John W. Harrison

Analysis of the effect of dilution on the necrotic tissue dissolution property of sodium hypochlorite

Dilution of 5.25% sodium hypochlorite before its use as an endodontic irrigant has been recommended. The effect of dilution on the solvent action of sodium hypochlorite was investigated in vitro. Under controlled conditions, necrotic tissue specimens were exposed to various concentrations of sodium hypochlorite and the percent of tissue weight change was determined. Statistical analysis indicated that dilution of 5.25% sodium hypochlorite resulted in a significant decrease in the ability to dissolve necrotic tissue.

Incidence of pain associated with clinical factors during and after root canal therapy. Part 2. Postobturation pain

Patients who begin endodontic therapy with nosymptoms may experience pain during therapy or after obturation of the canal system. Part 2 of this study analyzed the relationship between postobturation pain and clinical factors or conditions existing before, during, and after root canal therapy. Significant relationships were found between postobturation pain and interappointment pain and between postobturation pain and the type of chemical agents used for irrigation and intracanal medication. Of the 229 patients included in this study, 109 (47.6%) reported postobturation pain at some time during the 60-day postobturation observation period. The highest incidence and degree of postobturation pain occurred during the first 24 h. Sixty days after obturation, 227 (99.1%) patients were free of symptoms.

The effect of dilution and organic matter on the antibacterial property of 5.25% sodium hypochlorite

Absorbent points were contaminated with Streptococcus faecalis and exposed for varying time intervals to concentrations of sodium hypochlorite and to 5.25% sodium hypochlorite mixed with organic matter. After exposure to one of the test solutions, the absorbent points were placed in a culture medium and incubated; the presence of growth was recorded. Results showed that dilution of 5.25% sodium hypochlorite inhibits its antibacterial property significantly. The presence of organic matter reduced the antibacterial property of 5.25% sodium hypochlorite from no inhibition to significant inhibition.

Chemomechanical removal of pulpal and dentinal debris with sodium hypochlorite and hydrogen peroxide vs normal saline solution

The effectiveness of chemomechanical preparation with normal saline solution and with a combination of sodium hypochlorite and hydrogen peroxide was evaluated microscopically. The results indicated that a combination of NaOCl and H 2 O 2 was significantly more effective in cleansing the canal system at 1 and 3 mm from the apex. At the 5-mm level, normal saline solution was equally effective as an irrigant.

Incidence of pain associated with clinical factors during and after root canal therapy. Part 1. Interappointment pain

Patients who begin endodontic therapy with no symptoms may experience pain during therapy or after obturation of the canal system. A clinical study was conducted to determine whether any clinical factors or conditions are associated with an increased incidence or degree of interappointment or postobturation pain. Of 229 patients evaluated in part 1 of this study, 28.8% had slight interappointment pain and 15.7% had moderate to severe pain. Statistical analysis showed no significant relationship between interappointment pain and any of the analyzed clinical factors or conditions.

The incidence of bacteremias related to endodontic procedures I. Nonsurgical endodontics

Blood samples were taken from 30 patients immediately after various nonsurgical endodontic procedures. The incidence of bacteremias produced by these procedures was determined and quantitated. The source of the blood-borne microorganisms was confirmed as the pulp cavity. The results indicate that bacteremias are not produced when endodontic manipulations are confined to the root canal system.

Analysis of clinical toxicity of endodontic irrigants.

A clinical investigation was conducted to determine the effect of the use of various endodontic irrigants on interappointment pain. Of 253 patients who were treated, 65.6% were free of interappointment symptoms, 27.7% had slight pain, and 6.7% had pain that required palliative treatment. Statistical analysis showed no relationship between interappointment pain and the type of irrigant used.

Incidence of bacteremias related to endodontic procedures.

Abstract Blood samples were taken from patients immediately after specific surgical endodontic procedures and immediately after single-tooth extractions. The incidence of bacteremias produced by these procedures was determined. The source of the blood-borne micro organisms was confirmed as the operative site.

Analysis of interappointment pain associated with the combined use of endodontic irrigants and medicaments

Laboratory studies have shown that certain irrigants and intracanal medicaments used in endodontic treatment have a high potential for toxicity. A clinical study was conducted to determine the effect on interappointment pain of the combined use of irrigants and medicaments with a potential for toxicity. Statistical analysis showed no significant relationship between the incidence or degree of interappointment pain and the combinations of chemical agents used during endodontic therapy. Of 245 cases treated, 76.7% were free of interappointment symptoms, 17.6% had slight pain, and 5.7% had pain that required palliative treatment.

Wound healing following demineralization of resected root ends in periradicular surgery.

The objective of this study was to determine the effect of demineralization of resected root ends on the temporal and qualitative healing of the dentoalveolar (apical attachment apparatus) and alveolar (osseous) tissues in the excisional wound site created during periradicular surgery. Root end resections to orthograde gutta-percha obturations were performed on the mandibular premolars of six mongrel dogs. Twenty-four experimental root ends were demineralized by citric acid burnishing of the resected surfaces. The remaining 24 standard treatment root ends were not demineralized. Microscopic evaluations at postsurgical intervals from 4 to 45 days revealed that the demineralized root ends were associated with more rapid and complete healing than the nondemineralized root ends. It is proposed that demineralization enhances cementogenesis, the key to dentoalveolar healing, by removing the smear layer barrier and exposing the organic component (collagen fibrils) of resected cementum and dentin.