Overbite Reduction Research Articles

Absolute anchorage with universal t-loop mechanics for severe deepbite and maxillary anterior protrusion and its 10-year stability

An adult patient with severe maxillary protrusion and deepbite who was congenitally missing two mandibular incisors was treated successfully by maximum retraction of the maxillary anterior teeth after extraction of the maxillary first premolars using a moment differential between the anterior and posterior segments created by a universal T-loop. Anterior teeth were moved with controlled tipping, and little anchorage loss of the posterior segments was experienced using the universal T-loop spring. Reduction of overbite was performed by absolute intrusion of both maxillary and mandibular anterior teeth. With retraction of the maxillary anterior teeth and recontouring of the mandibular canines, proper overjet and overbite were achieved. This report shows the 10-year stability of the case treated with the universal T-loop for the first time.

Efeitos do aparelho Jasper Jumper no tratamento da má oclusão de Classe II

OBJETIVO: o objetivo deste estudo foi avaliar os efeitos esqueléticos e dentoalveolares do tratamento de pacientes com má oclusão de Classe II com o aparelho Jasper Jumper associado ao aparelho ortodôntico fixo, comparados a um grupo controle não-tratado. MÉTODOS: a amostra foi constituída por 47 indivíduos, divididos em dois grupos: Grupo 1, contendo 25 pacientes com idade média de 12,72 anos, tratados com o aparelho Jasper Jumper por um tempo médio de 2,15 anos; Grupo 2 (controle), composto por 22 indivíduos com idade média de 12,67 anos, não-submetidos a tratamento ortodôntico e com má oclusão de Classe II, observados por um período médio de 2,12 anos. Foram avaliadas as telerradiografias ao início e ao final do tratamento ortodôntico para o Grupo 1 e do período de observação para o Grupo 2. As variáveis cefalométricas iniciais, finais e as alterações com o tratamento foram comparadas entre os grupos por meio do teste t independente. RESULTADOS: em comparação ao grupo controle, o grupo Jasper Jumper apresentou maior restrição do deslocamento anterior da maxila e maior retrusão maxilar, melhora da relação maxilomandibular, diminuição da convexidade facial, maior protrusão e intrusão dos incisivos inferiores e maior extrusão dos molares inferiores, além de maior diminuição dos trespasses horizontal e vertical e maior melhora da relação molar. CONCLUSÃO: a correção da Classe II no grupo tratado com o Jasper Jumper e aparelhagem fixa se deu principalmente devido à restrição do crescimento maxilar, protrusão e intrusão dos incisivos inferiores e extrusão dos molares inferiores.

Combined Treatment of Open Bite – Long-term Evaluation and Relapse Factors

Some patients with open bite who have been treated with combined fixed orthodontic appliances and bimaxillary osteotomy relapse in the vertical dimension after the end of treatment following initially successful correction of the vertical dimension. The aim of this study was to identify those parameters that raise the tendency to relapse. Nineteen patients who underwent combined treatment using fixed orthodontic appliances and bimaxillary osteotomy due to open bite (overbite < 0 mm), were examined and documented at least 2 years after surgery. Pre- and post-orthodontic and pre- and post-operative study models and lateral head films were analyzed. Overbite reduction after the end of treatment was considered as relapse. In our study cohort, the appearance of relapse in the vertical correlated with the enlargement of Björk's sum angle (odds ratio 10.7) and Jarabak's ratio (odds ratio 7) by means of surgery, as well as with dysfunctional habits persisting after treatment such as mouth breathing (odds ratio 12.5) and a visceral swallowing pattern (odds ratio 8.3). The existence at baseline of isolated anteinclination of the anterior maxilla or isolated steep inclination of the mandible also made vertical relapse more probable (odds ratio 7.5). Particularly deserving of attention during the combined interdisciplinary treatment of patients with open bite are the achieved reduction in posterior facial height by surgical posterior impaction of the maxilla, as well as correction of dysfunctional parameters during swallowing and breathing.

Long-term stability of dentoalveolar and skeletal changes after activator-headgear treatment

The aim of this study was to analyze the long-term stability of combined activator-headgear treatment on skeletal and dental structures in Class II patients. The material comprised 26 subjects, 10 girls and 16 boys. All had a molar Class II relationship, overjet > or =6 mm, and overbite > or =5 mm. They were treated in one practice with combined activator and headgear appliances. Lateral cephalometric radiographs and dental study casts were taken before treatment (T0, mean age 11.9 years), at the end of activator-headgear treatment (T1, mean age 15.9 years), and 12-15 years out of retention (T2, mean age 28.6 years). Nineteen cephalometric and nine dental cast variables were evaluated using a paired sample t-test between T0-T1, T1-T2, and T0-T2. At T1, the majority of the cephalometric measurements showed statistically significant changes. ANB was significantly reduced by 2.3 degrees due to a significant increase in SNB, but only small changes were observed in SNA. The interincisal angle increased as a result of significant retroclination of both maxillary and mandibular incisors. All patients achieved a Class I molar relationship and a significant reduction in overjet and overbite. At T2, the results showed only slight relapse from T1. However, the relapse did not compromise the significant improvement in almost all the cephalometric and dental variables. Combined activator-headgear treatment improved the skeletal and dental conditions and the results remained stable in the long term.

Comparison of the effects produced by headgear and pendulum appliances followed by fixed orthodontic treatment

This study compared the effects produced by two different molar distalizers, namely cervical headgear (CHG) and the intraoral pendulum appliance, associated with fixed orthodontic appliances. The headgear group comprised 30 patients (19 females, 11 males), with an initial age of 13.07 years [standard deviation (SD) = 1.3], treated with CHG and fixed orthodontic appliances for a mean period of 3.28 years, and the pendulum group 22 patients (15 females, 7 males), with initial age of 13.75 years (SD = 1.86), treated with the pendulum appliance followed by fixed orthodontic appliances for a mean period of 4.12 years. Lateral cephalograms were taken at the start (T1) and on completion (T2) of orthodontic treatment. The pendulum and CHG groups were similar as to initial age, severity of the Class II malocclusion, gender distribution, initial cephalometric characteristics, and initial and final treatment priority index (TPI). Only treatment time was not similar between the groups, with a need for annualization for data for the pendulum group. The data were compared with independent t-tests. There was significantly greater restriction of maxillary forward growth and improvement of the skeletal maxillomandibular relationship in the CHG group (P < 0.05). The maxillary molars were more mesially tipped and extruded and the mandibular molars more uprighted in the CHG group compared with the pendulum group (P < 0.05). There was more labial tipping of the mandibular incisors and greater overbite reduction in the pendulum group. The pendulum appliance produced only dentoalveolar effects, different from the CHG appliance, which restricted maxillary forward displacement, thus improving the skeletal maxillomandibular relationship.

Dental Side Effects of Mandibular Advancement Appliances – A 2-year Follow-up

Mandibular advancement appliances are employed in treating snoring and various forms of obstructive sleep apnea syndrome (OSAS). The splints facilitate the displacement of the mandible anteriorly and widens the pharyngeal lumen during sleep. Two-splint systems are anchored on the dental arches in the maxilla and mandible. The resulting reciprocal forces are transferred onto the teeth, leading to dental side effects when used long-term. We retrospectively examined the dental changes that occurred after patients had worn the Thornton Adjustable Positioner (TAP) for over two years. We enrolled all patients consecutively in whom the diagnosis of OSAS was made following polysomnography in a sleep laboratory between January 2004 and December 2005 and who had been treated primarily with a TAP. We compared the patients' baseline findings with follow-up findings after more than 24 months of continuous appliance wear. 24/47 of the patients were still wearing the splints regularly after an average of 33 +/- 9.1 months. Overbite was highly significantly reduced (p = 0.006). We noted a reduction in the frontal overbite of more than 1 mm in ten patients (47.6%), and the overbite of one patient decreased by 4 mm. The maxillary front teeth showed significant palatal tipping and those in the mandible significant labial tipping. Clinically small but statistically significant dental side effects predominantly affecting the incisors' inclination occur after long-term wear of a TAP appliance. The clinical relevance of these dental changes to the patient can only be judged individually within the scope of an entire assessment.

Cephalometric evaluation of Class II malocclusion treatment with cervical headgear and mandibular fixed appliances

The present study aimed to evaluate the cephalometric changes in Class II patients treated exclusively with cervical headgear (CHG) in the maxillary arch and fixed appliances in the mandibular arch as compared with a control group. The sample comprised 82 lateral cephalograms obtained pre- (T1) and post- (T2) treatment/observation of 41 subjects, divided into two groups: group 1-25 Class II division 1 patients (20 females and five males), with a mean pre-treatment age of 10.4 years, treated for a mean period of 2.5 years and group 2-16 Class II untreated subjects (12 females and four males), with a mean initial age of 9.9 years, followed for a mean period of 2.2 years. Treatment changes between the groups were compared by means of t-tests. The results showed restriction of maxillary forward displacement and also a restriction in maxillary length growth, improvement in the maxillomandibular relationship, restriction of mandibular incisor vertical development, reduction in overjet and overbite, and improvement in molar relationship. It was concluded that this treatment protocol corrected the Class II malocclusion characteristics primarily through maxillary forward growth restriction.

Effects of Cervical Headgear on Overbite against the Background of Existing Growth Patterns

To test the questions "Does cervical headgear treatment necessarily lead to a reduction of overbite?" and "Are there differences in treatment results due to different growth patterns or the initial overbite?" Initial and intermediary casts of 247 patients who had been treated exclusively with headgear were analyzed for changes in the occlusal relationship of the first molars and overbite. Orthodontic treatment consisted of the application of cervical headgear with nonangulated external arms applied at a force of 3.5-4.0 N. Only patients showing dental changes of occlusal relationship > or = 4 mm during at least a 6-month treatment duration were selected. Growth patterns were identified by the y-axis values measured on lateral cephalograms obtained at study entry. Six groups were formed on the basis of these growth patterns. Headgear treatment induced bite deepening in patients with vertical growth patterns and bite opening in patients with horizontal growth patterns. Further subdivision based on initial overbite revealed bite deepening in patients with small initial overbite and bite opening in patients with large initial overbite. These differences were statistically significant (P < .05). Only minor changes were observed in patients with an initial overbite of 3-4 mm. Overbite reductions were not dependent on the growth pattern. Orthodontists should expect bite opening in deep-bite situations and bite deepening in open-bite situations. However, initial overbite situations of 3-4 mm should not be expected to change in a significant way.

Predictors of long-term orthodontic side effects from mandibular advancement devices in patients with snoring and obstructive sleep apnea

Orthodontic side effects can complicate the long-term use of mandibular advancement devices (MADs) in the treatment of patients with snoring and obstructive sleep apnea. The aim of this study was to find predictors of dental side effects from monoblock MADs. Four hundred fifty patients, who consecutively received treatment with either soft elastomeric or hard acrylic devices, were followed up after 5.4 +/- 0.8 years (mean +/- SD). The continuing patients responded to questionnaires and had dental examinations and plaster casts made. Twenty-seven patients had moved or died during the follow-up period. Two hundred thirty-six of the remaining 423 patients (56%) continued treatment, and 187 of them reported compliance rates of > or = 50% at night. A small reduction in overjet of < 1 mm was associated with a deepbite with an overbite of > 3 mm and an overjet of < or = 3 mm (odds ratio [OR] = 7.5; P = .015), nasal congestion (OR = 2.9; P = .005), or the use of a soft elastomeric device (OR = 2.7; P = .014) controlled for age, sex, treatment time, and mandibular displacement. A small reduction in overbite of < 1 mm was related to a small opening of the mandible of < 11 mm (OR = 2.5; P = .008). Orthodontic side effects might be predictable on the basis of initial characteristics in dental occlusion and the design of MADs.

The overbite and intraoral mandibular distraction osteogenesis

Purpose: The purpose of this study was to quantify the overbite reduction in skeletal Angle Class II malocclusions and discuss the management of the overbite during and after intraoral distraction of the mandible, and during orthodontic treatment with fixed appliances. Material and Methods: Cephalograms of 26 patients with an Angle Class II malocclusion and orthodontic appliances and distraction osteogenesis of the horizontal part of the mandible before (T0) and at least 1 year after treatment (T1) were evaluated. Mean age of the patients at the time of distraction was 14.6 years (range 12.8–15.9 years) and at the final registration 17.3 years (range 14.6–20.4 years). Results: The overbite decreased significantly and the SpP/MP value increased significantly. The increase in the value of the Y-axis and the MP/SN angle before and after treatment was statistically insignificant. Conclusion: Opening of the bite during distraction of the mandible can be expected. The use of the ‘floating bone’ technique did not correct the overbite permanently. The patients in whom an open bite has already been treated are not ideal for mandibular lengthening by means of distraction osteogenesis.

Growth and treatment changes in patients treated with a headgear-activator appliance

The aim of this study was to investigate growth and treatment changes in patients with Class II Division 1 malocclusion treated with a combined headgear-activator appliance. The sample consisted of 20 consecutive male patients treated with headgear-activator. Their compliance was checked after 2 months of treatment, and 3 patients dropped out. Lateral cephalograms, obtained 6 months before treatment, at the start of treatment, after 6 and 12 months of treatment, and 24 months after treatment, were analyzed by the method of Pancherz. The results disclosed that during growth, on average, overjet, molar relationship, and jaw-base relationship improved, and the mandibular incisors became retruded; the changes were statistically significant over a 2-year period. There was no significant change in the overbite. During the 12 months of treatment, there was no maxillary forward growth, and the jaw relationship improved (P <.001) because of forward growth of the mandible (P <.001). The molar relationship and the overbite improved (P <.001). Significant treatment effects included reduction in overjet (P <.001) and overbite (P <.01), and improvement of jaw-base (P <.05) and molar (P <.001) relationships. There was significant restraint of maxillary forward growth (P <.05). The eruption of the maxillary incisors and molars was restrained (P <.05). The average basic growth pattern in Class II Division 1 malocclusion resulted in small favorable changes in overjet, molar relationship, and jaw-base relationship. The main effect of the headgear-activator appliance was a favorable dental change, limited to restraint of maxillary forward growth but not affecting the vertical dimension. (Am J Orthod Dentofacial Orthop 2002;121:376-84)

Overbite correction and sagittal changes: late mixed-dentition treatment effects

Abstract This study involved the assessment of preand post-treatment lateral cephalograms from 182 late mixed-dentition patients with Class I and Class II malocclusions, with or without crowding, selected before treatment commenced. It was designed specifically to determine whether antero-posterior mandibular dento-alveolar and skeletal changes occurring with growth and one particular late mixed-dentition treatment approach are influenced in any way by the required amount of incisal overbite correction to be achieved with treatment. Significantly greater forward movements were found at both point B and pogonion in non-headgear patients in whom very deep overbites had been reduced, when compared with patients with less required incisal overbite reduction. This finding would seem to have provided further quantitative evidence to support the concept of unlocking of dento-alveolar structures with early reduction of very deep incisal overbites in appropriate patients. The suggestion was therefore made that the bite-opening in such deep-bite patients should be undertaken at least as early as this late mixed-dentition stage in order to provide an improved environment for the mandibular dento-alveolus as the mandible itself moves forward with normal growth.

Dental and skeletal changes associated with long-term mandibular advancement.

Little is known of the possible dental or skeletal side effects following the use of mandibular advancement in the treatment of obstructive sleep apnea. A study has subsequently been designed to investigate these issues. 100 consecutively treated medically referred patients were reviewed cephalometrically in 6-month intervals (6-30 months) following mandibular advancement therapy. Orthodontic Private Practice. 87 males, 13 females (mean age 49 years, SD 8.5, range 33-74 years). N/A. Reference points and planes in the cranial base, maxilla, and mandible were digitized with a reflex metrograph and their means converted to linear and angular measurements. Significant changes following mandibular advancement were observed in lower face height, vertical condylar position, incisor angulation, overbite, and overjet. Skeletal changes were attributed to a vertical repositioning of the mandibular condyle relative to the cranial base and were present at the first review period (6 months). Dental changes occurred later with treatment with the most significant changes occurring at the final review period (30 months) which resulted in a 4.9 degrees proclination of the mandibular incisors and a reduction in overbite of 1.82mm. The data suggests that long-term use of mandibular advancement can cause dental and skeletal changes which may be progressive over time. As many consider mandibular advancement a treatment for life, it is strongly recommended that all patients be fully informed of the potential for such changes prior to treatment and undergo mandatory dental reviews with long-term mandibular advancement.

A cephalometric evaluation of the Biobloc technique using matched normative data.

The outcome of Biobloc treatment was evaluated on 35 patients, 13 male, 22 female, with Class II, Division 1 malocclusions. Cephalometric radiographs were taken before and after treatment. A control group was generated from published normative data in such a way that each treated case was matched individually for age, sex and treatment time. The cephalometric change during treatment was compared to the natural growth change in the matched control group using a Mann-Whitney U-test. The treatment effect was calculated by subtracting the natural growth change from the treatment change. This was then compared to twice the method error to see if the treatment change was clinically significant. There was both a statistically and a clinically significant reduction in overjet (p < 0.001), overbite (p < 0.001) and angle ANB (p < 0.001) with an increase in angle SNB (p < 0.001). None of the other cephalometric parameters measured showed a significant change except for upper incisor proclination (p < 0.05) and ArGoMe angle (p < 0.05) but these were not clinically significant.

The relationship between the curve of spee,relapse, and the Alexander discipline

Exaggerated curves of Spee are frequently observed in dental malocclusionsthat present with deep vertical overbites. During orthodontic treatment such excessive curves of Spee are usually leveled and, in most instances, this leveling will result in a reduction of the anterior overbite. The Alexander Discipline provides a good example of modern straight-wire orthodontic techniques that purport an ability to treat abnormal variations in the depth of the occlusal plane. The records of 31 randomly selected patients treated by nonextraction with the Alexander Discipline were studied. The results show that the Alexander Discipline levels the curve of Spee in Class II, Division I deep-bite cases and that when relapse occurs, the curve of Spee returns to a lesser extent than was present before orthodontic treatment. With the Alexander Discipline, a pretreatment curve of Spee that is not completely level posttreatment has a slightly higher incidence and magnitude of relapse than a pretreatment curve of Spee that is completely level posttreatment. This study indicated that, based on the pretreatment curve of Spee, there is no ability to predict relapse in mandibular intercanine width, overbite, overjet, mandibular incisor irregularity, and arch length in Class II, Division I deep-bite cases treated with the Alexander Discipline.

Cephalometric evaluation of open bite treatment with NiTi arch wires and anterior elastics

The aim of this study was to evaluate cephalometrically the effects of open bite treatment with NiTi arch wires and anterior elastics. The study group comprised of 17 patients who displayed a high angle skeletal pattern, along with an anterior open bite. After initial leveling, 0.016 × 0.022 inch upper accentuated-curve and lower reverse-curve arch wires were placed, with anterior elastics applied in the canine regions. Cephalometric assessment was carried out on lateral head films taken at the beginning of treatment and on average 2.8 months after open bite closure was obtained. The results of this study indicated that open bite closure had been achieved mainly by extrusion of the lower incisors and uprighting of the upper incisors. The functional occlusal plane was leveled by extrusion of lower premolars and uprighting of lower molars. Lateral cephalograms obtained from 10 patients who had been available after 1 year postretention were used to evaluate relapse changes. During the follow-up period, position of the upper and lower incisors and the inclination of the occlusal plane were maintained. However, extrusion of upper and lower molar teeth resulted in a reduction in overbite. (Am J Orthod Dentofacial Orthop 1999;116:555-62)

Initial effects of treatment of Class II malocclusion with the Herren activator, activator-headgear combination, and Jasper Jumper

The initial effects of treatment of Class II, Division 1 malocclusion with an activator, according to Herren (27 patients), with an activator-headgear combination (20 patients), or with the Jasper Jumper appliance (25 patients) were studied on lateral cephalograms from before and after 6 to 8 months of treatment. The patients' ages ranged from 9 to 12 years. At the end of the period of observation, the correction in overjet and molar relationship was more complete in the patients with the Jasper Jumper than in the patients with the activator. Whereas all the patients with the Jasper Jumper showed neutral occlusion, this was the case in only 20 of the 47 patients with the activator. The correction of the distal occlusion occurred through a combination of skeletal and dentoalveolar adaptations. Skeletal changes accounted for 42%, 35%, and 48% of the overjet correction by the Herren-type activator, the headgear-activator, and the Jasper Jumper, respectively. The correction of the molar relationship occurred to 55%, 46%, and 38% by skeletal changes in the respective groups. Dentoalveolar compensation (distal movement of the upper molars, mesial movement of the lower molars) appeared to be inversely related to skeletal adaptation. The patients with the Jasper Jumper showed a marked intrusion of the lower incisors with a consequent reduction in overbite. (Am J Orthod Dentofac Orthop 1997;112:19-27.)

Evaluation of continuous arch and segmented arch leveling techniques in adult patients—a clinical study

The purpose of this study was to compare the efficacy of overbite correction achieved by a conventional continuous arch wire technique and the segmented arch technique as recommended by Burstone. The sample comprised 50 adult patients (age 18 to 40 years) with deep bites. Twenty-five patients were treated with a continuous arch wire technique (CAW); in the second half of the sample, the segmented arch technique (Burstone) was used for correction of the vertical malocclusion. Lateral cephalograms and plaster cast models taken before and immediately after treatment were evaluated. Statistical analysis was performed on the collected data. The results showed that both techniques produced a highly significant overbite reduction (CAW: -3.17 mm, p < 0.001; Burstone: -3.56 mm, p < 0.001). The CAW group showed an extrusion in the molar area with subsequent posterior rotation of the mandible (6occl-ML: +1.30 mm; 6occl-NSL: +1.63 mm; ML/NSL: +1.94 degrees, all p < 0.001). The Burstone group, however, showed overbite reduction by incisor intrusion without any substantial extrusion of posterior teeth (upper 1-NSL: -1.50 mm; lower 1-ML: -1.72 mm; both p < 0.001). As a consequence, no significant posterior rotation of the mandible took place (ML/NSL: +0.52 degrees, n.s.). It is concluded that in adult patients the segmented arch technique (Burstone) can be considered as being superior to a conventional continuous arch wire technique if arch leveling by incisor intrusion is indicated.

The inclined biteplane—a useful tool

A technique is described to help maintain overjet and overbite reduction achieved with a functional appliance, while waiting to proceed with definitive treatment or for use after a definitive course of fixed appliance therapy to help maintain the achieved result. (Am Orthod Dentofac Orthop 1996;110:339-50.)

Facial structure and functional findings in patients with progressive muscular dystrophy (Duchenne)

The investigation of 15 patients who have a progressive muscular dystrophy of the Duchenne type (PMD) shows the affection of various groups of muscles of the stomatognathic system, studied by means of electromyography and mechanical force measurements. We observed the following deviations in patients with PMD; transversal overdevelopment and sagittal shortening of the dental arch; reduction of overbite and overjet; sagittal underdevelopment of the cranial, maxillary and mandibular base; retrusion of incisors; concave profile; increase in bizygomatic width; and a difference in time between the attack on the musculi orbicularis oris and that on masticatory muscles. In our study, the activity of the jaw muscles diminished 2 years earlier compared with the perioral muscles. This, and also the enlargement of the hypotonic tongue, causes a transversal expansion of skull and dental arches. This expansion was strongly pronounced in the lower jaw; we invariably observed a posterior crossbite. In contrast to the transversal overdevelopment, we observed a sagittal underdevelopment of skeletal and dental parameters, as well as a retrusion of the incisors. The results of surface electromyography showed the affection of the masseter muscle in patients who had PMD. By means of the Fast-Fourier transformation, we observed a displacement of the median frequency as compared with the lower frequency range. (Am J Orthod Dentofac Orthop 1996;110:185-90.)