Treatment of Class II, Division 2 in the late growth period

The "Deckbiss" with skeletal Class II jaw relationship sometimes presents a considerable therapeutic problem, particularly in the late growth period (DP3U), as regards the coordination of dental and skeletal treatment objectives. An effective treatment approach was demonstrated: a modified Herbst appliance used simultaneously with fixed appliances in the maxilla. The sample comprised 12 male (14.0 +/- 0.9 years old) and 10 female (12.3 +/- 0.4 years old) patients. Correction of the distal occlusion was achieved in all patients by means of the Herbst appliance, which was removed after an average time period of 6.4 +/- 0.2 months. In the mandible the multibracket appliances were then immediately inserted, and Class II elastics were used for retention. Maximum anchorage was required in the maxilla as well as in the mandible. Complete diagnostic records were made at the beginning of the treatment as well as 6 and 12 months later, in order to document skeletal and dental changes. A dental and skeletal Class I relationship was achieved in all cases. A significant improvement was recorded in the vertical jaw base relationship; this was still stable after a period of 12 months. In the dental area in particular, a so-called high-pull headgear effect (intrusion and distalization 16, 26) and intrusion of teeth 34, 44 were registered. Only a minor protrusion of the mandibular incisors was observed. Reinforcement of the bands reduced the failure rate significantly. The Herbst appliance does not represent a standard treatment for Class II. Its indication range is limited.     

Treatment response to maxillary expansion and protraction

A prospective clinical trial was conducted to determine the skeletal and dental contributions to the correction of overjet and overbite in Class III patients. Thirty patients (12 males and 18 females with a mean age of 8.4 +/- 1.7 years) were treated consecutively with protraction headgear and fixed maxillary expansion appliances. For each patient, a lateral cephalogram was taken 6 months before treatment (T0); immediately before treatment (T1); and 6 months after treatment (T2). The time period (T1-T0) represented changes due to 6 months of growth without treatment; (T2-T1) represented 6 months of growth and treatment. Each patient served as his/her own control. Cephalometric analysis described by Bj?rk (1947) and Pancherz (1982a,b) was used. Sagittal and vertical measurements were made along the occlusal plane (OLs) and the occlusal plane perpendicular (OLp), and superimposed on the mid-sagittal cranial structure. The results revealed the following: with 6 months of treatment, all subjects were treated to Class I or overcorrected to Class I or Class II dental arch relationships. Overjet and sagittal molar relationships improved by an average of 6.2 and 4.5 mm, respectively. This was a result of 1.8 mm of forward maxillary growth, a 2.5-mm of backward movement of the mandible, a 1.7-mm of labial movement of maxillary incisors, a 0.2-mm of lingual movement of mandibular incisors, and a 0.2-mm of greater mesial movement of maxillary than mandibular molars. The mean overbite reduction was 2.6 mm. Maxillary and mandibular molars were erupted occlusally by 0.9 and 1.4 mm, respectively. The mandibular plane angle was increased by 1.5 degrees and the lower facial height by 2.9 mm. Individual variations in response to maxillary protraction was large for most of the parameters tested. Significant differences in treatment changes between male and female subjects were found only in the vertical eruption of mandibular incisors and maxillary and mandibular molars. These results demonstrate that significant overjet and overbite corrections can be obtained with 6 months of maxillary protraction in combination with a fixed expansion appliance.     

A growth control approach to Class II, Division 1 cases during puberty involving the simultaneous application of maxillary growth restriction and mandibular forward induction

A simple method that used headgear and a functional appliance simultaneously was used for the correction of Class II, Division 1 cases with severe denture base discrepancy. The treatment restricted the forward growth of the maxilla and advanced the mandible. The functional appliance, referred to as the mandibular growth advancer (MGA), advances the mandible progressively with a splint, with the objective of remodeling the condyle and the glenoid fossa in the temporomandibular joint. Functional adaptation was achieved as the muscles that are attached to the mandible adjusted to new positions. In the two cases that illustrate this method, the ANB angle decreased and the Ar-B distance increased over a short period to four and six times the mean Japanese growth rate, respectively. After the correction of the denture-base discrepancy, a multibracket fixed appliance was used for dental alignment, and good skeletal, occlusal relationships and profiles were obtained. Treatment of severe denture-base discrepancy in this manner may reduce the skeletal abnormality, decrease the number of extraction cases, and shorten the subsequent multibracket treatment time. And it may reduce the iatrogenic side effects caused by prolonged mechanotherapy with a fixed appliance.     

Long-term effects of the Herbst appliance on the dental arches and arch relationships: a biometric study

The purpose of this study was to evaluate biometrically the treatment and post-treatment effects of the Herbst appliance on the dental arches and arch relationships. The sample consisted of 53 Class II, division 1 malocclusion patients (33 boys and 20 girls) treated with the Herbst appliance. The mean age of the patients before treatment was 12.5 years (SD = 1.2 years). Dental casts were analysed before treatment, after treatment, 6 months post-treatment and at the end of the growth period (5-10 years post-treatment). The following variables were assessed: sagittal molar and canine relationships, overjet, overbite, maxillary and mandibular arch perimeters, and inter-molar and inter-canine dental arch widths. During treatment, the overjet, overbite, and sagittal molar relationship were overcorrected in most of the cases, while the sagittal canine relationship was normalized. The maxillary and mandibular arch perimeters increased during treatment, as did dental arch widths (molar and canine). In the long-term (mean = 6.7 years after treatment), Herbst appliance treatment resulted in a normal or over-corrected sagittal molar relationship in 79 per cent and a normal canine relationship in 68 per cent of the cases. Eighty-three per cent of the subjects had an overjet of 4.5 mm or less. In the long-term, the arch perimeters seemed to follow a normal dental development pattern. The increase of the upper molar and canine dental arch widths during treatment remained virtually stable whilst the lower intermolar arch widths seemed unaffected by treatment.     

Longitudinal evaluation of growth changes in Class II division 1 subjects

Longitudinal records from the Ohio State University Growth Study were used to compare the skeletal growth changes between Class II division 1 and Class I female subjects between ages 7 and 14. Tensor analysis was used to determine the yearly growth rate and direction. No significant difference was found in cranial base dimension between the Class I and Class II subjects. In Class II subjects, the maxilla (S-N-A) was found to be normally related to the cranial base. However, mandibular position (S-N-B and S-N-Pog) was found to be significantly more retrusive in Class II when compared with Class I subjects. Mandibular length (Ar-Gn) and corpus length (Go-Gn) were found to be shorter in Class II subjects. The ratio of PFH to AFH was found to be smaller in Class II subjects. This is particularly apparent during the pubertal growth period. The y-axis and mandibular plane angle were more open in Class II subjects which also contributed to the retrusive position of the mandible. Maxillo-mandibular difference (A-N-B) between Class I and II subjects was present at age 7 and persisted through puberty, maintaining a greater angle of convexity (A-N-Pg) in Class II subjects. These results suggest that Class II malocclusion can be detected early. The majority of the Class II cases showed mandibular skeletal retrusion or a combination of horizontal and vertical abnormalities of the mandible rather than maxillary protrusion. These skeletal differences remain through puberty without orthodontic intervention. Individual variations were found within each type of malocclusion.     

Gene expression of trehalase during post-dormant development of the brine shrimp, Artemia: comparison of the two species

The purpose of this article is to summarize the short-term and long-term results of the authors' clinical prospective study on the treatment of Class III malocclusion using the protraction facemask. An attempt is made to answer questions pertaining to this treatment modality. Twenty patients with skeletal Class III malocclusion were treated consecutively with maxillary expansion and a protraction facemask. A positive overjet was obtained in all cases after 6 to 9 months of treatment. These changes were contributed to by a forward movement of the maxilla, backward and downward rotation of the mandible, proclination of the maxillary incisors, and retroclination of the mandibular incisors. The molar relationship was overcorrected to Class I or Class II dental arch relationship. The overbite was reduced with a significant increase in lower facial height. The treatment was found to be stable 2 years after removal of the appliances. At the end of the 4-year observation period, 15 of the 20 patients maintained a positive overjet or an end-to-end incisal relationship. Patients who reverted back to a negative overjet were found to have excess horizontal mandibular growth that was not compensated by proclination of the maxillary incisors. A review of the literature showed that maxillary expansion in conjunction with protraction produced greater forward movement of the maxilla. Maxillary protraction with a 30 degrees forward and downward force applied at the canine region produced an acceptable clinical response. The reciprocal force from maxillary protraction transmitted to the temporomandibular joint did not increase masticatory muscle pain or activity. Significant soft tissue profile change can be expected with maxillary protraction including straightening of the facial profile and better lip competence and posture. However, one should anticipate individual variations in treatment response and subsequent growth changes. Treatment with the protraction facemask is most effective in Class III patients with a retrusive maxilla and a hypodivergent growth pattern. Treatment initiated at the time of initial eruption of the upper central incisors helps to maintain the anterior occlusion after treatment.     

A prospective evaluation of Bass, Bionator and Twin Block appliances. Part I--The hard tissues

A prospective clinical study with a random allocation of 47 adolescent patients to three different functional appliance groups was established and compared with an untreated control group over a 9-month period. Treatment was undertaken with either a Bionator, Twin Block, or Bass appliance. Pre- and post-treatment cephalograms were used to quantify the skeletal and dentoalveolar changes produced by the appliances and compared with those observed in the control group as a result of growth. Both the Bionator and Twin Block appliances demonstrated a statistically significant increase in mandibular length (3.9 +/- 2.7 mm; 3.7 +/- 2.1 mm, respectively) compared with the control group (P < 0.05), with an anterior movement of pogonion and point B. Highly statistically significant increases (P < 0.01) were seen in lower face heights for all the appliance groups compared with the control group. The Twin Block group showed the least forward movement of point A due to a change in the inclination of the maxillary plane. The Bionator and Twin Block groups showed statistically significant reductions in the inclination of the upper incisors to the maxillary plane (P < 0.05). The Bass group showed minimal change in the inclination of the lower labial segment to the mandibular plane. The Bionator group demonstrated the greatest proclination of the lower labial segment (4.0 +/- 3.6 degrees). Clinically important changes were measured in all the appliance groups when compared with the control group. Differences were also identified between the functional appliance groups. The Twin Block appliance and, to a lesser extent, the Bionator appeared the most effective in producing sagittal and vertical changes.     

Dietary factors and risk of lung cancer in never-smokers

The primary purpose of this study was to evaluate the effectiveness of cortical anchorage, by comparing two groups of patients with Class II malocclusions that were treated successfully with Class II elastics. One group of 30 previously treated patients had a utility arch used to set up cortical anchorage in the lower arch before Class II elastic wear; the second group was treated with standard edgewise mechanics where anchorage preparation consisted of full appliances, a well-aligned mandibular arch, and a rectangular arch wire. The groups were selected according to age, sex, and the amount of Class II elastic usage. Pretreatment and posttreatment cephalometric radiographs were used to generate 32 variables. A Student's t test was used to evaluate treatment change between the groups and revealed that there were no statistically significant differences. Lower molar teeth extruded and moved mesially equally in both groups. Although cortical anchorage did not retard lower molar movement, it was no less effective in controlling molar movement with a partial appliance than the fully banded standard edgewise appliance.     

Intermaxillary forces during activator treatment

The mode of action of the activator appliance is still unclear. Apart from a possible mandibular growth enhancing effect, some investigators believe that orthopedic forces may be applied to the maxilla, contributing to Class II correction by inhibition of maxillary growth. In addition, orthodontic forces may arise that produce dentoalveolar changes. The purpose of this study was to measure the magnitude of anteroposterior intermaxillary forces during wear of the activator appliance. Ten consecutive patients with Class II dental and skeletal relationships were treated with a modified activator appliance. The appliance had maxillary and mandibular segments that could be detached from each other during the measuring session. A force transducer was placed at the anterior part of the maxillary segment, and the anteroposterior force exerted by the mandibular segment was measured. Measurements were taken in the upright and reclined position at every patient visit for a period of 6 months. Results indicated that intermaxillary forces were generally in the orthodontic range (median values of 100 gf at the upright position and 123 gf at the reclined position). A wide variation in force levels was noted, both between patients and for the same patient during the experimental period. No statistically significant change in force levels was observed during the 6 month period and no difference was noted between upright and reclined posture.     

Control of the vertical dimension in Class II correction using a cervical headgear and lower utility arch in growing patients. Part I

A retrospective cephalometric study was performed comparing three groups of 30 growing patients with Class II, Division 1 malocclusions. Group 1 was treated with a cervical headgear/lower utility arch combination (CHG/LUA), group 2 was treated with a cervical headgear alone (CHG), and the third group was untreated. The average treatment time was 1 year, 6 months. No other appliances were used during this period. Maxillary and mandibular dental and skeletal treatment responses were compared with an analysis of variance (ANOVA) and a Scheffe's test. In addition, a multiple stepwise regression was performed to determine whether pretreatment measures of facial pattern were accurate predictors of mandibular rotational response. Both treatment groups demonstrated significant reduction in maxillary protrusion. The CHG-only group showed significantly greater anterior descent of the palatal plane as compared with the untreated group. The maxillary molars showed significant distal movement in both treatment groups without any extrusion beyond that seen with normal growth. The maxillary incisor demonstrated significant retroclination in the CHG-only group. There was no statistical difference among the groups for variables commonly used for measuring mandibular rotation or protrusion. The change in vertical position of the lower molar was not significantly different among the groups. A CHG as used in this study produced maxillary orthopedic and orthodontic changes without upper molar extrusion beyond that seen with normal eruption and in the absence of an opening rotation of the mandible, even in subjects with dolicocephalic facial patterns. The LUA did not appear to influence lower molar eruption or mandibular rotational response. None of the commonly used predictors of facial pattern, such as the Y-axis, XY-axis, or MP angle, accurately predicted mandibular rotational response. Further study would be necessary to ascertain whether this was a result of their invalidation as predictors, or a result of the treatment strategy employed.     

Skeletal maturation in adolescence: a comparison between the Tanner-Whitehouse II and the Fels method

In this longitudinal study, skeletal ages assessed with the Fels method and the Tanner-Whitehouse II method (TW II) were compared for boys (n = 30) and girls (n = 30) with a mean chronological age between 12 and 16 years. The subjects, participating in the Amsterdam Growth and Health Study, were measured annually between 1977 and 1980, which resulted in four radiographs of the left hand and wrist of every individual. For boys, the mean TW II skeletal age was 0.32 years older than the mean Fels skeletal age (sd 0.50). Tested at the subsequent chronological ages, the mean TW II skeletal ages were 0.05-0.47 years older, the differences being statistically significant at the mean ages of 13, 14 and 15 years. For girls, the mean TW II skeletal age was 0.20 years younger than the mean Fels skeletal age (sd 0.69). At the subsequent chronological ages, the mean TW II skeletal ages were 0.03 to 0.35 year younger, the differences being statistically significant at the mean chronological ages of 14 and 15 years. As a consequence of the differences between the methods, application of the Fels method resulted in classifying a smaller percentage of boys (10%) as rapid maturers, and a higher percentage (6.7%) of boys as normal maturers in comparison to the TW II method. For girls, a higher percentage of female adolescents were classified as rapid (16.7%) and slow maturers (13.3%), but a smaller percentage was classified as normal mature (30%). Differences in the skeletal ages can be ascribed to differences in maturation of the reference population, but also to fundamental differences in the statistical methods of the scoring system and the scales of maturity. CONCLUSION: There is no agreement in skeletal ages assessed according to the TW II method and the Fels method in adolescence.     

Craniofacial adaptations induced by chincup therapy in Class III patients

The purpose of the present study is to examine the effects of an orthopedic force produced by chincup treatment in patients with Class III malocclusion. Anteroposterior maxillary and mandibular changes were examined as were changes in the vertical dimension. Further, the possibility of posterior displacement of temporomandibular joints in treated Class III subjects was evaluated. Serial lateral headfilms of 22 young females (average age, 9 years), who had received chincup therapy were compared with those of 20 skeletal Class III subjects of similar age who received no treatment during the interval studied. A computerized x-y coordinate program was applied to analyze the cephalometric landmarks and measurements. The treated group showed improvement of the skeletal Class III pattern associated with a slight increase (0.8 degrees per year) in SNA and a slight decrease (-0.7 degrees per year) in SNB and also a decreased gonial angle. The distance from the condyle to the chin (Co-Gn or effective mandibular length) increased significantly less in the treated group in comparison with controls. Increases in lower anterior facial height were not different between the treated and untreated groups. In addition, the cranial base angles N-S-Ba and N-S-Ar showed no statistical difference between groups, but these angles tended to increase with time in both groups. Basion and Articulare showed almost the same amount of backward and downward movement in both groups. The results of this study indicate that the primary effect of chincup therapy was in producing a reduction in mandibular growth increments during the period studied. Maxillary growth was not affected during treatment. Further, the results of this study fail to support the hypothesis that chincup appliance significantly induces the posterior displacement of the glenoid fossa.     

Usefulness of multiple burr-hole operation for child Moyamoya disease]

The purpose of this study was to examine the cephalometric changes that occur with palatal expansion/facemask therapy for Class III malocclusion. Pretreatment and posttreatment lateral cephalograms from 21 patients were traced and analyzed by traditional cephalometric measures, an x-y coordinate system, and along the functional occlusal plane. Differences between T1 and T2 values were analyzed with paired t-tests. Mean ages were 7.26 years (T1) and 8.18 years (T2). Average treatment time was 11.05 months. Statistically significant anterior movement of the maxilla occurred with increases in SNA (+2.35), maxillary depth (+2.22), and ANB (+3.66), and anterior movement of A-point (+3.34 mm) and ANS (+3.17 mm). The maxilla rotated counterclockwise, with PNS moving down more than ANS (-2.21 mm and -0.82, respectively). The mandible rotated clockwise with mild decreases in SNB (-1.32) and facial depth, (-1.2) but significant downward movement at menton (-4.34 mm). Occlusal plane analysis demonstrated that the correction was due more to the maxilla than the mandible (+2.35 and -1.88 mm, respectively). The maxillary molars moved forward (+1.70 mm) as did the incisors (+1.75 mm). Soft tissue changes included the nose and upper lip moving forward (3.43 and 3.67 mm, respectively), and menton moving downward (-3.49 mm). The results indicate that facemask/palatal expansion therapy improves Class III malocclusion by a combination of skeletal and dental changes that occur the anteroposterior dimension and in the vertical plane of space.     

Aging of the population: demographics for the Liege region

We present the case of a 26-year-old man who at the age of 9 suffered severe trauma to both maxillary central incisors. The underlying malocclusion was skeletal and classified as dental Class II/1 with severe crowding. Both the maxillary central incisors and the two lower first premolars were extracted and the patient was treated with an edgewise appliance for 2 years. Acceptable occlusal relationships were achieved following orthodontic and adjunctive treatment which consisted of reshaping the maxillary lateral incisors with composite materials and grinding the canines to resemble lateral incisors. A critical evaluation of the esthetic and functional results at the age of 26 years is presented.     

Magnetic activator device II (MAD II) for correction of Class II, division 1 malocclusions

A magnetically active, two-piece (upper and lower), functional orthopedic appliance has been developed, magnetic activator device (MAD) for the correction of Class II malocclusions. The magnetic forces are used to give freedom of mandibular movement and to allow for continuous functioning of the orofacial muscles when the appliance is worn. Samarium cobalt (Sm2Co17) magnets are incorporated on the buccal aspects of the upper and lower appliances. Magnetic forces ranging from 150 to 600 gm per side have been used on patients, and it seems that the skeletal versus dental response depends on the intensity of the magnetic force used. A force of 300 gm, when the magnets are in contact, on each side has been found to be an appropriate value in patients age 7 to 12 years. The use of this less bulky design rather than a traditional orthopedic appliance, along with the freedom of function it permits, has enabled patients to wear the appliance nearly 24 hours in most cases.     

A modified, lingually supported cantilevered Herbst appliance

This new, fixed-functional appliance/Herbst/Bioprogressive system is designed for patient comfort and mandatory compliance. It also combines the positive clinical effects of four fixed-functional systems. It allows rapid palatal expansion of the upper arch, alveolar uprighting of the lower arch, upper and lower incisor alignment, and sagittal correction of Class II malocclusions to occur simultaneously with one appliance fixed in both arches. It is indicated for use in growing patients with skeletal Class II malocclusions. The ideal timing for treatment is the late mixed dentition. Being able to remove the appliance after one year with the upper second bicuspids erupting slightly Class III so the clinician can immediately begin fixed finishing mechanics would be ideal. This new Herbst design will reduce the frequency of orthognathic surgery and upper bicuspid extraction to camouflage Class II malocclusions. At the same time, it gives total control to the clinician in treating some more difficult, non-compliant patients. Fixed-functional appliances, which improve treatment efficiency and treatment results and provide for patient comfort, while at the same time give the treating clinician almost total control of the three planes of facial growth will open new doors for orthodontic treatment and research in the next century.     

A prospective evaluation of Bass, Bionator and Twin Block appliances. Part II--The soft tissues

A prospective clinical study with a random allocation of 47 patients to three different functional appliance groups was established and compared with a slightly younger control group over a 9-month period. The cephalometric hard tissue changes were assessed in relation to the soft tissue changes produced and the patients were also assessed by three-dimensional (3D) laser scanning of the facial soft tissues. Each 'averaged' appliance group scan was compared with the 'averaged' control group face. Statistically and clinically significant changes occurred in the group treated with the Twin Block appliance, and to a lesser extent in the group treated with the Bionator appliance. No statistically significant facial soft tissue changes could be demonstrated in the Bass appliance group. Upper lip position remained stable despite the significant overjet reduction attained in the three appliance groups. Lower lip protrusion (up to 3.8 mm), lower lip length (up to 4.0 mm), and soft tissue lower and total face height increased significantly in all appliance groups by varying amounts. The long-term effect of these changes needs to be fully evaluated. The laser scanning system was found to be a sensitive and accurate method of quantitatively assessing small changes in the soft tissue facial form. Significant changes of the facial tissues in the transverse plane were highlighted by this technique.     

A case of bilateral optic neuropathy and recurrent transverse myelopathy associated with perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA)

The purpose of this study was to evaluate skeletal and dental effects of bionator headgear combination appliances on patients in development period with Class II, division 1 malocclusion. The comparison of computerized X-ray cephalometric measurements between the 26 treated children and 26 untreated children was made. The results showed that ANB angle was significantly reduced and horizontal mandibular growth development tended to be normal in the treated group. It was suggested that the bionator headgear combination appliance can restrain the maxillary growth early and promote the forward mandibular growth which contribute the functional jaws correction.     

406 femoral fractures in children

406 fractures of the femur in persons younger than 17 years of age were treated at Haukeland University Hospital, Bergen, from January 1980 to December 1993. The incidence was 35/100,000 per year; 57/100,000 for boys, and 24/100,000 for girls. No significant changes in the incidence occurred during the study period. 70% of the fractures occurred in boys. 78% had an isolated fracture, while 7% had other fractures, 7% head injuries and 8% injuries of multiple organs as well. Traffic accidents accounted for 35% of the fractures. 65% of the femur fractures were treated by skeletal traction (mean hospitalisation 30 days), 21% were operated on initially (hospitalisation 12 days), and 14% were given early spica cast (hospitalisation three days). The results of the treatment were generally satisfactory. Neither anisomelia (8.5% more than 10 mm) nor malrotation (12% more than 10 degrees) of the femur was a serious problem, but the length of time the patients were hospitalized was rather long.     

Carcinosarcoma and pseudosarcoma of the esophagus: two names, one disease--comprehensive review of the literature

The purpose of this investigation was to evaluate the treatment effects of an intraoral appliance used for rapid distal movement of the maxillary molars. The appliance studied, the Jones jig, is designed to deliver a distalizing force to the maxillary molar against an intraoral anchorage unit thereby eliminating the need for patient compliance. A retrospective study was performed comparing before and after lateral cephalometric radiographs on 13 patients who were treated for an average of 26 weeks with the Jones jig. The cephalometric radiographs were evaluated to determine if there were significant differences between pretreatment and posttreatment variables that included skeletal, dental and soft tissue relationships. Differences between the pretreatment and posttreatment means were significant for mesial angulation of the premolar anchorage unit (P <.001), distal movement of the maxillary molars (P <.01), mesial movement of the premolar anchorage unit (P <. 01), mesial movement of the maxillary incisors (P <.001), and increased lower anterior facial height (P <.01). The anchorage loss, flared maxillary incisors, and increased facial height are negative treatment effects that should be expected when using this or similar appliance design.