ABSTRACT
OBJECTIVES: This study aims to determine if there are enough buccal alveolar bone thickness to perform an immediate dental implant placement in anterior and posterior maxillary teeth. MATERIAL AND METHODS: A total of 1463 teeth were examined, from 202 cone-beam computed tomography scans with voxel sizes of 0.15 mm. On each tooth, the following measures were determined: the alveolar bone thickness in two locations; the vertical distance between the buccal alveolar crest and cementoenamel junction; the angle between the tooth's long axis and the alveolar bone axial inclination in the sagittal plane. RESULTS: In the most coronal location of maxillary teeth, the thickness of alveolar bone was lower than 0.6 (SD 0.6) mm in 50% of the teeth, and in the middle of the root the bone thickness was, on average, 0.96 (SD 0.6) mm. For the same maxillary teeth, the vertical distance between the buccal alveolar crest and cementoenamel junction and the angulation measured were, on average, 3.6 (SD 1.2) mm and 12.1º (SD 1.4º), respectively. CONCLUSIONS: The present study revealed that in most cases the thickness of buccal alveolar bone was less than 1 mm. Consequently, in such cases, immediate dental implant placement operation is not recommended, or should be combined with bone regeneration techniques.
ABSTRACT
AIM: To evaluate the primary and secondary stability of implants in the posterior maxilla. METHODS: Patients were allocated into three groups: (A) native bone, (B) partially regenerated bone, and (C) nearly totally regenerated bone. Insertion torque (IT) and implant stability quotient (ISQ) were measured at placement, to evaluate whether satisfactory high primary stability (IT ≥ 45 N/cm; ISQ ≥ 60) was achieved; ISQ was measured 15, 30, 45, and 60 days after placement, to investigate the evolution to secondary stability. RESULTS: 133 implants (Anyridge®, Megagen) were installed in 59 patients: 55 fixtures were placed in Group A, 57 in Group B, and 21 in Group C. Fifty-two implants had satisfactory high primary stability (IT ≥ 45 N/cm; ISQ ≥ 60). A positive correlation was found between all variables (IT, ISQ at t = 0, t = 60), and statistically higher IT and ISQ values were found for implants with satisfactory high primary stability. Significant differences were found for IT and ISQ between the groups (A, B, and C); however, no drops were reported in the median ISQ values during the healing period. CONCLUSIONS: The evaluation of the primary and secondary implant stability may contribute to higher implant survival/success rates in critical areas, such as the regenerated posterior maxilla. The present study is registered in the ISRCTN registry with ID ISRCTN33469250.
