Equicrestal and subcrestal dental implants: a histologic and histomorphometric evaluation of nine retrieved human implants.
BACKGROUND
Stability of peri-implant crestal bone plays a relevant role relative to the presence or absence of interdental papilla. Several factors can contribute to the crestal bone resorption observed around two-piece implants, such as the presence of a microgap at the level of the implant-abutment junction, the type of connection between implant and prosthetic components, the implant positioning relative to the alveolar crest, and the interimplant distance. Subcrestal positioning of dental implants has been proposed to decrease the risk of exposure of the metal of the top of the implant or of the abutment margin, and to get enough space in a vertical dimension to create a harmoniously esthetic emergence profile.


METHODS
The present retrospective histologic study was performed to evaluate dental implants retrieved from human jaws that had been inserted in an equicrestal or subcrestal position. A total of nine implants were evaluated: five of these had been inserted in an equicrestal position, whereas the other four had been positioned subcrestally (1 to 3 mm).


RESULTS
In all subcrestally placed implants, preexisting and newly formed bone was found over the implant shoulder. In the equicrestal implants, crestal bone resorption (0.5 to 1.5 mm) was present around all implants.


CONCLUSIONS
The subcrestal position of the implants resulted in bone located above the implant shoulder.
Dental School, University of Chieti-Pescara, Chieti, Italy.
Marco
M
Degidi
Vittoria
V
Perrotti
Jamil A
JA
Shibli
Arthur B
AB
Novaes
Adriano
A
Piattelli
Giovanna
G
Iezzi
D000134:Acid Etching, Dental; D016301:Alveolar Bone Loss / Q000473:pathology; D000539:Alveolar Process / Q000473:pathology*; D001857:Bone Matrix / Q000473:pathology; D016723:Bone Remodeling / Q000502:physiology; D003238:Connective Tissue / Q000473:pathology; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D016591:Histocytological Preparation Techniques; D006801:Humans; D007091:Image Processing, Computer-Assisted; D057893:Immediate Dental Implant Loading; D016348:Osseointegration / Q000502:physiology; D010006:Osteoblasts / Q000473:pathology; D010011:Osteocytes / Q000473:pathology; D010012:Osteogenesis / Q000502:physiology; D012189:Retrospective Studies; D013499:Surface Properties
D015921:Dental Implants