AIM: To assess the effect of conventional bracket slot vertical position (4 mm from incisal edge) on crown spatial orientation relative to adjacent and opposing teeth through proximal contact balance and occlusal contacts assessment. MATERIAL AND METHODS: Forty patients were divided into two groups; in the first group, brackets were bonded 4 mm from the intact incisal edge; in the second group, bracket position was determined individually by transferring the maximum embrasure difference to the bracket slot height difference. The difference of proximal contacts between premolars and molars was measured. Bite registration with the use of articulating paper was also performed on all patients. Traces indicating contact between premolar maxillary lingual cusps and opposing mandibular fossa of the first and second premolars were evaluated. Differences with respect to the distribution of unbalanced proximal contacts and negative contacts between the two bonding schemes were analyzed with the chi-square test at P = .05 level of significance. RESULTS: Aligning the bracket slot with the center of the clinical crown (FA point) consistently produced unbalanced proximal contacts in excess of 1 mm, as well as increased absence of occlusal contacts. CONCLUSION: Positioning the bracket slot on the center of the premolar crown may result in marginal ridge discrepancy between the premolars and molars and lack of occlusal contacts with opposing dentition. This may be due to the height difference noted between the buccal and lingual cusp of the premolars, as well as variation in molar tube or band placement. Functional occlusal analysis should be integrated in the finishing stages of treatment to facilitate proper premolar crown position.
AIM: To assess the effect of conventional bracket slot vertical position (4 mm from incisal edge) on crown spatial orientation relative to adjacent and opposing teeth through proximal contact balance and occlusal contacts assessment. MATERIAL AND METHODS: Forty patients were divided into two groups; in the first group, brackets were bonded 4 mm from the intact incisal edge; in the second group, bracket position was determined individually by transferring the maximum embrasure difference to the bracket slot height difference. The difference of proximal contacts between premolars and molars was measured. Bite registration with the use of articulating paper was also performed on all patients. Traces indicating contact between premolar maxillary lingual cusps and opposing mandibular fossa of the first and second premolars were evaluated. Differences with respect to the distribution of unbalanced proximal contacts and negative contacts between the two bonding schemes were analyzed with the chi-square test at P = .05 level of significance. RESULTS: Aligning the bracket slot with the center of the clinical crown (FA point) consistently produced unbalanced proximal contacts in excess of 1 mm, as well as increased absence of occlusal contacts. CONCLUSION: Positioning the bracket slot on the center of the premolar crown may result in marginal ridge discrepancy between the premolars and molars and lack of occlusal contacts with opposing dentition. This may be due to the height difference noted between the buccal and lingual cusp of the premolars, as well as variation in molar tube or band placement. Functional occlusal analysis should be integrated in the finishing stages of treatment to facilitate proper premolar crown position.