Aim: To identify factors that may influence ridge alterations occurring at the buccal aspect of the extraction site following immediate implant placement.
Material and methods: In 93 subjects, single-tooth implants were placed immediately into extraction sockets in the maxilla (tooth locations 15-25). A series of measurements describing the extraction site were made immediately after implant installation and at re-entry, 16 weeks later. The implant sites were stratified according to four factors: (i) implant location (anterior/posterior), (ii) cause of tooth extraction (periodontitis/non-periodontitis), (iii) thickness of the buccal bone walls (< or = 1 or > 1 mm) and (iv) the dimension of the horizontal buccal gap (< or = 1 or > 1 mm).
Results: (i) The location where the implant was placed (anterior/posterior) as well as (ii) the thickness of the buccal bone crest and (iii) the size of the horizontal buccal gap significantly influenced the amount of hard tissue alteration that occurred during a 4-month period of healing. At implant sites in the premolar segment, the fill of the horizontal gap was more pronounced than in the incisor-canine segment, while the vertical crest reduction was significantly smaller. Furthermore, at sites where the buccal bone wall was thick (>1 mm) and where the horizontal gap was large (>1 mm), the degree of gap fill was substantial.
Conclusions: The thickness of the buccal bone wall as well as the dimension of the horizontal gap influenced the hard tissue alterations that occur following immediate implant placement into extraction sockets.