INTRODUCTION: Tooth extraction is followed by marked osseous changes of the residual alveolar ridge including severe bone alterations both in height and in width. However, such remodelling could jeopardize the subsequent implant insertion for two main reasons. Firstly, the absence of adequate bone levels makes implant placement impossible; secondly, aesthetic problems in the fabrication of implanto-supported restoration could be caused by serious bone re-absorption. Thus, it is of crucial importance that the dental surgeon knows how the alveolar crest changes when a single tooth has been removed. The aim of this study was to evaluate the pattern of alveolar crest remodelling observed in a single intercalated area of tooth extraction after at least a period of 6 months of healing, using standardized photos of model casts. MATERIAL AND METHODS: Among the patients who were treated for a single intercalated tooth extraction during the last 2 years at the department of dentistry at Versilia Hospital, Lido di Camaiore (Lucca), Italy, we selected 50 patients. The amount of alveolar crest remodelling was assessed on standardized photos of study models. All measurement were recorded on an Excel sheet (Excel, Windows XP((R))) and each value was multiplied by the enlargement index so that true values of re-absorption could be obtained. Finally, we have calculated the percentage of amount of alveolar crest remodelling and shifting of alveolar crest. RESULTS: We calculated the percentage of buccal remodelling and alveolar crest shift. The buccal re-absorption was 19.4 +/- 9.4% at mesial point, 39.1 +/- 10.4% at midpoint and 20.3 +/- 10.7% at distal level. Moreover, the shift of the alveolar crest was 59.1 +/- 11.2% at mesial point, 64.8 +/- 10.5% at the midpoint and 56 +/- 12.5% at distal point. CONCLUSIONS: This study confirmed that buccal wall tends to re-absorb after the extraction according to a specific pattern. Thus, the re-absorption at the midpoint represent the double of bone loss at the distal and the mesial points. Furthermore, we have observed first how the alveolar crest shifts placing along the more lingual/palatal line which divides the original alveolar crest into three parts.
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