(1) if pathologic pulp tissue alterations can be induced in the teeth of monkeys subjected to experimental breakdown of the periodontal tissues and
(2) if inflammatory reactions are initiated in the
pulp of teeth subjected to root planing and subsequent plaque accumulation on the exposed root dentin surfaces
Materials and Methods:
– n: 6 cynomolgus monkeys with 114 teeth. All of the subjects had generalized gingivitis and moderate plaque accumulation teeth were divided to 5 gps as shown in Table.1.
– High Carb diet was implemented to form a gross plaque accumulation and marginal periodontitis within 5-7 months.
-Periodontal tissue breakdown was produced by placing orthodontic elastics around the neck of teeth then after 2 months it was replaced by floss. After 3 months of floss ligature floss could pass the furcation areas of involved teeth. Floss ligature was kept until 30-40% of bone loss occurred.
-In 1 gp of teeth the ligature was removed without tx. The remaining teeth received Scaling & root planing from CEJ to the marginal bone. Plaque was allowed to accumulated for 2, 10, and 30 days post surgically and the pulp of involved teeth was harvested.
-Animals were sacrificed, teeth were radiographed B-L and M-D, demineralized, sectioned, and stained with H&E.
-Histological examination of 2ndry dentine and inflammatory infiltrates at the site of exposed dentine and the coronal portion of the pulp above the furcation.
Most highlighted results:
-Teeth with ligature showed gingivitis with deep PD, bone loss, increased mobility and drifting.
-CEJ-MBL distance was longer in anterior teeth than posterior teeth.
-Normal bone height. Irregular secondary dentin was noted in half of the cases in the coronal pulp and inflammatory cells around the 2ndry dentin was observed in 1/4 of the cases.
-Most of teeth with periodontitis exhibited mild pathologic changes in the pulp tissue of the root canals (2ndry dentin)
-Teeth with periodontitis also frequently exhibited evidence of external root resorption. Shallow defects of the root surface were found in most of the examined teeth
-2ndry dentin formations and inflammatory cell infiltrates occurred with the same frequency as in roots with periodontitis alone and roots after scaling and root planing as shown in Table.2..
-No significant differences in the intensity and incidence of pulp changes among teeth exposed to the different periods (2, 10 and 30 days) of plaque accumulation as shown in Table.1.
The process of destructive periodontitis is not always accompanied by pathological alterations within the pulp tissue of the affected teeth and the pathological alteration recorded was the formation of 2ndry dentine.