Evaluation of the effect of duration of edentulousness on the position of neutral zone in relation to residual alveolar ridge using Computed Tomography (CT)  An Invivo Study

Cholan Ramanujam; Sabarigirinathan C; Anand B

Volume : VI, Issue : VI, June - 2017

Evaluation of the effect of duration of edentulousness on the position of neutral zone in relation to residual alveolar ridge using Computed Tomography (CT) An Invivo Study

Cholan Ramanujam, Sabarigirinathan C, Anand B

Abstract :

Purpose: To evaluate the effect of duration of edentulousness on the position of neutral zone in relation to the crest of the residual alveolar ridge in the molar, premolar and anterior region in mandibular complete denture using Computed Tomography (CT). Materials and Method: Thirty edentulous patients were categorized into three groups based on their period of edentulousness– Group 1: 0 to 6 months of edentulousness, Group 2: 7 months to 2 years of edentulousness and Group 3: 3 years to 10 years of edentulousness. The neutral zone position in relation to the crest of the alveolar ridge was evaluated by adapting TMA wires on the center of the compound rim and on the ridge crest on the master cast. CT images of the casts and the rims were obtained and the results were compared in the right and left premolar, molar and anterior region. When the images of the rims and cast coincided, a zero score was assigned and buccal or labial locations of the neutral zone with respect to the ridge are given a positive value. Lingual locations of the neutral zone with respect to the ridge were given a negative value. The results were statistically analyzed using one way ANOVA followed by Tukey�s Post Hoc test. Results: In the premolar and molar regions, neutral zone was positioned lingual to the crest in group 1 patients and there was a gradual shift to the buccal side in group 2 and 3 patients. Highly statistical significant difference was found between group 1 and 3 in the left premolar and molar region (p=.000). No statistical significant difference was seen between the groups in the anterior region. Conclusion: It was concluded that the neutral zone was found to be located lingual to crest of the ridge during the early period of edentulousness i.e., between 0–6 months. After that it starts shifting buccally and labially in relation to the crest. This shifting of neutral zone is more pronounced after 3 years of extraction.