PubMed · 6959971
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B Keough. 1982. Root resection.. https://pubmed.ncbi.nlm.nih.gov/6959971/
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The aim of the present investigation was to analyze the periodontal tissues at immobilized teeth connected to osseointegrated implants. 10, 1-year old beagle dogs, were used. Bilaterally, the mandibular 2nd (2P2) and 3rd premolars (3P3) and 1st molars (1M1) were extracted. 2 titanium fixtures were installed in the edentulous segment of the right side of the mandible, one about 10 mm mesial and the other about 10 mm distal to 4P (test tooth). 3 months later, abutment connection was performed and healing allowed for one month. The dogs were randomly divided into 2 groups of 5 each, group A and group B. In group A, a fixed gold splint, rigidly connecting the tooth and the 2 implants, was installed on day 0 and 4P was hereby immobilized. The controlateral 4th premolar (P4) served as the non-splinted control tooth. Plaque control measures continued until the end of the experiment (day 180). In group B, plaque control measures were abandoned 1 month after abutment connection and a 4- month period of experimental periodontal tissue breakdown was initiated. This was accomplished by placing cotton floss ligatures submarginally around 4P and P4. At the end of this 4-month period, the ligatures were removed, and an apically positioned flap procedure was performed. Healing was allowed for another 2 months. Plaque control measures were re-established and continued throughout the experiment. A given day was termed day 0 and 4P was rigidly connected to the adjacent implants in the manner described for group A.(ABSTRACT TRUNCATED AT 250 WORDS)
Tooth eruption depends on bone resorption to form an eruption pathway. We have previously shown that a 2-wk local infusion of bafilomycin A1, an inhibitor of vacuolar H(+)-ATPases in osteoclasts, into the crypts of erupting mandibular premolars in dogs blocks bone resorption during this period and eruption of these teeth is delayed for 8 wk. Here we report the limits of inhibition of resorption that still permit eruption of these teeth. In 3 dogs 10(-6) M bafilomycin was delivered by osmotic minipumps early (18 wk) in eruption to the fourth premolar for 1, 3 or 4 wk. Radiographs taken at weekly intervals thereafter showed that bafilomycin delivery for 1 wk delayed eruption for 3 wk, delivery for 3 wk delayed eruption 9 wk and delivery for 4 wk prevented eruption. These data show that tooth eruption is delayed in direct proportion to the time resorption is blocked, and that this process for dog premolars cannot be blocked for more than 3 wk with 10(-6) M bafilomycin without blocking eruption itself.
A specific cementum attachment protein (CAP) was identified in human cementum and found to bind with high affinity to non-demineralized root surfaces, hydroxyapatite and fibronectin. Attempting to elucidate the biological function of this protein and its possible role in cementogenesis the capacity of CAP to promote selective cell migration towards and attachment of various periodontal derived cell populations to root surfaces in vitro was assessed. Human gingival fibroblasts (HGF), periodontal ligament cells (HPC), and alveolar bone cells (HABC) were labeled with [3H]Thymidine during their exponential growth phase. Root slices, 300 microns thick, were incubated with increasing concentrations of CAP. Untreated and fibronectin (FN) treated root slices served as negative and positive controls, respectively. Migration was assessed by placing root slices on confluent layers of labeled cells maintained in serum free medium and determining the number of cells migrated onto the root surface 3 days thereafter. Attachment was assessed by incubating root slices with labeled cell suspensions for 2 h and determining the number of attached cells. CAP promoted both cell migration and attachment dose dependently. HABC responded better than HPC and HGF to CAP treated root slices, and HPC response was higher than that of HGF. Cell attachment was dose dependently inhibited by synthetic RGD peptides. FN did not affect the migration of HGF, barely enhanced that of HABC, and was less potent than CAP at enhancing the migration of HPC. FN was more effective than CAP in promoting the attachment of HGF to root slices, but it was as potent as CAP in supporting the attachment of HPC and HABC.(ABSTRACT TRUNCATED AT 250 WORDS)