Efficacy of Chewing Gum to Reduce Orthodontic Pain Compared to Placebo: A Blinded, Parallel-Group, Preliminary Clinical Trial.

AIMS: To quantify the pain experienced by orthodontic patients during the first 10 days of appliance placement, to determine whether chewing gum reduces orthodontic pain compared to placebo, and to examine patients' overall perceptions of the impact of orthodontic pain. METHODS: Patients bonded with fixed appliances were randomly assigned to one of two groups (gum group [GG] or placebo group [PG]) and then followed for 10 days. The main outcome was a visual analog scale (VAS) pain score, and the secondary outcomes included patients' subjective assessments of overall pain level, the impact of pain on hygiene habits and treatment decision, and the frequency of analgesics consumption. Eighty kits (40 for GG and 40 for PG) were pre-randomized and concealed before patient enrollment using a computer-generated random sequence. Operators and patients were blinded. Data were analyzed using generalized linear models and Mann-Whitney U, chi-square, and Fisher exact tests. RESULTS: A total of 75 patients were allocated to intervention groups; 37 participated and completed diaries (20 in GG and 17 in PG). No statistically significant differences were detected between the GG and PG groups in any tested variable. Pain negatively affected some patients' oral hygiene practices. A mismatch existed between patient expectations and actual pain experiences. Female patients used analgesics more frequently than male patients (P = .046). CONCLUSION: Chewing gum three times per day does not seem to significantly reduce orthodontic pain compared to placebo. Orthodontists should manage their patients' pain expectations.

Cone-beam computed tomography transverse analyses. Part 2: Measures of performance.

INTRODUCTION: The aim of this study was to compare the predictability of the cone-beam transverse (CBT), jugale (J-point), and transpalatal width measurement (TWM) analyses in identifying clinical crossbite. METHODS: From a pool of patients with cone-beam computed tomography scans who came for orthodontic treatment, a sample of 133 patients was identified, with 54 in posterior crossbite (28 boys, 26 girls) and 79 not in crossbite (77 boys, 110 girls). No patient had dental compensation in this sample. After correcting for lateral mandibular shift, 33 of the 54 posterior crossbite patients had a bilateral crossbite, and 21 had a unilateral crossbite with no shift. The CBT, J-point, and TWM analyses were done for each patient from a coronal cross-section through the middle of both the maxillary and mandibular first molar crowns. The landmarks and measurements used were described in detail in a previous study. Posteroanterior cephalograms were constructed to simulate the geometry of the conventional cephalometric radiographs. All 3 analyses were performed on the same data set to predict whether crossbite was present. We used 2 assessments of diagnostic predictability: sensitivity and specificity, and positive and negative predictive values. While the 2 methods answer different questions, the prevalence of crossbite in a population will affect the positive and negative predictive values, but the sensitivity and specificity will not change. RESULTS: Of the 133 patients studied, 54 had a clinical crossbite, and 79 had no crossbite. The J-point analysis accurately predicted that 38 patients would have a crossbite, and 45 would not. This resulted in a positive predictive value of 52.78%, a negative predictive value of 73.77%, sensitivity of 70.4%, and specificity of 57%. The TWM analysis accurately predicted that 53 patients would have a crossbite, but it falsely predicted that an additional 68 patients would have crossbite. This resulted in a positive predictive value of 43.8%, a negative predictive value of 91.67%, sensitivity of 98.1%, and specificity of 13.9%. The CBT analysis correctly predicted a crossbite in 47 patients and accurately predicted no crossbite in 73 patients. This resulted in a positive predictive value of 88.68%, a negative predictive value of 91.25%, sensitivity of 87.0%, and specificity of 92.4%. CONCLUSIONS: This study showed that although the TWM analysis had slightly better negative predictive and sensitivity values, the CBT analysis was overall better at both predictive value and sensitivity/specificity because of the limitations in J-point landmarks and the extent of the TWM analysis. Furthermore, the CBT analysis can distinguish between skeletal and dental discrepancies. Further work will test the analysis on additional samples with differing prevalences of crossbite.

Cone-beam computed tomography transverse analysis. Part I: Normative data.

INTRODUCTION: The application of cone-beam computed tomography (CBCT) in orthodontics ushered in a new era in 3-dimensional analysis that promises to provide more comprehensive understanding of craniofacial skeletal anatomy. That promise is now being realized in multiple studies. The purposes of this study were to investigate a portion of transverse dimension relationships by using CBCT and to propose a transverse analysis to assist practitioners with treatment decisions. METHODS: The CBCT scans of 241 patients with and without crossbite were analyzed to assess the width of the jaws and the inclination of the first molars. The dental and skeletal measurements were compared between the noncrossbite and the crossbite groups. RESULTS: The noncrossbite group included patients who had apparently normal transverse relationships, but also a surprising number of patients with an obvious skeletal transverse discrepancy masked by dental compensation. The noncrossbite patients with molar inclinations within 1 SD of the mean were defined as the control group, and those with dental compensations were identified as either superior convergent or inferior convergent. The obvious unilateral crossbite patients demonstrated dental compensation in the maxillary first molar on the noncrossbite side, whereas the obvious bilateral crossbite patients had normal dental inclinations. CONCLUSIONS: Skeletally, both the bilateral and unilateral crossbite groups had narrower maxillary widths than did the controls, but also wider mandibles, with more severe bilateral crossbites. Dentally, the unilateral crossbite group had more upright teeth on the noncrossbite side. In the noncrossbite groups with dental compensations, the superior convergent and inferior convergent differences in both dental and skeletal characteristics were marked. Patients without crossbites can have significant discrepancies that might warrant treatment.