Is predicting masticatory function based on mandibular bone atrophy as defined by clinical and radiographic parameters possible? A clinical study.

STATEMENT OF PROBLEM

The degree of mandibular bone atrophy can guide and determine the choice of prosthetic treatment. Although several methodologies have been proposed for classifying atrophy, the clinical and radiographic parameters considered for the classification of mandibular bone atrophy should be standardized.

PURPOSE

The purpose of this clinical study was to evaluate the influence of methodologies of mandibular bone atrophy categorization on the masticatory function in complete denture (CD) wearers and to verify the relationship between these parameters according to the retention and stability of the mandibular CD.

MATERIAL AND METHODS

CD wearers were radiographically and clinically evaluated to determine the mandibular bone atrophy levels. Three classifications were adopted: the Cawood and Howell criteria, the Wical and Swoope criteria, and the Kapur classification. CD retention and stability were scored based on the Sato et al method. The masticatory function was evaluated by the multiple sieve method using optical test food to determine the masticatory performance (MP) indexes (median particle size, MP X50; homogeneity index, MP B) and the masticatory efficiency (sieves 4 and 2.8).

RESULTS

In this sample of 63 individuals (mean age of 67.4 years), atrophic participants presented significant differences in all radiographic parameters (Mann-Whitney test, P<.05) with both the Cawood and Howell and Wical and Swoope methodologies. No differences in masticatory function were found, except for atrophic participants classified by Wical and Swoope criteria, who had worse MP X50 (P=.047) than nonatrophic participants, with a medium effect size of 0.7. The retention of the mandibular CD significantly affected the masticatory outcomes, with higher values for MP X50 (P=.012) and MP B (P=.040) and lower values for masticatory efficiency, 2.8 (P=.008) for atrophic participants. The presence of mandibular bone atrophy showed an association with poor retention (P=.04) and poor stability (P=.002) when the Cawood and Howell criteria were adopted (Fisher exact test, P<.05).

CONCLUSIONS

The Kapur classification confirmed the clinical condition of the participants' atrophy, and the most clinically atrophic participants showed poor retention and stability of the mandibular CD. Only the poor retention directly affected the masticatory function. Radiographic evaluations alone did not provide sufficient data to determine the predictability of CD treatment regarding the participants' masticatory function. Radiographically, atrophic participants with poor retention had impaired mastication.