Quantitative tooth wear analysis of index teeth compared to complete dentition

Assessing tooth wear progression in non-human primates: a longitudinal study using intraoral scanning technology

Intraoral scanners are widely used in a clinical setting for orthodontic treatments and tooth restorations, and are also useful for assessing dental wear and pathology progression. In this study, we assess the utility of using an intraoral scanner and associated software for quantifying dental tissue loss in non-human primates. An upper and lower second molar for 31 captive hamadryas baboons (Papio hamadryas) were assessed for dental tissue loss progression, giving a total sample of 62 teeth. The animals are part of the Southwest National Primate Research Center and were all fed the same monkey-chow diet over their lifetimes. Two molds of each dentition were taken at either two- or three-year intervals, and the associated casts scanned using an intraoral scanner (Medit i700). Tissue loss was calculated in WearCompare by superimposition of the two scans followed by subtraction analysis. Four individuals had dental caries, and were assessed separately. The results demonstrate the reliability of these techniques in capturing tissue loss data, evidenced by the alignment consistency between scans, lack of erroneous tissue gain between scans, and uniformity of tissue loss patterns among individuals (e.g., functional cusps showing the highest degree of wear). The average loss per mm2 per year for all samples combined was 0.05 mm3 (0.04 mm3 for females and 0.08 mm3 for males). There was no significant difference in wear progression between upper and lower molars. Substantial variation in the amount of tissue loss among individuals was found, despite their uniform diet. These findings foster multiple avenues for future research, including the exploration of wear progression across dental crowns and arcades, correlation between different types of tissue loss (e.g., attrition, erosion, fractures, caries), interplay between tissue loss and microwear/topographic analysis, and the genetic underpinnings of tissue loss variation.

Intraoral Scanning for Monitoring Dental Wear and Its Risk Factors: A Prospective Study

Dental wear arises from mechanical (attrition or abrasion) and chemical (erosion) factors. Despite its prevalence and clinical significance, accurately measuring and understanding its causes remain challenging in everyday practice. This one-year study with 39 participants involved comprehensive examinations and full-arch intraoral scans at the start and after 12 months. Volume loss exceeding 100 µ on each tooth's surfaces (buccal, lingual/palatine and incisal/occlusal) was measured by comparing three-dimensional scans from both time points. This study also assessed factors such as abrasion and erosion through clinical exams and questionnaires. There were no significant differences in dental wear in participants with sleep bruxism. However, noticeable wear occurred in the front teeth of those with waking bruxism and joint-related symptoms. Increased wear was associated with frequent consumption of acidic drinks, regular swimming, dry mouth, nocturnal drooling and heartburn, while no significant wear was found in patients with reflux. The used methodology proved effective in accurately assessing the progression of dental wear, which is important as many patients may initially be asymptomatic. The variability observed in dental wear patterns underscores the need to develop specific software applications that allow immediate and efficient comparison of wear areas based on extensive analysis of patient databases.

Long-term occlusal tooth wear at the onset of permanent dentition

OBJECTIVES

This study quantified the long-term occlusal wear in the natural posterior teeth and the associations per tooth type within the dentition.

METHODS

The sample included 70 orthodontically treated subjects (52 females and 18 males; median age, 14.3 years), followed for a 12.7-year period. They were consecutively selected with no tooth wear-related criteria. Post-treatment (T1) and follow-up dental casts (T2) were scanned and superimposed through three-dimensional methods. Occlusal wear volume of posterior teeth and tooth wear patterns were investigated through non-parametric statistics and analysis of covariance.

RESULTS

There were no significant differences between contralateral teeth. The average occlusal wear per posterior tooth was 2.3 mm3, with 65.2% of teeth showing values greater than 1 mm3. Males, mandibular teeth, and first molars exhibited slightly greater wear levels than females (median, 2.57 and 2.21 mm3, respectively; p = 0.005), maxillary teeth, and first or second premolars, respectively. In all first premolars and in the mandibular second premolars, the buccal cusps were primarily affected with no other distinct patterns. There were weak to moderate correlations between tooth types, apart from certain strong correlations detected in males.

CONCLUSIONS

Posterior tooth wear was highly prevalent after a 13-year period starting at the onset of permanent dentition. The detected patterns are in accordance with the concept of canine guidance occlusion that is transforming into group synergy through function.

CLINICAL RELEVANCE

The widespread tooth wear occurrence and the high intra- and inter-individual variability underline the need for individual patient monitoring to identify high-risk patients at early stages.

Tooth wear and socioeconomic status in childhood and adulthood: Findings from a systematic review and meta-analysis of observational studies

OBJECTIVES

To evaluate the association and level of evidence between socioeconomic status (SES) and tooth wear (TW) in children, adolescents, and adults.

DATA

Eligibility criteria comprised population-based observational studies assessing the association between SES and TW in permanent dentition of adolescents and adults. Interventional and descriptive studies or those without an internal comparison between exposed and nonexposed groups were excluded. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were applied where applicable. Risk of bias (RoB) was assessed using the Newcastle-Ottawa scale. Meta-analyses were conducted to estimate the pooled effect measures. Q-statistic, I²statistic, subgroup and sensitivity analyses assessed study heterogeneity.

SOURCES

PubMed/Medline, Embase, Scopus, Web of Science, LILACS, SciELO, Cochrane Library, and Google Scholar databases were searched for articles published in English between 1st January 1980 and 31st March 2021.

RESULTS

Sixty-five studies were included, involving 63,893 participants in over 30 countries. A positive association was found between TW and education (OR=1.25 [0.96; 1.62]), family income (OR=1.18 [0.91; 1.53]), and private school (OR= 1.24 [0.90; 1.72]) among adolescents. Higher educated adults had a lower risk for TW (OR=0.70 [0.52; 0.93]). Most included studies had a moderate RoB. Limitations relating to population representation and assessment methodologies were identified in the included studies.

CONCLUSIONS

SES was associated with TW with its direction depending on the individuals' age. The overall quality of evidence was moderate.

CLINICAL SIGNIFICANC

SES should be included as part of the routine screening and risk assessment for tooth wear.

Longitudinal 3D Study of Anterior Tooth Wear from Adolescence to Adulthood in Modern Humans

Simple Summary

Tooth wear is the loss of tooth substance during everyday functioning by means other than dental caries. It is expected at a certain level in every person, and it increases with age. In the last decades, due to the increased life expectancy and high patient demands, it has become an important problem modern dentistry has to face. However, the average amount of tooth wear among individuals remains controversial. The purpose of this clinical study was to precisely detect the extent of anterior tooth wear over a thirteen-year period, from adolescence to adulthood. The present study revealed the very high tooth wear occurrence in the population already at early adulthood and showed that wear monitoring at an individual level is important for dentists to enable the better understanding of the problem and allow timely targeted interventions for patients in need. These might be preventive, such as the prescription of mouth guards to limit grinding and the cessation of harmful habits that lead to tooth wear, or interceptive, such as the restoration of the lost tooth substance to stop the progress of the condition and improve esthetics and function.

Abstract

In modern humans, tooth wear can easily be observed as a loss of tooth substance, but its precise measurement is problematic. The aim of this longitudinal cohort study was to determine the precise amount of occlusal tooth wear in the anterior permanent dentition from adolescence to adulthood. Corresponding tooth crowns from serial 3D digital dental models of 72 individuals were best fit-approximated by applying novel, highly accurate 3D superimposition methods. The superimposed crowns were simultaneously sliced on intact structures, and the differences in the volumes of the subsequent occlusal parts were calculated. Over a thirteen-year period, there was an average loss of anterior occlusal surfaces of 1.58 mm³ per tooth. Tooth surface loss in at least one tooth was higher than 1 mm³ in 93.1% of the human subjects. Tooth wear severity differed by sex and tooth type, with males showing higher values versus females and upper canines versus other anterior teeth. The study revealed the endemic occurrence of occlusal anterior tooth wear, highlighting the need for monitoring of the condition in the population to identify high-risk patients and enable timely interventions. The novel methods applied here on 3D digital models are recommended for this.

3D Occlusal Tooth Wear Assessment in Presence of Limited Changes in Non-Occlusal Surfaces

The study aimed to develop an accurate and convenient 3D occlusal tooth wear assessment technique, applicable when surfaces other than the occlusal undergo changes during the observation period. Various degrees of occlusal tooth wear were simulated in vitro on 18 molar and 18 premolar plaster teeth. Additionally, their buccal and lingual surfaces were gently grinded to induce superficial changes and digital dental models were generated. The grinded and the original tooth crowns were superimposed using six different 3D techniques (two reference areas with varying settings; gold standard: GS). Superimposition on intact structures provided the GS measurements. Tooth wear volume comprised the primary outcome measure. All techniques differed significantly to each other in their accuracy (p < 0.001). The technique of choice (CCD: complete crown with 30% estimated overlap of meshes) showed excellent agreement with the GS technique (median difference: 0.045, max: 0.219 mm³), no systematic error and sufficient reproducibility (max difference < 0.040 mm³). Tooth type, tooth alignment in the dental arches, and amount of tooth wear did not significantly affect the results of the CCD technique (p > 0.01). The suggested occlusal tooth wear assessment technique is straightforward and offers accurate outcomes when limited morphological changes occur on surfaces other than the occlusal.

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.

Operators matter - An assessment of the expectations, perceptions, and performance of dentists, postgraduate students, and dental prosthetist students using intraoral scanning

OBJECTIVE

to assess the expectations, perceptions and performance of different operators with varying backgrounds and training in the use of full-arch intraoral scanning (IOS).

METHODS AND MATERIALS

Dentists (DENT), postgraduate dental students (DPG), and student prosthetists (PROS) were invited to join an IOS training workshop. Participants completed a satisfactory scan of a mannikin-mounted typodont with the total scanning time (TST) recorded. They also completed anonymised pre and post-training questionnaires covering their background, and IOS expectations and experience. Statistical analysis was performed using the Mann-Whitney U, Kruskal Wallis, and chi-square tests. Open-ended questions were analysed manually and using Leximancer.

RESULTS

Twenty-seven participants were recruited: 10 DENT; 10 PROS; and 7 DPG. Positive expectations of IOS was reported by 93 % of participants. Combined TST was 285 ± 83 s, with the PROS TST significantly longer (p < 0.05, 337 ± 79 s). Further training need was reported by 60 % of PROS and 50 % of DENT versus 14 % of DPG. Positive IOS experience was reported by 96 % of participants, 74 % perceived it to be accurate, and 63 % found it easy to use. Eighty-five percent of all participants stated that cost would influence their decision of adopting IOS in their practice.

CONCLUSION

Expectations and perceptions of IOS were overwhelmingly positive, irrespective of operator background and experience. Scanning performance and training needs depended on the operator's background. Cost of IOS remains a barrier to acquiring the technology.

CLINICAL SIGNIFICANCE

IOS training must be customised to accommodate the needs of different operators. The cost of IOS needs revision to improve its accessibility.

Influence of Scanner Precision and Analysis Software in Quantifying Three-Dimensional Intraoral Changes: Two-Factor Factorial Experimental Design

BACKGROUND

Three-dimensional scans are increasingly used to quantify biological topographical changes and clinical health outcomes. Traditionally, the use of 3D scans has been limited to specialized centers owing to the high cost of the scanning equipment and the necessity for complex analysis software. Technological advances have made cheaper, more accessible methods of data capture and analysis available in the field of dentistry, potentially facilitating a primary care system to quantify disease progression. However, this system has yet to be compared with previous high-precision methods in university hospital settings.

OBJECTIVE

The aim of this study was to compare a dental primary care method of data capture (intraoral scanner) with a precision hospital-based method (laser profilometer) in addition to comparing open source and commercial software available for data analysis.

METHODS

Longitudinal dental wear data from 30 patients were analyzed using a two-factor factorial experimental design. Bimaxillary intraoral digital scans (TrueDefinition, 3M, UK) and conventional silicone impressions, poured in type-4 dental stone, were made at both baseline and follow-up appointments (mean 36 months, SD 10.9). Stone models were scanned using precision laser profilometry (Taicaan, Southampton, UK). Three-dimensional changes in both forms of digital scans of the first molars (n=76) were quantitatively analyzed using the engineering software Geomagic Control (3D Systems, Germany) and freeware WearCompare (Leeds Digital Dentistry, UK). Volume change (mm³) was the primary measurement outcome. The maximum point loss (μm) and the average profile loss (μm) were also recorded. Data were paired and skewed, and were therefore compared using Wilcoxon signed-rank tests with Bonferroni correction.

RESULTS

The median (IQR) volume change for Geomagic using profilometry and using the intraoral scan was -0.37 mm³ (-3.75-2.30) and +0.51 mm³ (-2.17-4.26), respectively (P<.001). Using WearCompare, the median (IQR) volume change for profilometry and intraoral scanning was -1.21 mm³ (-3.48-0.56) and -0.39 mm³ (-3.96-2.76), respectively (P=.04). WearCompare detected significantly greater volume loss than Geomagic regardless of scanner type. No differences were observed between groups with respect to the maximum point loss or average profile loss.

CONCLUSIONS

As expected, the method of data capture, software used, and measurement metric all significantly influenced the measurement outcome. However, when appropriate analysis was used, the primary care system was able to quantify the degree of change and can be recommended depending on the accuracy needed to diagnose a condition. Lower-resolution scanners may underestimate complex changes when measuring at the micron level.