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
Digital Publisher
Loma Linda University Libraries
Copyright
Author
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.
Recommended Citation
Hanisch, Oliver, "Experimental Peri-Implant Tissue Breakdown in Rhesus Monkeys" (1995). Loma Linda University Electronic Theses, Dissertations & Projects. 2367.
https://scholarsrepository.llu.edu/etd/2367
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
Included in
Animal Experimentation and Research Commons, Bacteria Commons, Other Dentistry Commons, Periodontics and Periodontology Commons