Efficacy of Various Subject Screening Measures: METHODS

In: Dental treatment

28 Feb 2010


Subjects consisted of 89 people who needed a minimum of two third molars extracted. Subjects were chosen based on a telephone interview and a questionnaire.

The telephone interview was carried out by an experienced psychologist. Recruitment was done by advertising on radio, in local and student newspapers, and on the University of Washington campus.

Screening Procedures

Subjects were recruited for a double-blind study testing different dosages of an experimental, fast-acting sedative agent designed to substitute for the use of nitrous oxide. A placebo was used as a control. Initial screening of subjects was done by telephone. The purpose of the telephone interview was to find out if a subject was fearful of third molar extractions and willing to participate in a study. Free third molar extractions were offered as compensation for participating in the study. To prevent candidates from lying about their fear of third molar extractions (ie, to prevent false positives), a scripted interview was carried out in the same way and order for all of the candidates who called. No information was given to the candidates about the requirement of being fearful. The candidates were asked if they had ever had any extractions and, if so, what kind of extraction. They were also asked if they had a clear idea about what was involved in the extraction of third molars. Candidates who were unclear about what was involved in extractions were informed of the procedures involved in third molar extractions (injection, opening the gum tissue, drilling, twisting, pulling, sutures). Candidates were then asked if they preferred no sedation, some sedation, or being asleep during this procedure. Candidates who claimed that they would not need a sedative during this extraction were excluded because of low fear levels. Once the interviewer knew they were fearful, the remaining candidates were informed that there was a 15% chance that they would get a placebo. Candidates who felt that being asleep was the only way of getting their third molars extracted and candidates who could not stand the chance that they might get a placebo generally self-selected themselves out of the study because of a fear level that was too high. All candidates had to be willing to take the risk of getting a placebo, even if they preferred a sedative. All subjects met other inclusion criteria as follows: (a) subjects were healthy, without any systemic diseases or psychiatric diagnoses, and were not taking medication for such conditions; (b) subjects’ height and weight were within normal ranges according to Metropolitan Insurance Company height and weight tables; and (c) subjects were not pregnant. Candidates deemed fearful in the telephone interview were mailed the recruitment questionnaires, which they filled out at home and mailed back. Candidates whose DAS score was greater than or equal to 10 were scheduled for an exam and X rays. The final selection criterion was that the candidates were required to have two third molars in need of extraction, with at least one of them impacted. canadian cialis online


Anxiety Before Oral Surgery. The Interval Scale of Anxiety Response (ISAR) was developed to measure anxiety regarding ongoing dental procedures. It consists of a 90-mm vertical line with descriptors aligned beside it at intervals determined by psychological scaling techniques. The descriptors are: “calm, relaxed” (4 mm), “a little nervous” (16 mm), “tense, upset” (26 mm), “afraid” (36 mm), “very afraid” (52 mm), “panicked” (66 mm) and “terrified” (84 mm). Subjects were instructed to mark the horizontal line with a pencil to indicate how they felt about their tooth extractions. This test was collected while subjects were waiting in the dental chair for their surgery to start, just before they received the sedative and 15 min before the actual surgery.

Recruitment Measures. The OSCQ was developed to assess pretreatment self-efficacy regarding coping with oral surgery. The questionnaire includes five questions regarding the subject’s confidence in his or her ability to exhibit behavioral coping (eg, keeping mouth open, staying relaxed) and six questions regarding the subject’s expectations about potential sensory (eg, pain) and affective (eg, nervous) experiences, including a question about the subject’s confidence in his or her ability to do well generally during the procedure. The subject rates himself or herself on each of the 11 items on the OSCQ, from 0 (not at all confident) to 9 (extremely confident). Subjects’ scores are totaled (0-99) for analysis. The OSCQ was developed to be a unidi-mensional measure (Litt, personal communication, 1998). The internal consistency of the OSCQ is reported to be good (Cronbach a = 0.90).

Self-reported dental anxiety was measured using the DAS. This instrument asks subjects to rate themselves on a scale of 1 to 5 on four items: anxiety about a hypothetical dental appointment that would occur the next day, anxiety in a dentist’s waiting room, anxiety while waiting for a tooth cleaning, and anxiety while waiting for drilling. Subjects’ scores are totaled (4-20) for analysis; a higher score indicates greater anxiety about dental procedures. A DAS score of 13 or higher indicates high dental fear.

The DFS was selected to assess specific aspects of dental fear in subjects. The DFS is a 20-item instrument with 5-point Likert-type scales that measure avoidance of dental treatment, fears of specific dental situations and procedures, and physiological upset during dental treatment. A score of 60 or greater is indicative of high dental fear.

The STAI consists of two separate self-reported psychometric scales. State anxiety refers to a transitory emotional condition with subjective feelings of apprehension, nervousness, worry, and increased activation of the autonomic nervous system. State anxiety may vary in intensity over time depending on the nature of situational stress. Trait anxiety describes relatively stable differences in individuals’ proneness to anxiety. The STAI state anxiety scale (STAI-S) consists of 20 items; subjects are asked to report how they feel at a particular moment in time by rating the intensity of their subjective feelings of anxiety (eg, “I feel frightened”) on a four-point scale from not at all (1) to very much so (4). The STAI trait anxiety scale (STAI-T) also consists of 20 items; subjects are required to indicate how they generally feel in response to each statement. In responding to each STAI-T item (eg, “I have disturbing thoughts”), subjects report how often they have experienced particular symptoms of anxiety by rating themselves on the following four-point frequency scale: (1) almost never, (2) sometimes, (3) often, and (4) almost always.

Previous Experience With Dental Extraction.

A panoramic radiograph was taken before oral surgery for each subject. Previous experience with dental extraction was determined from the radiographs. Subjects who did not have any missing permanent teeth were scored as having no previous experience with extraction during adulthood. In unclear cases (n = 13), subjects were contacted by telephone to determine previous experience with extraction as adults. Four of these subjects could not be reached.

Procedure the Day of Surgery

When subjects arrived, they filled out STAI-S and STAI-T tests. (As described above, other anxiety measures were filled out in advance for screening and returned by mail.) Subjects were then seated in a dental chair, where medical information was reviewed. Subjects filled out the ISAR and immediately afterward received the fast-acting sedative. Surgery was started 15 min after the subject received the sedative. Apcalis Oral Jelly


Simple descriptive statistics were obtained using the Statistical Package for the Social Sciences. Pearson correlations were used to test the associations between different measures. Linear regression analysis was used to determine which of the measures would best predict anxiety before surgery. In order to test the repeatability of the results, the data were randomly split into two parts, and the analysis was repeated in both subpopu-lations. Student’s t-test was used to test the differences in mean ISAR, STAI-S, STAI-T, OSCQ, DAS, and DFS scores between subjects with and without dental extraction experience.

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Blog invites submissions of review articles, reports on clinical techniques, case reports, conference summaries, and articles of opinion pertinent to the control of pain and anxiety in dentistry.