Periodontal healing following experimental injury to root surfaces of human teeth

Long term clinical result of implant induced injury on the adjacent tooth

The purpose of the retrospective study was to investigate the long-term result of implant-induced injury on the adjacent tooth. The subjects of this retrospective study were patients who had received implants and had tooth injury; direct invasion of root (group I), root surface contact (group II), or < 1 mm distance of the implant from the root (group III). Clinical and pathological changes were periodically examined using radiographs and intra-oral examinations. Paired t-tests and chi-square tests were used to evaluate the implant stability quotient (ISQ) of implant and tooth complications, respectively (α = 0.05). A total of 32 implants and teeth in 28 patients were observed for average 122.7 (± 31.7, minimum 86) months. Seven teeth, three of which were subsequently extracted, needed root canal treatment. Finally, 90.6% of the injured teeth remained functional. Complications were significant and varied according to the group, with group I showing higher events than the others. The ISQs increased significantly. One implant in group I resulted in osseointegration failure. The implant survival rate was 96.9%. In conclusion, it was found even when a tooth is injured by an implant, immediate extraction is unnecessary, and the osseointegration of the invading implant is also predictable.

Healing of root and surrounding periodontium after root damage with miniscrew implants: a histomorphologic study in dogs

OBJECTIVES

The main purpose of this study was to investigate the detailed healing process of the roots and surrounding periodontium [cementum, periodontal ligament (PDL), and bone] at different time points after intentional root damage with miniscrew implants (MSIs).

MATERIALS AND METHODS

After cone-beam computed tomography examination and measurement, a total of 78 premolar and molar roots from five beagle dogs were intentionally damaged by implanting miniscrews in the interradicular region. MSIs were immediately removed, and the histological morphology was observed at days 0 and 3 and at weeks 1, 2, 3, 4, 6, 8, and 12 after root injury using haematoxylin and eosin and fluorescence stainings (fluorescence staining was performed at days 28 and 56).

RESULTS

An early new attachment of PDL adhering on to the damaged root surface was found at week 2 after root injury. Tissue differentiation of newly formed bone tissue, PDL, and cementum began at week 3. Moreover, the newly formed cementum and bone were constantly forming and mineralising at weeks 4, 6, 8, and 12, and the width of PDL gradually narrowed until close to the normal width at week 12.

CONCLUSIONS

This study demonstrated the complete healing process of the roots and surrounding periodontium after root damage with MSIs in dogs when the damage was limited to the cementum or dentin.

CLINICAL RELEVANCE

The findings of this study may help provide a better understanding of the detailed healing process in roots and PDLs damaged by MSIs.