Bone remodelling after regenerative procedures around implants placed in fresh extraction sockets: an experimental study in Beagle dogs.
BACKGROUND
After a tooth extraction, the height of the buccal wall tends to decrease. The literature indicates that regenerative techniques (guided bone regenerative [GBR] techniques) have succeeded in improving the bone levels. Therefore, this experiment set out to compare the physiological bone remodelling in Beagle dog models after implant placement in a fresh extraction socket, with and without the application of regenerative procedure.


METHODS
Five dogs were used in this study. Test and control sites were randomly selected. The experimental teeth (fourth pre-molar and first molar) were hemi-sected removing the distal roots and placing implants. Porcine bone was placed to fill the gap around the implant on the test sites and a reabsorbable membrane was used to cover the area. The dogs were put down at different times (2 weeks, 1 month and 3 months). The measurements were taken immediately and at 2, 4, 12 weeks after implant placement. Student's test for paired data was used to compare the means of the clinical measurements.


RESULTS
At 2 weeks: On the control sites, few signs of resorption were detected at the first molar only, while at the test sites bone levels were placed at the implant shoulder or above. At 4 weeks: On the control site, slight bone remodelling was observed, while on the test site minor signs of resorption or an increase of bone levels were detected. At 12 weeks: The alveolar crest on the control sites showed various degrees of remodelling. On the test sites stable bone levels or an increase of bone crest was observed.


CONCLUSIONS
With the limits of this study, the findings showed that GBR techniques were able to limit resorption of the alveolar crest after tooth extraction. A pattern of bone remodelling after tooth extraction and implant placement was observed in the control sites (no GBR) as well as in test sites (GBR), and although the exact cause of this is unclear, surgical trauma could play a role. Further studies are necessary to confirm these results and to clarify the precise causes of bone remodelling in fresh extraction sockets.
Istituto Stomatologico Tirreno, Versilia Hospital, Lido di Camaiore (LU), ItalyDepartment Oral Pathology, University of Genova, Genova, ItalyNanoworld Institute, University of Genova, Genova, ItalyDepartment of Implantology, University of Murcia, Murcia, SpainDepartment of Surgery, University of Pisa, Pisa, Italy.
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Istituto Stomatologico Tirreno, Versilia Hospital, Lido di Camaiore (LU), ItalyDepartment Oral Pathology, University of Genova, Genova, ItalyNanoworld Institute, University of Genova, Genova, ItalyDepartment of Implantology, University of Murcia, Murcia, SpainDepartment of Surgery, University of Pisa, Pisa, Italy.
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Ricci
Istituto Stomatologico Tirreno, Versilia Hospital, Lido di Camaiore (LU), ItalyDepartment Oral Pathology, University of Genova, Genova, ItalyNanoworld Institute, University of Genova, Genova, ItalyDepartment of Implantology, University of Murcia, Murcia, SpainDepartment of Surgery, University of Pisa, Pisa, Italy.
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Calvo-Guirado
Istituto Stomatologico Tirreno, Versilia Hospital, Lido di Camaiore (LU), ItalyDepartment Oral Pathology, University of Genova, Genova, ItalyNanoworld Institute, University of Genova, Genova, ItalyDepartment of Implantology, University of Murcia, Murcia, SpainDepartment of Surgery, University of Pisa, Pisa, Italy.
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Covani
D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D004285:Dogs; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D013524:Surgical Flaps; D013552:Swine; D013997:Time Factors; D014081:Tooth Extraction; D020390:Tooth Socket / Q000601:surgery*; D014945:Wound Healing / Q000502:physiology
D015921:Dental Implants