VALIDATION OF A 21-DAY, PARTIAL-MOUTH GINGIVITIS MODEL FOR EVALUATINGCHEMOTHERAPEUTIC DENTIFRICES

The experimental gingivitis model has long been used to evaluate chemo therapeutic agents in mouthrinses. Only recently however has the model been modified to test undiluted dentifrices by using a toothshield bo th to apply dentifrice and to protect selected teeth from toothbrushin g. This also enables participants to brush the rest of the mouth and a void the unpleasantness of 3 weeks without oral hygiene. Because of it s well-documented efficacy, chlorhexidine was used in a toothpaste for mulation to investigate the validity of the partial-mouth, experimenta l gingivitis model for evaluating therapeutic dentifrices. Optimal gin gival health was established in 88 adults, who then were randomly assi gned to two equal groups. A toothshield was constructed for each subje ct to fit the teeth of one mandibular quadrant. During the trial chlor hexidine or placebo dentifrice was applied undiluted to the test teeth via the toothshield, which also prevented plaque removal during brush ing of the remaining dentition. After 21 days, plaque and gingivitis h ad developed in both groups. However, the chlorhexidine group had sign ificantly less plaque and gingivitis than the placebo group. No advers e soft tissue effects were observed. This study demonstrated that the partial-mouth, experimental gingivitis model allowed unhindered develo pment of plaque and gingivitis that was comparable to whole-mouth stud ies in which oral hygiene was suspended for 3 weeks. By corroborating with chlorhexidine, it is concluded that this short-term clinical mode l is valid for evaluating the chemotherapeutic effects of dentifrices.