Abstract

The aim of this investigation was to characterize peri-implant tissue breakdown following ligature-induced plaque accumulation around osseointegrated implants in the rhesus monkey. Two hydroxyapatite-coated cylindrical implants were inserted bilaterally in the second premolar and first molar region of both mandible and maxilla in four non-human primates (Macaca mulatto). The implants were left submerged to osseointegrate for one year. Eight weeks after healing abutment connection, a two-month plaque control program was initiated. At the end of this period, clinical and radiographic recordings were carried out, and peri-implant subgingival microbial samples were obtained (baseline). Subsequently, cotton ligatures were placed around the healing abutments and all plaque control procedures were abandoned. Clinical and radiographic recordings were repeated at five and ten months post baseline. Microbial samples were again obtained at ten months post baseline. The defect induction period was then terminated by removing the ligatures. Four weeks thereafter, clinical, radiographic and microbial examinations were repeated. Mean Plaque Index (PlI), Gingival Index (GI), and bleeding on probing (BOP) scores increased over the plaque accumulation period (p < 0.01). The PlI, and GI scores decreased after ligature removal (P < 0.001). Mean probing depth (PD) and probing attachment levels (PAL) increased significantly between baseline and the five- and ten-months examinations (ΔPD 3.0mm, ΔPAL 2.7 mm; P < 0.05). PD values were somewhat reduced following ligature removal, however, PAL values remained unaltered. Except for one, the 32 implants remained immobile during the entire study period with no significant difference between mean Periotest values at baseline and at follow-up examinations. The peri-implant subgingival microflora at baseline was dominated by coccoid cells. Following ligature placement, the microflora included a large proportion of Gram-negative anaerobic rods, predominantly Porphyromonas gingivalis, Bacteroides forsythus, beta hemolytic Streptococcus, and Fusobacterium species. After ligature removal, the microflora largely remained unaltered. This study indicates that ligature-induced plaque accumulation around osseointegrated implants promotes development of progressive peri-implant tissue breakdown in non-human primates. This defect model may be useful to study modalities to arrest peri-implant osteitis lesions and to treat peri-implant osteitis defects.

LLU Discipline

Implant Dentistry

Department

Implant Dentistry

School

Graduate School

First Advisor

Ulf M.E. Wikesjö

Second Advisor

Jaime L. Lozada

Third Advisor

Grenith Zimmerman

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1995

Date (Title Page)

6-1995

Language

English

Library of Congress/MESH Subject Headings

Dental Implants; Macaca mulatta

Type

Thesis

Page Count

2; vii; 35

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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