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Biomedical subjects

H Pancherz

Publications and source records attributed to H Pancherz.

At least 19 recordsLinked to original sources
PubMed2001

Efficiency of root torquing auxiliaries.

In an experimental typodont study simulating the third stage of Tip-Edge treatment, the effect of five torquing auxiliaries on upper four incisors was assessed using the method of laser reflection. The auxiliaries analysed were: (1) Two-Spurs 0.016", (2) Four-Spurs 0.016", (3) Reciprocal Lateral Torque 0.016", (4) Torque Bar 0.022x0.018", 20 degrees, and (5) Torque Bar 0.022x0.018, 30 degrees. When comparing the wires, the efficiency (amount and speed of root tipping) varied considerably: (1) The Two-Spurs wire was the most efficient auxiliary of the five tested and showed good torque effect on the central incisors. (2) The Four-Spurs wire acting on all four incisors was less efficient than the Two-Spurs wire. (3) The Reciprocal Lateral Torque wire exhibited good palatal root torque on the central incisors and labial root torque on the lateral incisors. (4) The Torque Bars (20 degrees and 30 degrees ) were the least efficient wires of the auxiliaries tested and showed only small torque effects on the central and lateral incisor teeth. In clinical work using the Tip-Edge technique, the Two-Spurs torquing auxiliary should be the wire of choice for an efficient palatal root torque of the upper central incisors.

Journal Article↗
PubMed2001

Effective condylar growth and chin position changes in activator treatment: a cephalometric roentgenographic study.

Effective condylar growth (a summation of condylar remodeling, glenoid fossa remodeling, and condylar position changes within the fossa) and its influence on the position of the chin was analyzed in 40 class II, division I malocclusions treated successfully with activators. Additionally, the amount of mandibular rotation was assessed. Lateral head films in habitual occlusion from before and after an average treatment period of 2.6 years were evaluated. The Bolton Standards (32 untreated individuals with ideal occlusion) served as controls. Two different treatment effects were evaluated: overall growth change and treatment effects (overall growth changes minus age-related Bolton values). In comparison with the Bolton group, the activator patients exhibited an increase in the amount of vertical effective condylar growth (3.0 mm; P < .001), a decrease in the amount of sagittal effective condylar growth (0.6 mm; P < .05), and an increase in the amount of vertical development of the chin (1.8 mm; P < .001). No group differences could be found for sagittal development of the chin. In the Bolton group, the mandible rotated posteriorly, and in the activator group it rotated anteriorly (2.7 degrees; P < .001). The present investigation revealed that effective condylar growth can be increased and the chin position can be changed by activator treatment. Thus activator treatment induces skeletal changes, although not always in the desired (sagittal) therapeutic direction.

Activator Appliances↗
PubMed2001

Skeletal changes of Herbst appliance therapy investigated with more conventional cephalometrics and European norms.

We measured the skeletal effects of Herbst appliance treatment in a retrospective sample of 25 boys (aged 10.7-14.5 years) and 25 girls (aged 10.7-14.3 years). Selection criteria were (1) a pretreatment full Class II molar relationship (ANB angle: average, 6.7 degrees; range, 2.5-10.5 degrees) and (2) a posttreatment full Class I or overcorrected Class I molar relationship within 6-8 months. A first t-test was used to evaluate variations between pre- and posttreatment cephalometric measures. Then, compared with the appropriate age- and sex-matched European norm, every pre- and posttreatment value was transformed into a z-score on the distribution of the norm value and a second t-test was performed. The second t-test was to study variations between pre- and posttreatment z-scores in order to neutralize the effect of natural growth. Posttreatment, the mandible showed a remarkable forward repositioning without opening of the gonial angle, particularly in males. Only ANB and Xi-CF-PTV angles were significantly different when the effect of normal growth was excluded. In males, ramus height and mandibular basal length were significantly increased when total variation was considered (ie, not excluding the effect of normal growth). In females, only the mandibular ramus height was significantly increased. In conclusion, even short-term Herbst therapy can be efficacious, with the most frequent effect being mandibular forward repositioning followed by mandibular ramus elongation. The statistical procedure used counteracts the effect of growth and sex on the results. Moreover, z-scores are adimensional measures with which any kind of parameter may be compared and scaled to each other in the perspective of a more reliable mutivariated interpretation of cephalometric variables.

Adolescent↗
PubMed2001

The incisor-lip relationship in Herbst/multibracket appliance treatment of Class II, Division 2 malocclusions.

The purpose of this investigation was to examine the effect of Herbst/multibracket appliance treatment on the upper incisor-lower lip relationship in the management of Class II, division 2 malocclusions. The study evaluated 19 successfully treated subjects using lateral head films analyzed at 3 occasions: before (T1) and after (T2) Herbst/multibracket appliance treatment and 1-year posttreatment (T3). The average treatment (T1-T2) changes showed (1) the lower lip overlap on the upper incisors was reduced from 6.0 mm to 4.2 mm (P < .001), (2) the upper incisors were proclined 15.3 degrees (P < .001) and the lower incisors were proclined 9.6 degrees (P < .001), (3) the overbite was reduced from 7.3 mm to 1.7 mm (P < .001), and (4) the sagittal jaw base relationship (Wits) improved from +3.5 to +0.5 mm (P < .001). The average posttreatment (T2-T3) changes showed (1) the upper incisor-lower lip relationship remained stable, (2) the upper (0.6 degrees; P < .001) and lower (2.3 degrees; P < .001) incisors retroclined, (3) the overbite increased (1.2 mm; P < .001), and (4) the sagittal jaw base relationship remained unchanged. In conclusion, it was found that the upper incisor-lower lip relationship was improved by Herbst/multibracket appliance treatment and remained stable during a 1-year posttreatment period in spite of minor relapses of incisor tooth positions and relationships.

Cephalometry↗
PubMed2000

Does bite-jumping damage the TMJ? A prospective longitudinal clinical and MRI study of Herbst patients.

The aim of this prospective longitudinal study of 62 consecutively treated Class II malocclusions was to determine whether bite-jumping causes temporomandibular disorders (TMD). The function of the temporomandibular joint (TMJ) was assessed anamnestically, clinically, and by means of magnetic resonance images (MRIs) taken before (T1), after (T2), and 1 year after (T3) Herbst treatment. Average treatment time with the Herbst appliance was 7.2 months. In all subjects, Herbst treatment resulted in a Class I or overcorrected Class I dental arch relationship. Thereafter, treatment was continued with a multibracket appliance. The condyle was positioned significantly forward during treatment but returned to its original position after removal of the Herbst appliance. A temporary capsulitis of the inferior stratum of the posterior attachment was induced during treatment. Over the entire observation period from before treatment to 1 year after treatment, bite-jumping with the Herbst appliance: (1) did not result in any muscular TMD; (2) reduced the prevalence of capsulitis and structural condylar bony changes; (3) did not induce disc displacement in subjects with a physiologic pretreatment disc position; (4) resulted in a stable repositioning of the disc in subjects with a pretreatment partial disc displacement with reduction; and (5) could not recapture the disc in subjects with a pretreatment total disc displacement with or without reduction. A pretreatment total disc displacement with or without reduction did not, however, seem to be a contraindication for Herbst treatment. In conclusion, bite-jumping using the Herbst appliance does not have a deleterious effect on TMJ function and does not induce TMD on a short-term basis.

Adolescent↗
PubMed1999

Individual-based prediction of the size of the supporting zones in the permanent dentition. A comparison of the Moyers method with a unitary prediction value.

The aims of this individual-based study were 1. to assess the actual space requirements of the permanent canines and premolars, 2. to test the reliability of the Moyers method in predicting a space deficiency at the 75% confidence level and 3. to try to find a reliable unitary prediction value (= unitary value) as a possible substitute for the calculated Moyers values. Dental cast measurements were taken of the permanent dentition of 100 females and 100 males. The average sum of the widths of the maxillary and mandibular permanent canines and premolars was 20.8 mm (17.3 to 24.3 mm). The Moyers method could predict a maxillary space deficiency in 77.5% and a mandibular space deficiency in 65.5% of the subjects. The unitary value of 22.0 mm made it possible to predict a space deficiency in 83.5% of the subjects. The unitary value thus had a higher confidence level (83.5%) than the 75% level stated by Moyers and might thus substitute the calculated Moyers values. Furthermore, the unitary value is easy and quick to handle.

Bicuspid↗
PubMed1999

Electromyography of the perioral and masticatory muscles in orthodontic patients with atypical swallowing.

Subjects with an open bite and an atypical swallowing pattern before (n = 20) and after (n = 10) orthodontic treatment and subjects with a normal swallowing pattern (n = 15) were examined. The electromyographic (EMG) activity of the upper and lower lips in the region of the modiolus and of the mentalis, masseter and temporal muscles was evaluated during the swallowing of saliva and of water and after the chewing of peanuts as well as during maximal biting in intercuspal position. During swallowing the atypical swallowers exhibited larger EMG activities of the perioral muscles and smaller EMG activities of the masticatory muscles than the control subjects. During maximal biting in intercuspal position, major EMG activity of the masseter and temporal muscles and minor EMG activity of the perioral muscles were recorded in both groups. No normalization of the electromyographic swallowing pattern could be observed during orthodontic treatment (closure of the open bite).

Adolescent↗
PubMed1999

Mandibular articular disk position changes during Herbst treatment: a prospective longitudinal MRI study.

The aim of this prospective longitudinal study of 15 consecutively treated Class II malocclusions was to assess any possible changes in the relative position of the articular disk to the condyle during different phases of Herbst therapy. Using a disk position index, parasagittal MRIs (central, medial and lateral slices) of the right and left TMJ were analyzed at five occasions: before Herbst treatment (T1), at start of treatment when the appliance was placed (T2), after 6 weeks of treatment (T3), after 13 weeks of treatment (T4), and after 7 months of treatment when the appliance was removed (T5). In all subjects Herbst treatment resulted in Class I or overcorrected Class I dental arch relationships. Condyle position was on average unchanged during Herbst treatment (T1 to T5). Before treatment (T1) the articular disk was in a slight protrusive position relative to the condyle. At start of treatment (T2) the mandible was advanced to an incisal edge to edge position. Because of the physiologic relative movement of disk and condyle on mandibular protrusion the disk attained a pronounced retrusive position. At the end of treatment (T5), the disk had almost returned to its original pretreatment position. In several cases, however, a slight retrusive disk position prevailed. In conclusion, Herbst treatment did not result in any adverse changes in articular disk position. On the contrary, the Herbst appliance could possibly be useful in the therapy of patients with anterior disk displacement.

Adolescent↗
PubMed1999

Temporomandibular joint remodeling in adolescents and young adults during Herbst treatment: A prospective longitudinal magnetic resonance imaging and cephalometric radiographic investigation.

The aim of this prospective study was to analyze and compare the temporomandibular joint adaptive mechanisms in 25 adolescent and 14 young adult Class II malocclusions treated with the Herbst appliance. Temporomandibular joint remodeling was analyzed by magnetic resonance imaging. In each subject, 4 magnetic resonance images of both temporomandibular joints were available: before treatment, at the start of treatment (when the Herbst appliance was placed), during treatment (6 to 12 weeks after appliance placement), and after treatment (when the appliance was removed). Furthermore, effective temporomandibular joint changes (the sum of condylar remodeling, fossa remodeling, and condyle-fossa relationship changes) were analyzed with the aid of lateral cephalometric radiographs from before and after treatment. All subjects were treated to Class I or overcorrected Class I dental arch relationships, and their mandibles became significantly (P <.001) more prognathic. After 6 to 12 weeks of Herbst treatment, signs of condylar remodeling were seen at the posterosuperior border in 48 of the 50 adolescent condyles and in 26 of the 28 young adult condyles. Bilateral remodeling of the mandibular ramus could be detected in 1 adolescent and 2 young adult patients. Signs of glenoid fossa remodeling at the anterior surface of the postglenoid spine were noted in 36 adolescent and 22 young adult temporomandibular joints. Effective temporomandibular joint changes during treatment were more horizontally directed and larger in both adolescents and young adult patients treated with the Herbst appliance than in an untreated group of subjects with ideal occlusion (Bolton standards). The increase in mandibular prognathism accomplished by Herbst therapy in both adolescents and young adults seems, in particular, to be a result of condylar and glenoid fossa remodeling. Because the Herbst appliance is most successful in Class II patients also at the end of the growth period, the treatment method could be an alternative to orthognathic surgery in borderline skeletal Class II cases. Magnetic resonance imaging renders an excellent opportunity to visualize the temporomandibular joint remodeling growth processes.

Adaptation, Physiological↗
PubMed1999

The compensatory mechanism in high-angle malocclusions: a comparison of subjects in the mixed and permanent dentition.

Dentoskeletal morphology was assessed in 191 untreated and unselected children with a hyperdivergent (high-angle) mandibular plane (ML/NSL > or =40 degrees) by analyzing lateral roentgenographic cephalograms. The subjects were divided into mixed dentition and permanent dentition groups, and further divided into subgroups based on the amount of overbite (OB) as a measure of dentoalveolar compensation of jaw base hyperdivergency: OB < 0 mm (openbite) = insufficient/no compensation; OB 0 to 4 mm (normal overbite) = acceptable compensation; OB > 4 mm (deepbite) = overcompensation. Openbite was observed in 20% of the children, normal overbite in 50%, and deepbite in 30%. Skeletally, the deepbite mixed dentition group was characterized by a relatively posterior inclination of the maxilla, while the deepbite permanent dentition group had a relatively anterior inclination of the mandible. Dentoalveolar compensation was accomplished by relative increases in maxillary and mandibular anterior dentoalveolar heights in the mixed dentition group and by relative decreases in maxillary and mandibular posterior dentoalveolar heights in the permanent dentition. Positive overbite was found in the majority (80%) of children with high-angle morphology. Thus, mandibular hyperdivergency is frequently compensated for. Skeletal characteristics and dentoalveolar compensatory mechanisms differ with dental maturity and seem to be influenced by mouth breathing and other oral habits.

Age Factors↗
PubMed1999

Dentoskeletal effects and facial profile changes in young adults treated with the Herbst appliance.

This prospective Herbst study analyzed the sagittal dental and skeletal changes contributing to Class II correction in young adults. Additionally, the alteration in skeletal and soft tissue convexity occurring during treatment was assessed. Early adolescent subjects in the permanent dentition who had been treated with the Herbst appliance were used for comparison. Lateral headfilms from before and after an average treatment period of 8.5 months for the young adults and 7.1 months for the adolescents were evaluated. All adult and adolescent subjects were treated to either Class I or overcorrected Class I occlusal relationships. In both groups the improvement in sagittal incisor and molar relationships was achieved more by dental changes than by skeletal ones. The amount of skeletal change contributing to overjet and molar correction was smaller in the young adult group (22% and 25%, respectively) than in the early adolescent group (39% and 41%, respectively). Skeletal and soft tissue facial profile convexity was reduced in adults and adolescents. Facial profile improvement did not differ between the two groups. The results of this study revealed that the Herbst appliance is most effective in the treatment of Class II malocclusion in young adults. It is suggested that this treatment method could be an alternative to orthognathic surgery in borderline Class II cases.

Adolescent↗
PubMed1999

Orthodontic treatment of openbite and deepbite high-angle malocclusions.

The aim of the investigation was to assess the effect of orthodontic treatment on dentoskeletal morphology in children with openbite and deepbite high-angle malocclusion. Subjects (n = 54) in the mixed dentition with a hyperdivergent mandibular plane angle (high-angle, NSL/ML > or =40 degrees) were surveyed. Pre- and posttreatment lateral roentgenographic cephalograms were analyzed. Subjects were divided into three subgroups according to the amount of pretreatment overbite: < 0 mm = insufficient/no compensation (openbite); 0-4 mm = acceptable compensation (normal overbite); >4 mm = overcompensation (deepbite). Pretreatment, 20% of the high-angle cases exhibited insufficient dentoskeletal compensation (overbite <0 mm), and 35% displayed overcompensation (overbite >4 mm). Influences of habits such as lip sucking and tongue-thrust swallowing were more common in the openbite group. No major difference in treatment approach could be found between subgroups. In 82% of the openbite group and 90% of the deepbite group, overbite was corrected by orthodontic treatment. The mandibular plane angle was unaffected in both groups. The mechanisms of overbite correction differed between groups. The openbite group exhibited a significant decrease in interjaw-base angle. Increases in anterior and posterior dentoalveolar heights were comparable. The deepbite group showed no significant changes in skeletal morphology. The increase in dentoalveolar height was approximately twice as large posteriorly as anteriorly. The majority of children (80%) with high-angle morphology had a positive pretreatment overbite, thus exhibiting compensation of jaw-base hyperdivergency. Orthodontic treatment of high-angle malocclusions did not influence the mandibular plane angle in openbite or deepbite cases. Overbite correction was accomplished by tipping the maxilla downward anteriorly in openbite subjects, and by controlling incisor eruption in deepbite subjects.

Cephalometry↗
PubMed1998

Dentoskeletal morphology in children with Deckbiss.

A comparison of dentoskeletal morphology in 176 Deckbiss malocclusions with Class I molar relationship (Class I/2) and 156 Deckbiss malocclusions with Class II molar relationship (Class II/2) was performed using lateral cephalometric radiographs. Children at the ages of 8 to 10 years and 11 to 13 years were evaluated. The results of the study revealed broad variations in the variables analysed. A relatively short lower face and an obtuse interincisal angle were the only consistent features of the Deckbiss (Class I/2 and Class II/2). Otherwise the dentoskeletal morphology of the Deckbiss was untypical. When comparing the Class I/2 and Class II/2 samples the following morphological traits were more pronounced and/or more frequent in the Class II/2 sample: 1. mandibular retrusion, 2. skeletal Class II jaw base relationship, 3. mandibular plane angle reduction, 4. jaw base hypodivergency, and 5. upper incisor retroclination. Lower incisor retroclination, on the other hand, was more pronounced and more frequent in the Class I/2 sample. Age affected exclusively the Class I/2 sample: maxillary and mandibular retrusion were seen more frequently in the younger than in the older subjects.

Adolescent↗
PubMed1998

Long-term TMJ effects of Herbst treatment: a clinical and MRI study.

The long-term effects of the Herbst appliance on the temporomandibular joint were assessed in 20 patients (10 girls and 10 boys) who had completed treatment an average of 4 years previously. The TMJ analysis comprised of: (1) an anamnestic questionnaire (2) a clinical investigation (manual functional analysis) and (3) magnetic resonance imaging of the left and right joints. The results revealed that the incidence of anamnestic and clinical signs and symptoms of temporomandibular disorders was within the range of "normal" reported in the literature. The frequency of disk displacement was not higher than in asymptomatic populations. When summarizing the anamnestic, clinical and magnetic resonance imaging findings five subjects (25%) exhibited moderate to severe signs of temporomandibular disorders ranging from partial to total disk displacement or "deviation in form" of the condyle. Another three subjects (15%) showed mild symptoms of temporomandibular disorders with either small condylar displacement or subclinical soft tissue lesion. In conclusion, it can be said that Herbst treatment does not seem to have an adverse long-term effect on the temporomandibular joint.

Adolescent↗
PubMed1998

"Effective condylar growth" and chin position changes in Herbst treatment: a cephalometric roentgenographic long-term study.

In 98 Class II Division 1 malocclusions treated with the Herbst appliance "effective condylar growth" (a summation of condylar remodeling, glenoid fossa remodeling, and condylar position changes within the fossa) and its influence on the position of the chin was analyzed. Lateral head films in habitual occlusion from before and after 0.6 years of Herbst treatment as well as 0.6 years and 3.1 years posttreatment were evaluated. All patients were treated to Class I or overcorrected Class I dental arch relationships. During the treatment period, effective condylar growth was relatively more backward directed and about three times larger than that in untreated subjects with ideal occlusion (Bolton Standards). During the first posttreatment period of 0.6 years, effective condylar growth recovered with respect to both the direction and amount of changes. During the second posttreatment period of 2.5 years, effective condylar growth was "normal." The corresponding chin position changes during the different examination periods were a mirror image of effective condylar growth provided no mandibular autorotation occurred. In cases with anterior mandibular autorotation, relatively more forward and in cases with posterior mandibular autorotation relatively more backward directed chin position changes resulted.

Adolescent↗
PubMed1998

Does orthodontic proclination of lower incisors in children and adolescents cause gingival recession?

In this investigation we sought to assess the effect of orthodontic proclination of lower incisors in children and adolescents with respect to the possible development of gingival recession. Ninety-eight children with a mean +/- SD start-of-treatment age of 12.8 +/- 1.4 years, treated with the Herbst appliance, were surveyed, for a total of 392 lower incisors. Lateral head films, dental casts and intraoral photographs were analyzed with respect to the degree of orthodontic proclination, crown height, and gingival recession. In all subjects, Herbst treatment resulted in varying degrees of lower-incisor proclination (mean = 8.9 degrees, range = 0.5 degrees to 19.5 degrees). In 380 of the surveyed teeth (97%), either no recession developed or preexisting recession remained unchanged during Herbst therapy. In only 12 teeth (3%) did recession develop or preexisting recession deteriorate during treatment. No interrelation was found between the amount of incisor proclination and the development of gingival recession. In conclusion, orthodontic proclination of lower incisors in children and adolescents seems not to result in gingival recession.

Adolescent↗