Original Article
Masticatory performance and areas of occlusal contact and near contact in subjects with normal occlusion and malocclusion*,**,,★★

https://doi.org/10.1067/mod.2002.122829Get rights and content

Abstract

This preliminary study evaluated relationships between masticatory performance and areas of interocclusal distance contact (<50 μm) and near contact (50-350 μm) of the buccal segments during maximum intercuspation. The sample included subjects with normal occlusion (n = 18) and Class I (n = 14), Class II (n = 13), and Class III (n = 6) malocclusions. Chewing performance was evaluated on the basis of the breakdown of CutterSil (Heraeus Kulze, South Bend, Ind); chewing ability was assessed by the number of chews necessary to swallow jerky and almonds. Impressions of the buccal segments, taken with Blu Mousse (Parkell Bio-Materials, Farmingdale, NY) impression material, were scanned and enlarged, and each subject's first molars and premolars were manually traced bilaterally to estimate the platform area. The areas of contact and near contact (ACNC) that measured between 0 and 350 μm thick were estimated optically on the basis of the amount of light transmitted through the impression. The results showed no significant differences in platform area between the right and left sides or between the malocclusion groups. ACNC were negatively related to median particle size and broadness of particle distribution. There were no correlations between ACNC and the number of chews necessary to swallow jerky or almonds. Subjects with normal occlusion had significantly larger ACNC than those with Class I, Class II, and Class III malocclusions, in descending order. Subjects with Class III malocclusions had the smallest areas of near contact (<350 μm). We concluded that ACNC are similar on the right and left sides; that subjects with larger ACNC are better able to break down foods; and that subjects with malocclusions have smaller ACNC than those with normal occlusions. (Am J Orthod Dentofacial Orthop 2002;121:602-9)

Section snippets

Material and methods

The sample comprised 51 untreated subjects, 18 with normal occlusion (6 males, 12 females) and 33 with malocclusion. The normal subjects were selected from students and staff at Baylor College of Dentistry in Dallas and their children. The malocclusion subsample included 14 Class I subjects (6 males, 8 females), 13 Class II subjects (5 males, 8 females) and 6 Class III subjects (2 males, 4 females). They were orthodontic patients admitted consecutively for treatment and screening at Baylor

Results

The first molars, second premolars, and first premolars had a PA of 179.8 ± 21.5 mm2 on the right side and 177.6 ± 18.4 mm2 on the left side. The differences between right and left PAs were not statistically significant. PAs of the right and left sides were significantly but only moderately correlated R = 0.62; P <.001). PAs were not significantly different between males and females, and they were not significantly correlated with chronologic age. Right and left PAs also showed no statistically

Discussion

Previous reports of ACNC are difficult to compare because the few studies have used different procedures and methods. We showed relatively small (2 mm2) areas of contact below 50 μm on the left and right sides. These areas are considerably smaller than the 25 mm2 estimated for adults by Yurkstas and Manly.6 However, comparisons are confounded because they used warm black wax for occlusal registrations and maximum biting forces, which would have increased ACNC.17, 18 Yurkstas and Manly6 also

Conclusions

There were no significant differences in ACNC between right and left sides, indicating no side differences in how well the premolars and first molar fit together. Contact areas (thickness <50 μm) covered approximately 2 mm2 (interquartile range, 1-4 mm2); contact and near-contact areas less than 350 μm thick covered approximately 37.5 mm2 (interquartile range, 25-45.5 mm2). ACNC showed weak-to-moderate correlations with median particle size and broadness of the particle distribution, suggesting

References (24)

  • RS Manly et al.

    Masticatory function of children with malocclusion

    J Dent Res

    (1951)
  • FR Shiere et al.

    The effect of the changing dentition on masticatory function

    J Dent Res

    (1952)
  • Cited by (142)

    View all citing articles on Scopus
    *

    bSouthwest Medical University, Dallas.

    **

    cUniversity of Texas Health Science Center, Houston.

    Research was partially supported by an AAO Foundation Center Grant and NIH-NIDCR training grant DE07188.

    ★★

    Reprint requests to: Dr Peter H. Buschang, Department of Orthodontics, Baylor College of Dentistry, The Texas A & M University System Health Science Center, 3302 Gaston Ave, Dallas, TX 75246; e-mail, [email protected].

    View full text