A comparison of orthodontic treatment outcomes using the Objective Grading System (OGS) and the Peer Assessment Rating (PAR) index.

INTRODUCTION: The use of objective criteria is essential to uniformly quantify and measure the severity of malocclusions and the efficacy of different treatment modalities. The Peer Assessment Rating (PAR) index and, more recently, the American Board of Orthodontics Objective Grading System (OGS) were developed to fulfill this need. AIM: The aim of this retrospective study was to assess and compare treatment outcomes using the UK and US weighted PAR and the OGS. MATERIALS AND METHODS: The sample consisted of randomly selected records of 50 patients treated by residents in one postgraduate orthodontic clinic. UK and US weightings for the PAR index were applied and compared with OGS. RESULTS: There was no statistically significant association between the OGS and the PAR index grading systems. Neither the UK nor the US PAR weightings showed statistically significant correlation with the OGS. All cases were 'greatly improved' or 'improved' according to the PAR index, while most cases (62%) failed according to OGS. There was a statistically significant correlation between the unweighted PAR index and the OGS (r = -0.32, p = 0.024). The US and the UK weightings for the PAR were highly correlated (r = 0.90, p < 0.001). Both weighting systems were also highly correlated with the unweighted PAR (p < 0.001). There were no gender differences found in any of the scoring systems. CONCLUSIONS: The current PAR index cannot replace the OGS for evaluating treatment outcomes. The current OGS cannot detect the improvement achieved in a treated case.

Long-term effectiveness of the continuous and the sectional archwire techniques in leveling the curve of Spee.

INTRODUCTION: The correction of a deep overbite with the subsequent achievement of long-term stability is a difficult problem for orthodontists. The role of leveling the curve of Spee (COS) in bite opening and the success of orthodontic treatment has been well documented in the literature. The aim of this study was to investigate whether leveling the COS, by using 2 orthodontic treatment techniques, produces stable results on a long-term basis. METHODS: We compared the long-term stability of leveling the COS with the straight-wire Alexander technique and the bioprogressive sectional-arch technique. The randomly selected subjects for this retrospective study were obtained from the private practices of Drs R. G. Alexander and Ruel Bench. Study models taken 2 months before treatment (T1), 2 months after treatment (T2), and after retention (T3) were evaluated. Measurements of the COS were made on the mandibular casts with a commercially available palatometer. Mandibular intercanine width, overbite, overjet, mandibular incisor irregularity, and mandibular arch length were also recorded. RESULTS AND CONCLUSIONS: Both techniques produced highly significant reductions in the COS (T1 to T2). Statistically significant, but clinically insignificant, postretention relapse of the COS occurred (T2 to T3). For both techniques, a statistically significant difference was seen in the incidence of the relapse of the COS between patients who were completely leveled posttreatment and those who were not. We did not find a correlation between pretreatment COS and relapse in any of the other occlusal traits studied.