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Because of the wide variation found in Class II malocclusions, many different diagnostic decisions must be made. Treatment mechanics must, of necessity, differ. This case report describes the treatment of a Class II malocclusion which, for correction, required the extraction of maxillary first premolars and mandibular second premolars.
OBJECTIVE: A technique is presented for generating and recording lingual and palatine nerve somatosensory evoked potentials (SEPs). METHODS: Pairs of thin, stainless steel disk electrodes were mounted onto mandibular or maxillary acrylic splints, similar to orthodontic retainers. Mandibular splint electrodes were oriented to contact the under surface of the tongue along the course of the right and left lingual nerves and maxillary splint electrodes were oriented to contact the hard palate bilaterally along the course of the palatine nerves. SEP recording electrodes were placed on the scalp 1 cm posterior to C5 and C6 (C5' and C6', respectively) using the combinatorial nomenclature of the International 10-20 system. Two reference electrode locations, Fz and C5' or C6', over the cortical hemisphere opposite that of the recording electrode, were used. RESULTS: Right and left lingual and palatine nerve SEPs were recorded from five normal adults. SEP latencies were similar to the N13 and P18 cortical peak latencies recorded in previous studies of trigeminal nerve branches to the lips regardless of reference electrode position. CONCLUSIONS: A more precise method of stimulating the intraoral lingual and palatine nerves was accomplished using dental splints. SEPs were easier to obtain using a contralateral cortex reference electrode location.
OBJECTIVE: This study aimed to evaluate post-treatment changes at least five years out of retention in a cohort of 100 consecutively started patients treated by a postgraduate student in a UK orthodontic department. DESIGN: Analysis of study models using recognised occlusal indices. Setting Patients initially treated at Newcastle Dental Hospital were recalled for record collection. MATERIALS AND METHODS: Study models and clinical photographs were taken for each patient attending for post-retention records. Weighted Peer Assessment Rating (PAR) Index and Index of Orthodontic Treatment Need (IOTN) scores were recorded for cases at the beginning, end and at least 5 years post-retention. Main outcome measures Post-treatment changes were evaluated using PAR Index and IOTN to evaluate extent and likelihood of change and to compare treatment modalities. RESULTS: Seventy-eight patients attended for post-retention records. Overall PAR reduction immediately post-treatment was 68.6% and at a mean of 6.5 years post-retention was 55.5%. Dual arch fixed appliance treatments achieved the greatest reduction in PAR score, and maintained the reduction beyond the retention period better than other treatment modalities. Eighty-four per cent of the cohort still had some demonstrable improvement after a mean of 6.5 years post-retention. There was a residual need for treatment in 8% of cases on aesthetic grounds and in 24% of cases on dental health grounds. CONCLUSIONS: Occlusal deterioration after orthodontic treatment is almost universal. Dual arch fixed appliance treatment provides the best post-treatment and post-retention result.
Twenty-five patients who underwent early mixed dentition treatment were evaluated during the following stages: pretreatment (early mixed dentition), phase 2 (early permanent dentition), and postretention (average of 9.5 years). All patients were treated with a removable passive lingual arch. The mandibular incisors were judged to have satisfactory alignment at phase 2 evaluation and had no further orthodontic treatment. Nineteen of 25 cases (76%) demonstrated clinically satisfactory mandibular alignment postretention. Intercanine width decreased in 72% of the cases postretention and arch length decreased in 100% postretention. Intermolar width increased in 18 of 25 (72%) of the cases during treatment and remained stable in 17 of 25 (68%) of the cases. No predictors or associations could be found to help clinicians in determining the long-term prognosis of dental stability.
The purpose of this study was to evaluate the long-term stability of mandibular anterior alignment in a large group of Class II, Division 1, patients who demonstrated successful occlusal results at the end of active treatment. The specific aim was to search for predictors of relapse and associations between relapse and other post-retention changes. The sample of 78 adolescents was limited to successfully treated cases as judged by subjective evaluation of intercuspation and incisor occlusion of posttreatment study models. Neither cephalometric characteristics nor post-retention occlusion were considered in sample selection. Of these patients, study models and cephalograms were available pretreatment, at the end of active treatment, and a mean of 14 years post-retention. The results demonstrated an increase of incisor irregularity and a reduction of intercanine width and arch length post-retention. At post-retention, 9.0% had irregularity index values of 6.5 mm or more and 47.4% had values equal to 3.5 mm or less. Stepwise backward multiple regression analyses revealed that narrow pretreatment intercanine width and high pretreatment incisor irregularity were significant predictors of relapse. Treatment increase of intercanine width and post-retention decrease of intercanine width and arch length were associated with relapse.
The aim of this study was to analyze the efficiency of the mandibular banded and cast splint anchorage forms used in Herbst treatment. The records of 16 Class II:1 subjects treated with mandibular banded premolar anchorage (group A), 19 Class II:1 subjects treated with mandibular banded premolar-molar anchorage (group B), 34 Class II:1 subjects (group C), and 18 Class 11:2 subjects treated with mandibular cast splint anchorage (group D) were screened. The subjects in all four groups were treated for an average period of 0.6 years. Lateral head films were analyzed on four occasions ie, before treatment, after treatment, two years after, and four years after treatment. Mandibular anchorage loss during treatment was measured by the amount of anterior movement and proclination of the lower incisors as well as the anterior movement of the lower molars. During the treatment period a pronounced (P < .001) anchorage loss was found for all anchorage forms ie, incisor anterior movement/proclination as well as anterior movement of the lower molars. When comparing the cast splint anchorage in the Class II:1 and Class II: 2 cases, no difference was found with respect to the amount of mandibular anchorage loss of the incisors. After Herbst treatment, relapsing tooth movements were found in all three anchorage forms. It can be concluded that none of the three mandibular anchorage forms used in Herbst treatment could prevent an anchorage loss. Against all expectations, the cast splint anchorage was not better than the two banded anchorage forms.
This study aimed to assess mandibular mobility and the prevalence of functional occlusal contacts in subjects treated to a Class 1 incisor relationship by fixed orthodontic appliance therapy. Two hundred and thirty subjects participated (mean age=18 years) of whom 42 underwent orthognathic surgery. All subjects were in retention with a mean time of 7 months between debond and examination. Maximal mandibular opening, lateral and protrusive excursions were all significantly reduced in the surgical cases compared to the non-surgical group. Centric and eccentric non-ideal occlusal contacts were not different between surgical and non-surgical groups. Non-working side contacts occurred in 30% of subjects, posterior contacts on protrusion in 20% and RCP-ICP prematurities in 18% of subjects. Non-working side contacts were significantly more frequent in post-graduate cases compared to staff cases (P<0.05). An overbite less than the mean of 2.4 mm resulted in a reduced likelihood of canine guidance on the working side (P<0.001) and an increased frequency of non-working side contacts and posterior contacts on protrusion (P<0.001).
The skeletal stability of Le Fort I osteotomy was evaluated retrospectively in 14 patients with isolated cleft palate (CP, mean age 27.2 years) and 11 patients with bilateral cleft lip and palate (BCLP, mean age 23.7 years). The osteotomy was fixed with titanium plates and the osteotomy gap was grafted with autologous bone. Neither intermaxillary fixation nor occlusal splints were used postoperatively. Skeletal stability was analysed both horizontally and vertically by cephalograms taken shortly before operation, immediately afterwards, and at six months and at one year postoperatively. In the CP group the mean maxillary horizontal advancement (point A) was 4.7 mm (range 0.3-7.8) and the mean vertical lengthening 3.6 mm (range 0.7-6.1). One year postoperatively the mean relapse was 8.5% (0.4 mm) horizontally and 16.7% (0.6 mm) vertically. In the BCLP group the mean horizontal advancement was 5.3 mm (range 0.2-10.7) and the mean vertical lengthening 7.3 mm (range 0.6-11.8). The mean postoperative relapse was 9.4% (0.5 mm) horizontally and 17.8% (1.3 mm) vertically. The skeletal stability and relapse were similar in both cleft types although BCLP patients had more residual cleft problems and their mean surgical advancement was greater. There was great individual variation.
The purpose of this study was to use the Peer Assesment Rating (PAR) index score to evaluate the treatment and posttreatment changes of Class III patients treated by protraction facemask. The sample consisted of 20 Chinese children, 6 to 11 years old, with Class III skeletal malocclusion who had been treated with maxillary expansion and a protraction facemask. The average treatment time was 8.2 months, followed by 1 year of retention with a Class III functional appliance. Study casts were taken pretreatment (T1), posttreatment (T2), 1 year follow-up (T3), and 2 years follow-up (T4). After treatment, PAR scores were calculated for each time period. Differences among the 4 time periods were analyzed with the Wilcoxin matched-pairs test. Significant reductions in PAR scores were found at T2 (56%), T3 (70%), and T4 (63%) compared with T1. Immediately posttreatment (T2), 17 (85%) of 20 patients had improved PAR scores by a reduction of at least 30%. Reductions were caused primarily by correction of the anterior crossbite. One year after treatment (T3), further reductions in PAR score were noted (P <.01) as a result of better alignment of the anterior segment, improvement of the buccal occlusion, and overbite and midline corrections. Two years after treatment (T4), PAR scores were higher than at the previous time period. The increases were due to relapses in overjet (4 of 20 patients), overbite, and centerline corrections. These results indicate that significant reductions in the severity of Class III malocclusion can be achieved with early orthopedic facemask treatment. In most cases, further improvement in the PAR score can be expected 1 and 2 years after treatment. In a few patients, the benefits of early treatment are negated by relapses in overjet, overbite, and centerline corrections during the follow-up period.
A 26-year-old woman with dentofacial asymmetry shown by hemimandibular elongation and dental asymmetry was treated with a conservative orthodontic-prosthetic approach. The mechanics and sequence of treatment are described.
This case report describes the treatment of a patient with unerupted maxillary right central incisor, lateral incisor, and canine in a Class III malocclusion with asymmetry of the lower face. Sequential traction of the 3 unerupted teeth with a light force system was used in the treatment. The results remained stable during the 4-year retention period.
Long-term results from orthopedic management of skeletal Class III malocclusions are sparse. The purpose of this study was to evaluate the stability of results after facial growth and treatment with splints, Class III elastics, and chincup (SEC III) and to investigate the main determinants of relapse. Data from pretreatment, posttreatment, and long-term (at least 3 years after retention) serial cephalograms of 52 patients who received SEC III treatment were studied: only those with long-term data when growth had ceased (women over 18 and men over 21 years of age) were selected. At the end of the follow-up period (an average of 9 years), only 6 of the 52 patients had clinical relapse (overjet <or= 0). Low Wits appraisal, ANB angle, and overbite, and high SNB angle were the best predictors of relapse at the end of the treatment. Significantly greater decreases of the Wits appraisal and increases of ramus length during the follow-up were further associated with relapse. SEC III is a reliable treatment for skeletal Class III malocclusions. Long-term stability can be enhanced by a deeper overbite and the best possible skeletal correction. The results suggest that the correction occurs with no mandibular rotation but might be better with forward rotation.
The purpose of this study was to compare the dentoalveolar outcomes after 1-phase and 2-phase orthodontic treatment of Class II malocclusions. Class II subjects (n = 208) were randomized to 1-phase or 2-phase treatment with either bionator or headgear/biteplate. The peer assessment rating (PAR) was calculated from pretreatment, prephase 2, and final study models. Chi-square, Kruskal-Wallis, and Wilcoxon rank sum tests were used to evaluate the differences among treatment groups, sexes, races, pretreatment, mandibular plane angle, severity, and compliance. Spearman rank correlation coefficients were used to examine relationships between PAR at different times. The dropout rate of 24.6% did not adversely affect the ability to detect differences of clinical importance or impact treatment groups disproportionately. There were no significant differences with respect to initial PAR or final PAR among the 3 treatment protocols. The 2 early treatment groups had lower PAR scores than the 1-phase group before phase 2 (P =.0001). Lower PAR scores were achieved at both the beginning and end of phase 2 in girls (P =.03; P =.02, respectively). There were differences in the pre-phase-2 and post-phase-2 PAR scores based on initial severity (P =.0006; P =.02, respectively), with greater improvement in the patients whose malocclusions were less severe initially. Mandibular plane angle had no effect on pre-phase-2 or post-phase-2 PAR scores. These results do not support the hypothesis that different dentoalveolar outcomes are obtained between 2-phase and 1-phase treatment of Class II malocclusions.
To assess the outcome of orthodontic treatment, 224 cases treated in a postgraduate clinic were evaluated. Pre-treatment (T1), post-treatment (T2) and 5-year follow-up (T3) study casts were assessed by the Peer Assessment Rating (PAR) Index. The influence of various factors upon treatment and long-term outcome was analysed. According to the PAR Index, orthodontic treatment reduced the malocclusions on average by 76.7 per cent, and at follow-up the reduction was 63.8 per cent. Follow-up stability was good for 76.3 per cent of the cases. Some cases (4.0 per cent) even improved, while moderate to severe post-treatment relapse occurred in 19.7 per cent of the cases. Orthodontic treatment changed Angle Class I, II and III malocclusions to near ideal occlusion (PAR scores 4.4-6.8). No long-term interaction between the groups was discovered. Sex and extraction/non-extraction treatments did not significantly affect the results. The initial PAR score accounted for 77.8 per cent of the variation in treatment PAR score change (T1-T2), and for 61.8 per cent of the variation of long-term PAR score change (T1-T3). Age at treatment start accounted significantly for the variability of treatment changes (P < 0.001). The PAR score at the end of treatment had some explanatory importance (R2 = 0.099) for the long-term (T1-T3) result. However, PAR score changes in the follow-up period were difficult to predict.
Bone scintigraphy results were compared with changes shown on orthopantomographic radiographs in a patient with facial asymmetry, before, during, and after Herbst treatment, and followed up with control of growth activity in the temporomandibular joints (TMJs) after long-term retention. The present study showed that new bone formation (modelling) was initiated asymmetrically in TMJs during treatment. The results indicate that late development of right/left asymmetry in the occlusion can be corrected and normalized using the Herbst appliance therapy, stimulating a differentiated 'catch up' growth (modelling) in the TMJ with condyles. After treatment, original growth with asymmetric activity in the TMJ was re-established. This growth activity may re-establish the asymmetry in the sagittal occlusion and the face of the patient. It is therefore recommended that the occlusion should be maintained with an appliance which stabilizes the occlusion until cessation of the primary, endochondral growth.
Fifteen patients, eight males and seven females with a mean age of 13.32 years, were selected for unilateral molar distalization. Dentally, all presented with a unilateral Class II molar relationship. The subjects were all in the permanent dentition with second molars erupted and with a well aligned lower dental arch. For maxillary molar distalization a new intra-oral appliance was developed, the Keles Slider, which comprised two premolar and two molar bands. The anchorage unit was a Nance button with an anterior bite plane. From the palatal side, the point of distal force application was carried towards the level of centre of resistance of the maxillary first molar. A Ni-Ti coil spring was used and 200 g distal force was applied to the Class II first molar. Lateral cephalograms were taken and analysed before and 2 months after molar distalization. The Class II molars were distalized bodily, on average, 4.9 mm (P < 0.001). Mesial migration of the Class II first premolars was 1.3 mm (P < 0.05), incisor protrusion was 1.8 mm (P < 0.05) and incisor proclination 3.2 degrees (P < 0.05). The overbite was reduced by 3.1 mm (P < 0.001) and the overjet increased 2.1 mm (P < 0.01). For stabilization, the corrected Class II unilateral molar relationship was maintained with a Nance button for 2 months. The results show that this newly developed device achieved bodily distal molar movement with minimum anchorage loss.
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