The aims of this study were to assess the peer assessment rating (PAR) index in relation to perceived treatment needs for maxillary protrusion in Japanese subjects and to investigate how perceived orthodontic treatment needs change with increased experience in dentistry and orthodontics.
The subjects were 155 persons (73 men, 82 women; mean age, 24.2 years; SD, 4.7 years) including dental students, residents, and orthodontists. We showed them casts from 10 patients with untreated maxillary protrusion and gave them a questionnaire with a 100-point visual analog scale (VAS), concerning their perceptions of orthodontic treatment needs. The PAR index was used for cast evaluation.
The PAR index showed significant correlations with the VAS scores. On the casts evaluated with a PAR index below 17, there was no difference in VAS scores between the 3 groups; however, orthodontists perceived significantly greater treatment needs than did students and residents on casts with a PAR index of 18 or 19. The VAS scores were significantly increased when casts with a PAR index of more than 20 and overjet above 5.0 mm were evaluated. Orthodontists and residents perceived greater treatment needs than students on assessing occlusions with severe maxillary protrusion.
The PAR index is clinically useful to evaluate malocclusion, and the perception of treatment needs was significantly greater when the maxillary protrusion cast had a PAR index of more than 20 and overjet above 5.0 mm. Perceived needs for orthodontic treatment for maxillary protrusion changed with increasing experience and skills in dentistry and orthodontics.
Most patients who visit orthodontic clinics complain of esthetic problems regarding their teeth or facial appearance; however, their decisions to seek orthodontic treatment are often based on several factors. Some visit orthodontic clinics independently or are persuaded by their family, whereas others might be recommended by their family dentist. The perception of orthodontic treatment needs might be related to several factors: ethnic group, age, sex, and regional or professional background. Some studies indicated that the recognition of orthodontic treatment needs differed between patients and dentists. In addition, because of possible differences in dental education, the perception of orthodontic treatment needs can differ even among dentists, including orthodontists, pediatric dentists, general dentists, and oral surgeons. The subdivision of this specialized field is advancing in modern dentistry, and cooperation between dentists is necessary to provide comprehensive dental treatment. Therefore, it is important for orthodontists to understand the differences in perceived orthodontic treatment needs between dentists. However, few studies have investigated in detail how differences in perceived needs for orthodontic treatment change with increased experience and skills.
The peer assessment rating (PAR) indexwas developed to provide a single summary score for all occlusal anomalies in a malocclusion and is often used by orthodontists to evaluate malocclusions objectively. Recently, the PAR index has also been used as an assessment tool to evaluate orthodontic treatment outcomes. In addition, the PAR index is considered an excellent predictor of orthodontic treatment needs by orthodontic experts. Nevertheless, it is still unknown whether the PAR index reflects the perception of treatment needs of laypersons and dentists except for orthodontists.
The aims of this study were to assess the PAR index in relation to the perceived treatment needs for maxillary protrusion in Japanese subjects and to investigate how this perception changes with increasing experience and skills in dentistry and orthodontics.
Material and methods
The subjects in this study were 155 persons (73 men, 82 women; mean age, 24.2 years; SD, 4.7 years), including 99 undergraduate students (47 men, 52 women; mean age, 21.8 years; SD, 1.6 years) from Okayama University Dental School and 29 residents (9 men, 20 women; mean age, 25.4 years; SD, 1.8 years) and 27 orthodontists (17 men, 10 women; mean age, 31.8 years; SD, 5.8 years) form Okayama University Hospital. No undergraduate student had received clinical training.
Dental casts of 10 patients with untreated maxillary protrusion were selected to show an increase in overjet sequentially (1.8-11.6 mm); those with moderate or severe crowding were excluded ( Fig 1 ). The PAR index was calculated 3 times for each dental cast by 3 investigators (S.U., M.S., R.K.) who had been calibrated. We randomly displayed the casts and gave a questionnaire to the subjects with a 100-point visual analog scale (VAS) concerning perception of orthodontic treatment needs. The VAS was a 100-mm line with anchors at each end of “no need to treat” (0 mm) and “strongly perceived treatment needs” (100 mm).