PubMed · 503052
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C B Quick, V T Rendano. 1979. The equine teeth.. https://pubmed.ncbi.nlm.nih.gov/503052/
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Little is known about local bone regulation that enables spontaneous molar tooth drift. In this study the role of prostaglandins (PGs) were investigated in the rat by inhibiting PG-synthesis with indomethacin (7 mg/kg/d). Untreated animals were killed at the start of the experiment, while treated ones were killed after 3, 7, or 14 days of treatment. Mandibles were processed for histomorphometry without demineralization. Changes in osteoclasts and extent of the different steps of the bone remodeling sequence (resorption, reversal, and formation) were assessed along the remodeling side of the socket of the buccal root of the first molar. The total number of osteoclasts decreased after 7 days of PG inhibition (P < 0.01 vs controls) and then partially recovered. This change was due to a sharp decrease in active cells on day 7 (P < 0.01), while inactive cells remained unchanged throughout the experimental period. The extent of resorption fell on day 7 (P < 0.01) and then recovered almost to the control level on day 14. Reversal at first increased insignificantly and thereafter decreased (P < 0.02) for the remaining 7 days. Formation was modified only on day 14; at that time it had doubled compared with controls. These results show that PGs are involved in the local regulation of bone remodeling accompanying tooth drift. Resorption inhibition was partial, indicating that other factors participate with PGs in this regulation; in addition, the trend to recovery observed at the end of the experimental period suggests that these factors can take over from PGs to achieve the necessary remodeling of the socket.
A three-dimensional mathematical model was generated, representing a three-unit cantilever fixed partial denture and its supporting mandibular structures. First and second premolars were used as abutments with one posterior cantilever pontic. A 5 lb vertical load was applied to the pontic. Vertical and horizontal stresses were analyzed by means of a three-dimensional finite element stress analysis technique. The results showed that a cantilever pontic creates considerable compressive stress on the abutment nearest to the pontic and produces tensile stress on the abutment farthest from the pontic.
The techniques currently used for standardized longitudinal radiographic evaluation of the supporting bone around dental implants are not suitable for general application. An aiming device is described for intraoral radiography used to evaluate the crestal bone height around dental implants used as retention for overdentures. This aiming device has been tested on four different implant systems by four dentists. Error analysis of serial radiographs indicates small deviations in reproducibility. It is concluded that this method is suitable for routine evaluation of dental implants.