Long-Term Bone Changes at Edentulous Sites

BACKGROUND: Tooth loss is a debilitating occurrence that may affect the patient’s emotional and mental well-being. Delays in necessary restorative treatment may occur dependent on the patient’s finances or other elaborate dental treatment plans. Prosthetically guided implants have become the standard of care regarding definitive treatment, however there is a lack of evidence discussing the stability of edentulous sites if deferment of treatment is required. OBJECTIVE: The aim of this study is to measure long-term changes of the edentulous alveolar ridge (height and width) and anatomical structures (e.g. sinus floor, inferior alveolar canal). METHODS: Charts of patients with at least two Cone Beam Computed Tomographies (CBCTs) taken 12 months apart within a 10-year period were reviewed. If included, the CBCTs were anonymized and imported into the Dolphin Imaging Premium Software, were superimposed, and linear measurements of height and width (3mm and 5mm from alveolar crest) and change in sinus floor location were calculated. The landmarks used were the anterior and posterior nasal spines for maxilla and the superior border of the mental foramina (mandible). RESULTS: Eighty-three patients (age at first CBCT: 62.5±0.7 years; 44 females) contributed to the study with 253 sites (148 molar, 55 premolar, 14 canine, 36 anterior) in CBCTs recorded 26.3±1 months apart. Alveolar bone height changes were 0.49±0.05mm (coronal; p< 0.0001) and 0.42±0.05mm (sagittal; p< 0.0001). The difference between the mandible and maxilla was significant (coronal; p< 0.0001) and sagittal; p< 0.0001). Width changes were 0.31±0.04mm (3mm; p< 0.0001) and 0.24±0.03mm (5mm; p< 0.0001), respectively. The difference between the maxillary and mandibular arch was not significant (3mm; p=0.21 and 5mm; p=0.94). Sinus floor location minimally changed by 0.2±0.02mm (coronal; p=0.51) and -0.02±0.04mm (sagittal; p=0.58). CONCLUSION: Alveolar bone height and width of established edentulous sites undergo minimal changes for at least a 2-year period. Although mandibular site height changes are statistically significantly greater than in maxillary sites, the differences are clinically insignificant.