Evaluation of a sterile pulpotomy procedure

Abstract

Pulpotomy procedures for the treatment of pulp exposure or disease have traditionally used an approach from the occlusal surface in primary molars, with a rotating bur or a spoon excavator being used to excise the pulp under clean conditions and with a medicament being applied to the amputation site. The purpose of this study was: (1) to determine the feasibility of performing a sterile scalpel excision of coronal pulpal tissue and (2) to evaluate wound healing after a shield has been placed to prevent all substances from touching the blood clot at the amputation site. Using sterile operating room procedures, four of five teeth in five dogs were rendered free of cultivable bacteria after antimicrobial treatments were applied. These findings replicated a preliminary in vivo experiment of 45 teeth which demonstrated that antimicrobial agents applied to tooth enamel in dogs were effective beyond the 0.001 level of significance, as compared to a control group. Furthermore, in the main study, negative cultures were obtained during 72 percent of the trials following each of the five major steps in the pulpotomy procedure. This included 80 percent negative cultures for bacteria after pulpal excision and blood clot formation, and 100 percent freedom from cultivable bacteria after a resin diaphragm was cemented to place. In eight experimental teeth (three from the preliminary study and all five from the main study) the buccal dentin over the coronal portion of the pulp was removed by use of a tissue-protecting device without grossly macerating the pulpal tissue. In seven of these eight teeth, the coronal portion of the pulp tissue was amputated with a scalpel severance and pulpal biopsies were removed through the buccal preparation. In all eight teeth, the cavity preparation was accomplished without applying medicaments to the blood clot at the amputation site. A resin-stainless steel diaphragm was constructed under sterile conditions and secured in a buccal preparation without touching the pulpal amputation for a convalescence of 14-21 days, and this shield provided a buccal wall for closure with an amalgam restoration. In one animal which had not received a previous autotransfusion for medical research, histologic sections of the pulp tissue in two root canals demonstrated satisfactory wound healing (a moderate and a mild inflammatory infiltrate was considered reversible). Three of the five dogs in the main study exhibited pulpal necrosis which was attributed to an interference in the immune system by previous autotransfusion research, and histologic evaluation of pulpal wound healing was therefore inconclusive. This study demonstrates that the enamel surface can be rendered free of cultivable bacteria in the dog and the operative site can be maintained in this condition throughout pulpotomy, with the coronal portion of the pulp being removed without grossly macerating the pulp. Under these conditions there appears to be a potential for satisfactory wound healing, with possible implications for the clinical situation.