J Periodontal Implant Sci.  2018 Apr;48(2):124-134. 10.5051/jpis.2018.48.2.124.

Methods for quantitative measurement of tooth wear using the area and volume of virtual model cusps

• Kim SH
• Park YS
• Kim MK
• Kim S
• Lee SP

• KMID: 2410691
• DOI: http://doi.org/10.5051/jpis.2018.48.2.124

Abstract

PURPOSE
Clinicians must examine tooth wear to make a proper diagnosis. However, qualitative methods of measuring tooth wear have many disadvantages. Therefore, this study aimed to develop and evaluate quantitative parameters using the cusp area and volume of virtual dental models.
METHODS
The subjects of this study were the same virtual models that were used in our former study. The same age group classification and new tooth wear index (NTWI) scoring system were also reused. A virtual occlusal plane was generated with the highest cusp points and lowered vertically from 0.2 to 0.8 mm to create offset planes. The area and volume of each cusp was then measured and added together. In addition to the former analysis, the differential features of each cusp were analyzed.
RESULTS
The scores of the new parameters differentiated the age and NTWI groups better than those analyzed in the former study. The Spearman ρ coefficients between the total area and the area of each cusp also showed higher scores at the levels of 0.6 mm (0.6A) and 0.8A. The mesiolingual cusp (MLC) showed a statistically significant difference (P < 0.01) from the other cusps in the paired t-test. Additionally, the MLC exhibited the highest percentage of change at 0.6A in some age and NTWI groups. Regarding the age groups, the MLC showed the highest score in groups 1 and 2. For the NTWI groups, the MLC was not significantly different in groups 3 and 4. These results support the proposal that the lingual cusp exhibits rapid wear because it serves as a functional cusp.
CONCLUSIONS
Although this study has limitations due to its cross-sectional nature, it suggests better quantitative parameters and analytical tools for the characteristics of cusp wear.

Keyword

Dental occlusion; Indexes; Statistical models; Tooth wear

MeSH Terms

Classification
Dental Models
Dental Occlusion
Diagnosis
Humans
Methods*
Models, Statistical
Tooth Wear*
Tooth*

Figure

• 

  Figure 1 Reference points and virtual occlusal plane. (A) a: MBCP, b: DBCP, c: MLCP. (B) Virtual occlusal plane. (C) Offset planes at 0.2 mm intervals.MBCP: mesiobuccal cusp point, DBCP: distobuccal cusp point, MLCP: mesiolingual cusp point.

• 

  Figure 2 (A) Offset plane at 0.6 mm. (B) Sectioned area, 0.6A. (C) Sectioned volume, 0.6V.

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