Your goal is to extract structured information from the user's input that matches the form described below. When extracting information please make sure it matches the type information exactly. Do not add any attributes that do not appear in the schema shown below.

```TypeScript

 { // Information on the clinical trial characteristics from the abstract
 conditions: string // The condition or disease being treated in the clinical trial
 drug_or_intervention: string // The drug or intervention used in the clinical trial
}
```


Please output the extracted information in JSON format. Do not output anything except for the extracted information. Do not add any clarifying information. Do not add any fields that are not in the schema. If the text contains attributes that do not appear in the schema, please ignore them. All output must be in JSON format and follow the schema specified above. Wrap the JSON in <json> tags.



Input:Staining and calculus formation after 0.12% chlorhexidine rinses in plaque-free and plaque covered surfaces: a randomized trial.  Studies concerning side effects of chlorhexidine as related to the presence of plaque are scarce. The purpose of this study was to compare the side effects of 0.12% chlorhexidine gluconate (CHX) on previously plaque-free (control group) and plaque-covered surfaces (test group). This study had a single-blind, randomized, split-mouth, 21 days-experimental gingivitis design, including 20 individuals who abandoned all mechanical plaque control methods during 25 days. After 4 days of plaque accumulation, the individuals had 2 randomized quadrants cleaned, remaining 2 quadrants with plaque-covered dental surfaces. On the fourth day, the individuals started with 0.12% CHX rinsing lasting for 21 days. Stain index intensity and extent as well as calculus formation were evaluated during the experimental period. Intergroup comparisons showed statistically higher (p<0.05) stain intensity and extent index as well as calculus formation over the study in test surfaces as compared to control surfaces. Thus, 26.19% of test surfaces presented calculus, whereas calculus was observed in 4.52% in control surfaces. The presence of plaque increased 0.12% CHX side effects. These results strengthen the necessity of biofilm disruption prior to the start of CHX mouthrinses in order to reduce side effects. Output:
{'conditions': 'Dental Calculus|Tooth Discoloration', 'interventions': 'Other: Dental prophylaxis'}