Assessment of the amount of tooth wear on dental casts and intra-oral photographs

Automated monitoring of tooth wear progression using AI on intraoral scans

OBJECTIVES

This study aimed to develop and evaluate a fully automated method for visualizing and measuring tooth wear progression using pairs of intraoral scans (IOSs) in comparison with a manual protocol.

METHODS

Eight patients with severe tooth wear progression were retrospectively included, with IOSs taken at baseline and 1-year, 3-year, and 5-year follow-ups. For alignment, the automated method segmented the arch into separate teeth in the IOSs. Tooth pair registration selected tooth surfaces that were likely unaffected by tooth wear and performed point set registration on the selected surfaces. Maximum tooth profile losses from baseline to each follow-up were determined based on signed distances using the manual 3D Wear Analysis (3DWA) protocol and the automated method. The automated method was evaluated against the 3DWA protocol by comparing tooth segmentations with the Dice-Sørensen coefficient (DSC) and intersection over union (IoU). The tooth profile loss measurements were compared with regression and Bland-Altman plots. Additionally, the relationship between the time interval and the measurement differences between the two methods was shown.

RESULTS

The automated method completed within two minutes. It was very effective for tooth instance segmentation (826 teeth, DSC = 0.947, IoU = 0.907), and a correlation of 0.932 was observed for agreement on tooth profile loss measurements (516 tooth pairs, mean difference = 0.021mm, 95% confidence interval = [-0.085, 0.138]). The variability in measurement differences increased for larger time intervals.

CONCLUSIONS

The proposed automated method for monitoring tooth wear progression was faster and not clinically significantly different in accuracy compared to a manual protocol for full-arch IOSs.

CLINICAL SIGNIFICANCE

General practitioners and patients can benefit from the visualization of tooth wear, allowing quantifiable and standardized decisions concerning therapy requirements of worn teeth. The proposed method for tooth wear monitoring decreased the time required to less than two minutes compared with the manual approach, which took at least two hours.

Reliability of the Assessment of Tooth Wear Severity on Dental Hard Tissues and Dental Restorations, Using the TWES 2.0, by Nonexperts

BACKGROUND

Tooth wear is a multifactorial process resulting in the loss of dental hard tissues. For its assessment, the tooth wear evaluation system (TWES) 2.0 has been published. Previous studies on the TWES involved well-trained practitioners, rather than nonexperts.

OBJECTIVE

The first aim of this study was to investigate the reliability of the assessment of tooth wear severity on dental hard tissues, using the TWES 2.0, by nonexperts. The second aim was to investigate the reliability of assessment of wear severity on dental restorations, using a third scale.

METHODS

Forty-seven dental students evaluated at least 9 of 14 possible patient cases on dental casts and intraoral photographs. Cohen's kappa (agreement with sample solution) and Fleiss' kappa (Inter-rater reliability) were calculated.

RESULTS

The agreements of the operators' ratings compared to the sample-solution resulted in Cohen's kappa between 0.02 and 0.9. The agreements were 0.34 for occlusal; 0.43 for vestibular; 0.57 for oral surfaces. Inter-rater reliability (Fleiss' kappa) was 0.35 for occlusal, 0.17 for vestibular and 0.24 for oral assessment. The inter-rater reliability of the ratings on tooth surfaces with restorations was lower with 0.21 (occlusal), 0.14 (vestibular) and 0.39 (oral). The agreement on different restorations differed tremendously.

CONCLUSIONS

The ability to correctly assess the cases varied considerably between individual examiners. Within the limits of this study, assessment of restorations was slightly more challenging compared to natural teeth, particularly in occlusal regions or when the restorative material is gold. Subsequent studies should address whether enhanced training and improved definition of tooth wear grades result in higher reliability scores.

Tooth Wear Evaluation System 2.0-Evaluation of diagnostic reliability in the assessment of signs and symptoms for tooth wear by non-experts

BACKGROUND

Tooth wear is a multifactorial condition that manifests through various signs and symptoms. These individual signs and symptoms were described in multiple studies, leading to the inclusion in TWES 2.0 (Tooth Wear Evaluation System 2.0) and the forthcoming DC-TW (Diagnostic Criteria for Tooth Wear). However, a study evaluating their reliability has yet to be conducted.

OBJECTIVE

The aim of the study was to examine the reliability in the assessment of 6 signs of pathological tooth wear and 18 clinical signs and symptoms determining aetiology, all of which are included in the TWES 2.0/DC-TW.

METHODS

48 dental students (operators) evaluated patient cases from a patient pool of 14 patients on dental casts and high-resolution intraoral photographs. The agreement between all operators for each sign and symptom was calculated based on ICC (Intraclass Correlation Coefficients). Additionally, the agreement of each operator's evaluation with a predefined sample solution was calculated based on Cohen's kappa.

RESULTS

Inter-user agreement ranged from near perfect (0.91) to poor (0.02) for the various pathology signs or aetiology symptoms of tooth wear (mean 0.32). The agreements of the operator's ratings compared to the sample solution resulted in Cohen's kappa from 0.18 to 1 (mean 0.59) for the pathology signs and ranged from 0.02 to 0.51 for the aetiology signs (mean 0.38).

CONCLUSIONS

The reliability of the signs and symptoms examined and the ability of individual investigators to correctly identify and assign signs and symptoms varied widely. The current assessment tools for the qualification of tooth wear need further refinement, and examiners need intensive training in tooth wear assessment.

Perception of oral health related quality of life and orofacial aesthetics following restorative treatment of tooth wear: A five-year follow-up

OBJECTIVES

Non-carious tooth wear often has a multifactorial etiology and may lead to functional or aesthetically related problems. The most common complaints associated with tooth wear are dissatisfaction with dental appearance and a negative impact on the experienced Oral Health Related Quality of Life (OHRQoL). The aim of this study was to investigate the change in OHRQoL and the perception of aesthetics, following restorative treatment of moderate to severe tooth wear patients, with a five-year follow-up.

METHODS

An explorative study, based on prospective data, was performed. OHRQoL and the perception of aesthetics were measured with the OHIP-NL and OES-NL. These questionnaires were completed before treatment, one month after treatment, and at 1-, 3- and 5-years post-treatment. Treatment involved full mouth reconstruction with composite resin restorations. The data was analysed as repeated measures by using a linear mixed-effects model.

RESULTS

One hundred and twenty-three tooth wear patients that received restorative rehabilitation were included (97 males, 26 females, 37.5 ± 8.8 years-old). Data showed a statistically significant increase in both experienced OHRQoL and orofacial appearance after restorative treatment. The OHIP-scores remained stable over time, while the OES-scores slightly decreased during the years after treatment. Regarding the seven domains of the OHIP, the largest difference in OHIP-score was found in the domain of 'Psychological Discomfort'. The mean overall OHIP-score was 1.8 at baseline and 1.3 at the 5-years recall. The mean OES score increased from 41.8 at baseline to 66.1 at the 5-years follow-up.

CONCLUSIONS

Tooth wear patients reported significant improvements in their OHRQoL and their perception of orofacial aesthetics after restorative treatment. This increase remained at least five years post-treatment.

CLINICAL SIGNIFICANCE

The clinical impact of restorative treatment for tooth wear patients is considerable. This paper emphasizes the need to include a discussion of the patient related outcome measures when planning care.

Clinical factors to consider in definitive treatment planning for patients with tooth wear

Diagnosis, disease control and prevention are the precursors to successful definitive restorative treatment of pathological tooth wear. This case series illustrates how proposed key clinical features can influence treatment complexity and provide the clinician with a logical sequence of treatment options for definitive management of tooth wear.

Prevalence and risk factors of erosive tooth wear among young adults in the Singapore military

OBJECTIVES

Erosive tooth wear (ETW) is defined as the irreversible chemo-mechanical loss of dental hard tissues without plaque or bacteria and has been a growing phenomenon in the general population worldwide. The aim of this study was to determine the prevalence of ETW and the associated risk factors among young military personnel in Singapore.

MATERIALS AND METHODS

This cross-sectional study consisted of a questionnaire and clinical examination of military personnel between 18 and 25 years. The questionnaire collected information on demographics, medical and dental history, lifestyle and dietary habits. Tooth wear was clinically evaluated using the Basic Erosive Wear Examination (BEWE) index. The participants were profiled into four risk categories (none, low, moderate, severe) based on the sum score. Multivariable logistic regression analysis was performed to determine the risk factors associated with the presence of ETW.

RESULTS

Out of 1296 participants evaluated, 21.8% of them had ETW. The anterior sextants were more affected by erosion than posterior sextants for both arches. The risk factors significantly associated with ETW were GERD (OR = 2.83, p = 0.041), presence of self-reported TMD symptoms (OR = 2.51, p < 0.001), acidic food (OR = 2.03, p < 0.001) and drinks (OR = 3.07, p < 0.001), high caries risk (OR = 4.59, p < 0.001) and toothbrush stiffness (OR = 4.67, p < 0.001).

CONCLUSION

ETW is prevalent among the young military population, with over half of the population at a risk of ETW. Gastric reflux disease, TMD, acidic diet, dental caries susceptibility and the use of stiff toothbrushes were identified as significant risk factors.

CLINICAL RELEVANCE

A large proportion of young military personnel exhibited mild to moderate risk of ETW. Dental professionals can identify risk-susceptible individuals at a young age and educated them with preventive measures and dietary interventions to prevent the progression of the condition.

Tooth Wear Evaluation System (TWES) 2.0-Reliability of diagnosis with and without computer-assisted evaluation

BACKGROUND

Tooth wear is a multifactorial process, leading to the loss of dental hard tissues. Therefore, it is important to detect the level of tooth wear at an early stage, so monitoring can be initiated. The Tooth Wear Evaluation System (TWES) enables such a multistage diagnosis of tooth wear. The further developed TWES 2.0 contains a complete taxonomy of tooth wear, but its reliability has not yet been validated.

OBJECTIVES

The aim of the study was to examine in a randomised controlled trial (RCT) whether diagnoses made based on the TWES 2.0 are reproducible and whether this reproducibility is also achieved with computer-assisted diagnostics.

METHODS

44 dental students received extensive training in TWES 2.0 assessment and taxonomy. The students each evaluated at least 10 (of the present 14) anonymised patient cases using gypsum models and high-resolution intra-oral photographs according to TWES 2.0. One half initially evaluated on paper; the other half used dedicated software (CMDfact / CMDbrux). After half of the patient cases (5), the evaluation methods were switched (AB/BA crossover design). The diagnoses were then evaluated for agreement with the predefined sample solution.

RESULTS

Evaluation of agreement with the sample solution according to Cohen's kappa indicated a value of 0.46 for manual (traditional) evaluation; and 0.44 for computer-assisted evaluation. Evaluation of agreement between examiners was 0.38 for manual and 0.48 for computer-assisted evaluation (Fleiss' kappa).

CONCLUSION

The results of this study proved that the taxonomy of the TWES 2.0 has acceptable reliability and can thus be used by dentists. Accordingly, the system can be learned quickly even by untrained practitioners. Comparable results are achieved with computer-assisted evaluation.

The effect of pre-treatment levels of tooth wear and the applied increase in the vertical dimension of occlusion (VDO) on the survival of direct resin composite restorations

OBJECTIVES

To investigate the effects of the level of pre-treatment tooth wear and increasing the VDO on the performance of direct resin composite restorations for the rehabilitation of pathological tooth wear.

METHODS

Full-mouth (pre-treatment) grading was performed on digital greyscale scan records for 34 participants (35.3 ± 8.4 years) with signs of moderate-to-severe generalised tooth wear, using the Tooth Wear Evaluation System and the Basic Erosive Wear Examination. Each participant received full-mouth direct resin composite restorations, with increased VDO. The post-treatment increase in the VDO was determined. Recalls were planned after 1 month, and after 1, 3, and 5 years. Three 'levels' of restoration failure were described. The effects of the variables on the frequencies of restoration failure were calculated with a multivariable Cox regression, (p < 0.05).

RESULTS

1269 restorations were placed with a mean observation period of 62.4 months. Increasing the VDO by 1 mm significantly reduced the risks of all levels of anterior restoration failure (HR ≤ 0.62, p ≤ 0.025). A higher anterior BEWE surface score was associated with increased risks of Level 2- & 3- failures, (HR ≥ 1.29, p ≤ 0.019). Premolar restorations showed lower risks of Level 2- & 3- failure, compared to the molar restorations, (HR ≤ 0.5, p ≤ 0.005).

CONCLUSION

Levels of pre-treatment wear and the applied change in the VDO significantly affected failure risk.

CLINICAL RELEVANCE

Direct resin composite restorations for the rehabilitation of wear should be made as voluminous as possible, respecting the presenting biological, functional, and esthetic constraints.

A comparative evaluation between the reliability of gypsum casts and digital greyscale intra-oral scans for the scoring of tooth wear using the Tooth Wear Evaluation System (TWES)

Background

The Tooth Wear Evaluation System (TWES) is a type of tooth wear index. To date, there is the lack of data comparing the reliability of the application of this index on gypsum cast records and digital greyscale intra‐oral scan records.

Objectives

A comparative evaluation between the use of gypsum cast records and digital greyscale intra‐oral scan records with the reliability of tooth wear scoring using the TWES amongst a group of patients with tooth wear.

Methods

Records for 10 patients with moderate to severe tooth wear (TWES ≥ 2) were randomly selected from a larger clinical trial. TWES grading of the occlusal/incisal, buccal and palatal/lingual surfaces was performed to determine the levels of intra‐ and interobserver agreement. Intra‐observer reproducibility was based on the findings of one examiner only. For the interobserver reproducibility, the findings of two examiners were considered. One set of models/ records were used per patient. Cohen's weighted kappa (κ_W) was used to ascertain agreement between and within the observers. Comparison of agreement was performed using t tests (P < .05).

Results

For the scoring of the of the total occlusal/incisal surfaces, the overall levels of intra‐ and interobserver agreement were significantly higher using the gypsum cast records than with the digital greyscale intra‐oral scan records, (P < .001) and (P < .001), respectively. For the overall buccal surfaces, only a significant difference was found in the intra‐observer agreement using gypsum casts, (P = .013). For the palatal/lingual surfaces, a significant difference was only reported in the interobserver agreement using gypsum casts, (P = .043). At the occlusal/incisal surfaces, grading performed using gypsum casts, culminated in significantly higher TWES scores than with the use of the digital greyscale intra‐oral scans (P < .001). At the buccal and palatal/lingual surfaces, significantly higher wear scores were obtained using digital greyscale intra‐oral scan records (P < .009).

Conclusions

The TWES can offer a reliable means for the scoring of wearing occlusal/incisal surfaces using gypsum casts. The reliability offered by digital greyscale intra‐oral scans for consecutive scoring was in general, inferior.

Diagnosing tooth wear, a new taxonomy based on the revised version of the Tooth Wear Evaluation System (TWES 2.0)

Background

Tooth wear is a multifactorial condition, leading to the loss of dental hard tissues. Physiological tooth wear is a slow process that normally does not lead to any subjective symptoms. When the condition progresses, it can become pathological, and several signs and symptoms may occur. The Tooth Wear Evaluation System (TWES) was described to implement a systematic diagnostic and management approach. Recently, management guidelines were presented in a European Consensus Statement (ECS) as well.

Objectives

To evaluate the TWES in practice and to integrate the principles described in the ECS in order to compose a renewed TWES 2.0 and a new taxonomy.

Methods

The TWES and the recommendations of the ECS were used by dental clinicians, in order to test its applicability in practice.

Results

Agreement was reached that the TWES 2.0 will use a stepwise approach, with a straightforward Tooth Wear Screening part and a more detailed Tooth Wear Status part. Also, the assessment of pathology from the ECS is incorporated in the TWES 2.0 (both classification and taxonomy).

Conclusions

In the TWES 2.0 is described that tooth wear is pathological if moderate/severe/extreme tooth wear is present, in combination with one or several described signs and symptoms. Aetiology can be assessed by findings that indicate a chemical and/or a mechanical cause. The taxonomy may help to identify situations in which preventive (restorative) interventions in early stages of tooth wear can be indicated. The reliability and validity of the adapted parts must be proven.

A methodology for evaluating tooth wear monitoring using timed automata modelling

OBJECTIVES

Tooth wear is a multifactorial condition leading to the loss of dental hard tissues. A counselling/monitoring protocol is of importance in order to keep that loss as limited as possible. Since many factors are involved and a time span of decades is included, research to disentangle all these processes in patients is difficult. Instead, a modelling technique was used that is able to deal with time, costs and probabilistic and stochastic information. The aim was to shed light on the question: does a yearly or a once-in-five-years counselling/monitoring protocol yield better outcome measures?

METHODS

A so-called timed automata model was adopted, analysed with the tool UPPAAL. To our knowledge, this is the first time that formal modelling is applied in dentistry. In this article, a UPPAAL model for the evaluation of tooth wear is described.

RESULTS

Using the UPPAAL model, it was calculated that with a yearly counselling/monitoring protocol the severity of tooth wear at age 74, the total costs per person and the number of restorative treatments were less, and the number of so-called "good years" was higher.

CONCLUSIONS

With the use of the UPPAAL model, it may be concluded that a yearly counselling/monitoring protocol can yield better outcome measures.

CLINICAL SIGNIFICANCE

Regarding dentistry in general and tooth wear in particular, with the use of a timed automata model in UPPAAL, actual research questions can be answered, factors of influence in a multifactorial condition like tooth wear can be clarified, and future research topics can be determined.

Diagnostic Value of the Basic Erosive Wear Examination for the Assessment of Dental Erosion on Patients, Dental Photographs, and Dental Casts

OBJECTIVES

The aim of this trial was to investigate the diagnostic value of the basic erosive wear examination (BEWE) in clinical use, on dental photographs, and on dental casts over a two-year follow-up period (2013-2015). According to the main hypothesis for longitudinal monitoring of dental erosion, the BEWE is equally reproducible by the three assessment methods.

METHODS AND MATERIALS

The clinical assessment included intraoral photographic documentation, dental impressions, oral examination, and assessment of BEWE. Clinical assessment of BEWE was done by one blinded examiner, whereas assessment on photographs and dental casts was performed by three calibrated examiners and repeated after 14 days. The three assessment methods were analyzed separately by longitudinal agreement and inter- and intrarater reliability (intraclass correlation coefficient) alongside 95% confidence intervals (CIs).

RESULTS

Comparing the longitudinal data of the years 2013-2015, clinical use and photographs showed no significant difference (p=0.0681-0.9963), whereas the statistical analysis showed a significant difference for dental casts by comparing data from 2013 vs 2014 (p=0.0266) as well as data from 2013 vs 2015 (p=0.0001). Statistical evaluation of overall BEWE showed an intrarater reliability of 0.79-0.91 for photographs and 0.60-0.87 for dental casts. The interrater reliability was 0.77 (95% CI=[0.69; 0.84]) for photographs and 0.63 (95% CI=[0.52; 0.72]) for dental casts.

CONCLUSION

This investigation showed that in longitudinal clinical monitoring, the assessment of the BEWE on patients and dental photographs yielded comparable results. In addition, based on these findings, the assessment of the BEWE on dental casts showed moderate reproducibility. Therefore, dental casts may be better used for laboratory assessment techniques.

Monitoring the progression of erosive tooth wear (ETW) using BEWE index in casts and their 3D images: A retrospective longitudinal study

OBJECTIVE

To determine if the Basic erosive tooth wear index (BEWE index) is able to assess and monitor ETW changes in two consecutive cast models, and detect methodological differences when using the corresponding 3D image replicas.

METHODS

A total of 480 pre-treatment and 2-year post-treatment orthodontic models (n = 240 cast models and n = 240 3D image replicas) from 120 adolescents treated between 2002 and 2013 at the Gent Dental Clinic, Belgium, were scored using the BEWE index. For data analysis only posterior sextants were considered, and inter-method differences were evaluated using Wilcoxon Signed Rank test, Kappa values and Mc Nemar tests (p < 0.05). Correlations between methods were determined using Kendall tau correlation test.

RESULTS

Significant changes of ETW were detected between two consecutive models when BEWE index was used to score cast models or their 3D image replicas (p < 0.001). A strong significant correlation (τb: 0.74; p < 0.001) was shown between both methods However, 3D image-BEWE index combination showed a higher probability for detecting initial surface changes, and scored significantly higher than casts (p < 0.001). Incidence and progression of ETW using 3D images was 13.3% (n = 16) and 60.9% (n = 56) respectively, with two subjects developing BEWE = 3 in at least one tooth surface.

CONCLUSIONS

BEWE index is a suitable tool for the scoring of ETW lesions in 3D images and cast. The combination of both digital 3D records and index, can be used for the monitoring of ETW in a longitudinal approach. The higher sensibility of BEWE index when scoring 3D images might improve the early diagnosis of ETW lesions.

CLINICAL SIGNIFICANCE

The BEWE index combined with digital 3D records of oral conditions might improve the practitioner performance with respect to early diagnosis, monitoring and managing ETW.

The influence of management of tooth wear on oral health-related quality of life

Objective

The purpose of this study was to identify the level of oral health-related quality of life and orofacial appearance in patients with moderate to severe tooth wear. Patients with and without a request for restorative treatment were included.

Methods

One hundred twenty-four patients (98 men, 26 women, mean age: 40.5 ± 8.8 years) with moderate to severe tooth wear were included. Patients without a request for help received a non-restorative treatment of counseling and monitoring. Patients with a request for restorative treatment were treated with a full rehabilitation using composite resin restorations. Oral Health Impact Profile (OHIP-NL) and Orofacial Esthetic Scale (OES-NL) questionnaires were filled in at baseline and after 1 year.

Results

Counseling and monitoring group: baseline OHIP-NL score was 0.4 ± 0.3, baseline summary score of OES-NL was 48 ± 7.0, and baseline impression score was 7.1 ± 1.2. Scores had not changed significantly after 1 year (p = 1.00 after Bonferroni correction).Restoration group: baseline OHIP-NL score was 0.8 ± 0.6, baseline summary score of OES-NL was 38 ± 10, and baseline impression score was 5.9 ± 1.5. Scores had improved significantly after 1 year (p < 0.001 after Bonferroni correction).

Conclusions

Counseling and monitoring did not result in a significant deterioration and restorative treatment resulted in a significant improvement of oral health-related quality of life (OHRQoL) and orofacial appearance in this patient group.

Clinical significance

In patients with moderate to severe tooth wear, without functional and esthetical problems, counseling and monitoring may be an appropriate treatment option. Restorative treatment in patients with a need for treatment results in an improved OHRQoL. OHIP and OES questionnaires may be used to monitor changes in clinically relevant symptoms.