABO- Discrepancy Index method on photographs was more reliable than the PAR index when grading pre-treatment and more-severe malocclusions.

CONCLUSIONS

Both methods can be used, but the choice depends on the purpose of the evaluation, and on consideration of the weaknesses and strengths of each relating to its use on photographs.

Digital occlusal analysis of pre and post single posterior implant restoration delivery: A pilot study

Objectives

The purposes of this study were to analyze the effects of single posterior implant restorations delivery on the redistribution of bite force and to evaluate the changes in occlusal force distribution of prostheses and potential influencing factors on occlusion variation at different stages.

Materials and methods

Thirty-two single posterior restorations in 30 participants (18 women and 12 men aged 27 to 75 years) were placed into either a unilateral single-tooth defect (n = 17) or on either side of a bilateral teeth defects (n = 15). The bite force (%) of the prostheses, teeth and segments at the maximum intercuspation position (MIP) was evaluated using a T-scan at 5 stages (pre-placement, immediately following placement, and 2 weeks, 3 months, and 6 months post-placement).

Results

The occlusal force of implant-supported prostheses was significantly (P = .000) lower than those of the control natural teeth at the baseline, then no significant difference was found with that of the mesial teeth at 3 months, and finally it was significantly (P = .000) lower than that of the distal teeth at 6 months; meanwhile, it significantly (P = .008) increased by a mean of 2.04 times from 2 weeks (3.39 ± 2.61%) to 3 months (6.90 ± 4.77%), whereas no significant difference (P = .900) was found from 3 months (6.90 ± 4.77%) to 6 months (7.31 ± 4.60%). In addition, the bite force of the posterior segment on the restored side of both unilateral and bilateral gaps was significantly (P = .013,.001) improved by 3.31% and 6.83%, respectively, although the discrepancy in bite force significantly (P = .039) increased from an initial 3.52% to 5.02% for subjects with bilateral defects, accompanying increases in the proportion (15.38%) of the level III bilateral bite force deviation (P >.05).

Conclusions

Bite force and masticatory ability can be improved with the immediate delivery of a single posterior implant restoration. The bite force distributed on the implant prosthesis inevitably increases after placement of implant prostheses, a routine follow-up and occlusal evaluation are strongly needed.

Restoration of the dentition in a patient with a history of bruxism and amelogenesis imperfecta: A clinical report

The report describes a 27-year-old female patient with amelogenesis imperfecta (AI) accompanied by nocturnal bruxism, who was treated with a combination of occlusal splint and full-mouth fixed prosthetic rehabilitation through follow-ups within 2 years. Soft splint protection, regular follow-up, and monitoring of carries are guaranteed to maintain a long-term curative effect.

Computerized Assessment of Occlusion and Muscle Activity during Use of a Multilayer Clear Retainer: A Preliminary Study

The aim of this preliminary study was to evaluate the short-term changes of occlusal contacts and muscle activity after orthodontic treatment during the use of a multi-layer clear retainer. Evaluation was done with the T-scan and BioEMG systems. A total of 18 subjects were included, who were evaluated at three time intervals-T0 at debonding, T1 at one month after retainer delivery, and T2 at four months after retainer delivery. The T-scan and electromyography (EMG) data were recorded simultaneously. The T-scan system recorded the occlusion time, disclusion time and force distribution. The EMG waves were quantified by calculating the asymmetry index and activity index. The time variables changed but not significantly. Occlusal force decreased in the anterior dentition and increased in the posterior dentition during T0-T2. There was no clear evidence of a relationship between unbalanced occlusal forces and muscle activity. In most subjects, the temporalis anterior muscle was more dominant than the masseter muscle. From this preliminary computerized study, there were no significant changes in the state of the occlusion or muscle activity during the short-term retention period.

Determination of the reliability and repeatability of a quantitative occlusal analyzer by using a piezoelectric film sensor: An in vitro study

STATEMENT OF PROBLEM

A digital quantitative occlusal analyzer with claimed lower cost and easier maneuverability has been introduced to replace conventional methods. However, information regarding its performance is scarce.

PURPOSE

The purpose of this in vitro study was to evaluate the reliability and repeatability of a newly introduced digital occlusal analysis device (Accura) and to compare it with an established occlusal analyzer (T-scan Novus).

MATERIAL AND METHODS

The sensor films of both devices were positioned between titanium maxillary and mandibular models that were equilibrated and arbitrarily mounted on a semiadjustable articulator. Compressive force was applied to the upper arm of the articulator with a universal testing machine, increased gradually to 50 N, and then released automatically. The time and force measurements from the universal testing machine and the tested devices were recorded by operating software programs. Five articulating film sensors of each device were tested 3 times each by 2 examiners and were repeated on consecutive days, totaling 60 trials per device. Reliability was defined as an agreement between the loaded force and measured force. Repeatability was defined as an agreement between repeated measurements of the Accura and T-scan Novus. Intraclass correlation coefficient was calculated for the statistical analysis (α=.05).

RESULTS

The calculated intraclass correlation coefficient of the Accura and the universal testing machine was 0.952. The intraclass correlation coefficient of the T-scan Novus and the universal testing machine was 0.963. Intraclass correlation coefficients that were calculated to compare the data acquired from different days were 0.938 for the Accura and 0.911 for the T-scan Novus.

CONCLUSIONS

The experimental results indicated that the reliability of both the Accura and T-scan Novus was excellent for measuring occlusal forces. In addition, both the Accura and T-scan Novus exhibited excellent repeatability.

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.

Comparison between conventional and computerised methods in the assessment of an occlusal scheme

PURPOSE

In the definition of an occlusal scheme, clinicians should choose between conventional and computerised methods based on a careful appraise of the advantages and limitations. This study aims to assess the correlation between the two approaches in a clinical setting.

METHODS

Twenty-four patients were included to compare different methods of occlusal contacts assessment on the posterior surfaces of flat mandibular appliances. In supine position, they were asked to clench with maximum strength, in the maximum intercuspation position with a 24 μm articulating paper positioned between the teeth and the appliance surface. An extra-oral photograph of the marks was taken (total N = 2082). They were visually classified based on a pre-defined scale (ie, conventional assessment) and with ImageJ analysis software (ie, photographic software assessment). Additionally, a computerised occlusal analysis was performed (ie, computerised assessment). Correlation analysis of the data achieved with conventional, photographic and computerised assessments was performed.

RESULTS

Correlation between conventional and computerised assessments was weak (r = .265), whilst it was moderate between conventional and photographic assessments (r = .633), as well as between photographic and computerised assessments (r = .476).

CONCLUSIONS

This investigation showed a weak-to-moderate correlation between different methods (ie, conventional, photographic and computerised) to assess occlusal marks. None of the three can actually be considered the standard of reference, but based on their specific features, it can bet suggested that the conventional method may be enough for most clinical purposes, unless otherwise proven.

Changes in occlusal function after extraction of premolars: 2-year follow-up

OBJECTIVE

To determine the effects of extraction and the number of teeth extracted on changes in occlusal function by measuring occlusal contact area and force before and after orthodontic treatment with a fixed appliance.

MATERIALS AND METHODS

Female patients treated with a fixed appliance were divided into nonextraction (n = 36), two maxillary premolar extraction (n = 31), and four premolar extraction (n = 18) groups. Bite pressure-sensitive films were used to analyze the occlusal contact area and force. Measurements were performed before treatment (Pre-Tx), immediately afterward (After-Tx), and 2 years later (2Y After-Tx). The data were analyzed using a linear mixed model and the post hoc Bonferroni test.

RESULTS

The occlusal contact area and force after treatment decreased significantly compared with Pre-Tx values but were increased 2 years later in all groups. There were no significant differences in occlusal contact area or force during the entire observation period among the three groups (P > .05). The occlusal contact area and force in the nonextraction and two maxillary premolar extraction groups recovered to Pre-Tx levels 2 years later (P > .05). The occlusal contact area in the four premolar extraction group was significantly lower than the Pre-Tx level after 2 years of retention (P < .05).

CONCLUSIONS

The occlusal contact area and force showed a tendency to decrease immediately after treatment and then gradually increase to pretreatment levels during the observation period. However, the occlusal contact area did not recover fully after 2 years in the four premolar extraction group.

The Improvement and Completion of Outcome index: A new assessment system for quality of orthodontic treatment

Objective

Given the considerable disagreement between the Peer Assessment Rating (PAR) index and the American Board of Orthodontics Cast-Radiograph Evaluation, we aimed to develop a novel assessment system―the Improvement and Completion of Outcome (ICO) index―to evaluate the outcome of orthodontic treatment.

Methods

Sixteen criteria from 4 major categories were established to represent the pretreatment malocclusion status, as well as the degree of improvement and level of completion of outcome during/after treatment: dental relationship (arch length discrepancy, irregularity, U1-SN, and IMPA); anteroposterior relationship (overjet, right and left molar position, ANB); vertical relationship (anterior overbite, anterior open-bite, lateral open-bite, SN-MP); and transverse relationship (dental midline discrepancy, chin point deviation, posterior cross-bite, occlusal plane cant). The score for each criterion was defined from 0 or −1 (worst) to 5 (ideal value or normal occlusion) in gradations of 1. The sum of the scores in each category indicates the area and extent of the problems. Improvement and completion percentages were estimated based on the pre- and post-treatment total scores and the maximum total score. If the completion percentage exceeded 80%, treatment outcome was considered successful.

Results

Two cases, Class I malocclusion and skeletal Class III malocclusion, are presented to represent the assessment procedure using the ICO index. The difference in the level of improvement and completion of treatment outcome can be clearly explained by using 2 percentage values.

Conclusions

Thus, the ICO index enables the evaluation of the quality of orthodontic treatment objectively and consecutively throughout the entire treatment process.