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.     

The effect of treatment with the Bass appliance on skeletal Class II malocclusions: a cephalometric investigation

The purpose of this investigation was to study the short-term effects of treatment with the Bass appliance by comparative evaluation of treated and untreated skeletal Class II malocclusions. The subjects consisted of forty-seven Class II, division 1 malocclusion cases. Twenty-seven (14 girls, 13 boys) were treated with the Bass appliance for an average of 6 months. The remaining 20 cases (6 girls, 14 boys) served as a control. At the end of the 6 month treatment period the statistically significant treatment changes could be summarized as follows: the sagittal skeletal relationship was improved as a result of favourable growth responses in both the maxilla and the mandible. The overjet was reduced and the molar relationship was corrected as a result of the extended skeletal changes. Distal movement of the upper dentition was evident, with unchanged inclination of the maxillary incisors. Both anterior and posterior facial heights were increased without changes in the inclinations of the palatal and mandibular planes. No significant dental movement was observed in the mandible.     

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 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.     

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.     

The arc index in evaluation of Class III malocclusion

Lateral cephalometric radiographs were obtained for 46 individuals (18 men and 28 women) aged 20 to 30 years. The sample consisted of Taiwanese with Class III malocclusions and prognathic facial profiles. A modification of the Sassouni arch analysis was used to evaluate this group. All parameters were compared with the norms for adult Taiwanese. The facial pattern of the Class III group was similar to that reported in other studies. The maxilla was in a retrusive position; the lengths of the maxilla and the mandible were significantly different from those in the normal group; the mandibular central incisor was retroinclined; and the total gonial angle, upper gonial angle, and lower gonial angle in the Class III group were significantly different from those angles in the normal group in both sexes. The arc index represented the maxillomandibular positional relationship. There was a statistically significant difference between the mean arc indexes of the Class III and the normal groups. The results indicated that the more negative the arc index, the greater the Class III tendency.     

Thin-plate spline analysis of the cranial base in subjects with Class III malocclusion

The role of the cranial base in the emergence of Class III malocclusion is not fully understood. This study determines deformations that contribute to a Class III cranial base morphology, employing thin-plate spline analysis on lateral cephalographs. A total of 73 children of European-American descent aged between 5 and 11 years of age with Class III malocclusion were compared with an equivalent group of subjects with a normal, untreated, Class I molar occlusion. The cephalographs were traced, checked and subdivided into seven age- and sex-matched groups. Thirteen points on the cranial base were identified and digitized. The datasets were scaled to an equivalent size, and statistical analysis indicated significant differences between average Class I and Class III cranial base morphologies for each group. Thin-plate spline analysis indicated that both affine (uniform) and non-affine transformations contribute toward the total spline for each average cranial base morphology at each age group analysed. For non-affine transformations, Partial warps 10, 8 and 7 had high magnitudes, indicating large-scale deformations affecting Bolton point, basion, pterygo-maxillare, Ricketts' point and articulare. In contrast, high eigenvalues associated with Partial warps 1-3, indicating localized shape changes, were found at tuberculum sellae, sella, and the frontonasomaxillary suture. It is concluded that large spatial-scale deformations affect the occipital complex of the cranial base and sphenoidal region, in combination with localized distortions at the frontonasal suture. These deformations may contribute to reduced orthocephalization or deficient flattening of the cranial base antero-posteriorly that, in turn, leads to the formation of a Class III malocclusion.     

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.     

Variation in maxillary and mandibular molar and incisor vertical dimension in 12-year-old subjects with excess, normal, and short lower anterior face height

Maxillary and mandibular molar and incisor vertical dimensions were evaluated in subjects who had excessive, normal, and short lower anterior face height in relation to upper face height. Sexual dimorphism was also investigated. The dentoalveolar heights were compared between Class I and Class II, dental and skeletal malocclusions. The sample was drawn from the Burlington Growth Centre sample and consisted of 188 male and 156 female subjects at age 12 years, for whom lateral head films were available. This sample was classified into excessive, normal, and short lower anterior face height, using the ratio upper anterior face height/lower anterior face height (UAFH/LAFH). The results showed that the dentoalveolar heights are significantly different between faces with excessive, normal, and short lower anterior face heights, except for the lower posterior dental height, which showed no difference between short and normal lower anterior face height subjects. All dentoalveolar heights are larger for male subjects except for the upper posterior dental height. Dentoalveolar heights are similar between Class I and Class II dental and skeletal malocclusions. The upper teeth present a higher correlation to the UAFH/LAFH ratio than the lower teeth. Stepwise regression analysis shows that 22% of the variation in the ratio is explained by the maxillary and mandibular molars and 41% is explained by the maxillary and mandibular incisors.     

Shape-coordinate analysis of skeletal changes induced by rapid maxillary expansion and facial mask therapy

The aim of this study was to evaluate maxillary and mandibular shape/size changes by means of Bookstein's shape-coordinate and tensor analysis in children with Class III malocclusions treated with rapid maxillary expansion and a facial mask in order to define optimum timing of intervention for this type of therapy. The treated group (46 subjects, 26 females and 20 males) was divided into two subgroups according to the stage of dentitional development. The early-treated group consisted of 23 subjects treated in the early mixed dentition (mean age at Time 1, 6 years 9 months +/- 7 months); the late-treated group included 23 subjects treated in the late mixed dentition (mean age at Time 1, 10 years 3 months +/- 1 year). The mean treatment period was about 11 months. The control group (32 subjects with untreated Class III malocclusion, 18 females and 14 males) also was divided into two subgroups (an early control group, 17 subjects in the early mixed dentition, and a late control group, 15 subjects in the late mixed dentition). Maxillary triangles (point T, the most superior point of the anterior wall of sella turcica, point FMN, the fronto-maxillary-nasal suture, and point A) and mandibular triangles (point Condylion, point Gonion, and point Pogonion) were digitized on cephalograms in both groups at Time 1 and Time 2. Combined facial mask and rapid maxillary expansion therapy produced a significant enhancement of the forward growth of the maxilla and significantly more upward and forward direction of growth of the mandibular condyle (leading to smaller increments in mandibular total length, Co-Pg) in the early-treated group when compared with controls and to the late-treated group. Both maxillary size and mandibular size were significantly affected by treatment in the early mixed dentition. The results of this study indicate that orthopedic treatment of Class III malocclusion induces favorable size and shape changes both in the maxilla and mandible, and that this combined treatment approach is more effective in the early mixed dentition than in the late mixed dentition.     

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.     

Skeletal effects of early treatment of Class III malocclusion with maxillary expansion and face-mask therapy

The effectiveness of maxillary expansion and face-mask therapy in children with Class III malocclusion was studied in a sample of 46 subjects in mixed dentition and compared with a control sample of 32 subjects with untreated Class III malocclusion. Treated and untreated samples were divided into early and late mixed-dentition groups to aid identification of the optimum timing of the orthopedic treatment of the underlying skeletal disharmony. Cephalometric analysis was based on a stable basicranial reference system, appropriate for longitudinal studies started in the early developmental ages. The level of significance for intergroup comparisons was set at a p value of 0.01. Significant forward displacement of the maxillary complex was found in the early-treatment group. The region of the pterygomaxillary suture, in particular, showed significant changes in the subjects treated during early mixed dentition. No significant maxillary modifications were recorded in the late-treatment group. Both early and late groups exhibited smaller increments in mandibular protrusion and larger increments in the intermaxillary vertical relationship compared with their respective Class III control groups. Only children treated at an early age, however, showed a significant upward and forward direction of condylar growth, leading to smaller increments in total mandibular length. These results indicate that the combination of a bonded maxillary expander and face-mask therapy is more effective in early mixed dentition than in late mixed dentition, especially with regard to the magnitude of the protraction effects on maxillary structures.     

Diagnosis and treatment planning of hypodivergent skeletal pattern with clockwise occlusal plane rotation

Diagnostic treatment planning of Class III malocclusion is complicated due to the interaction of development, timing, dental pattern, and skeletal relationships. Historically, the treatment of adult Class III malocclusions has tended to be seen primarily as cases of mandibular prognathism. As diagnostic acumen and surgical skills improve and merge, orthodontic and surgical treatment plans for Class III malocclusions have become more common. Class III malocclusions now tend to be described in terms of mandibular prognathism, horizontal maxillary hypoplasia, maxillary vertical hypoplasia, and mandibular dentoalveolar retrusion. The purpose of this paper is to present a combined surgical-orthodontic treatment approach involving clockwise rotation of the occlusal plane for treatment of hypodivergent Class III skeletal pattern and dental malocclusion.     

Genetic profile of pNOB8 from Sulfolobus: the first conjugative plasmid from an archaeon

Recently, children born small for gestational age (SGA) with a catch-up growth failure, have been selected for high dose growth hormone (GH) treatment. In order to gain greater insight concerning dentofacial growth and maturation of these patients, and to evaluate the possible effects of high does GH administration on facial structures, craniofacial growth and dental maturation were evaluated in short SGA persons. Seventy-seven cephalograms and orthopantomograms were available from 48 subjects, aged between 2 and 32 years. Craniofacial growth was assessed by calculating age- and gender-specific standard deviation scores (SDS) for eight linear and five angular measurements. Tooth formation was evaluated by means of a dental delay score (i.e. dental age minus chronological age). The SDS for craniofacial growth measurements for the lateral aspect showed a short anterior cranial base (-1.8 SDS), a small retropositioned mandible (< or = -1.7 SDS) and a small maxilla (-1.5 SDS); a high mandibular plane angle (+1.9 SDS) and a wide cranial base angle (+1 SDS). These findings result in a small retrognathic face with a relatively increased lower anterior face height (+1.7 SDS). In contrast to skeletal maturation, dental age was not delayed. The general growth retardation is, apparently, reflected to a differential extent within the craniofacial complex, while dental maturation appears to be a distinct process tightly linked to chronological age, and independent of general growth and bone age.     

A cephalometric comparative study of the soft tissue airway dimensions in persons with hyperdivergent and normodivergent facial patterns

PURPOSE: This study was performed to compare the dimensions of the nasopharynx, oropharnynx, and hypopharynx of persons with hyperdivergent and normodivergent facial types, and to determine whether any variations exist. PATIENTS AND METHODS: Lateral cephalometric records of a population with a normodivergent facial pattern (n = 23) and a group with a hyperdivergent facial pattern (n = 27) as evidenced by increased mandibular plane angle were used to compare the soft tissue airway dimensions. Statistical analysis consisted of Student's t-tests, Wilcoxon rank sums, and chi2. Statistical significance was set .05. RESULTS: Overall the hyperdivergent group had a narrower anteroposterior pharyngeal dimension than the normodivergent control group. This narrowing was specifically noted in the nasopharynx at the level of the hard palate and in the oropharynx at the level of the tip of the soft palate and the mandible. In addition, the posterior pharyngeal wall had a thinning at the level of the inferior border of the third cervical vertebrae, and there was a more obtuse palatal angle. The tongue was also positioned more inferiorly and posteriorly in the hyperdivergent group, as evidenced by the increased distance between the hyoid bone and the mandibular plane and the increased distance between the soft palate tip and the epiglottis. The hyperdivergent group had more retruded maxillary and mandibular apical bases and a higher Class II skeletal discrepancy. CONCLUSIONS: The narrower anteroposterior dimension of the airway in hyperdivergent patients may be attributable to skeletal features common to such patients, that is, retrusion of the maxilla and the mandible and vertical maxillary excess. Other features, such as an obtuse soft palate and low-set hyoid, also may be contributory factors. The relatively thin posterior pharyngeal wall observed in hyperdivergent patients might be a compensatory mechanism.     

Assessment of symphysis morphology as a predictor of the direction of mandibular growth

The purpose of this study was to determine whether symphysis morphology could be used as a predictor of the direction of mandibular growth and to assess growth changes of the symphysis. Cross-sectional data included lateral cephalometric radiographs of 115 adults (58 women, 57 men) with the longitudinal sample a subset of 62 subjects (30 females, 32 males) at four age groups. The direction of mandibular growth was evaluated with seven cephalometric measurements that included Y-axis, SN to mandibular plane, palatal plane to mandibular plane, gonial angle, sum of saddle, articulare and gonial angles, percentage lower facial height, and posterior/anterior face height. The mandibular symphyseal dimensions studied were height, depth, ratio (height/depth), and angle. Symphysis morphology was found to be associated with the direction of mandibular growth, especially in male subjects with symphysis ratio having the strongest relationship. A mandible with an anterior growth direction was associated with a small height, large depth, small ratio, and large angle of the symphysis. Conversely, a posterior growth direction was associated with a large height, small depth, large ratio, and small angle of the symphysis. Symphysis dimensions continued to change until adulthood with male subjects having a greater and later occurring change compared with female subjects.     

Skeletal stability after mandibular advancement: a comparison of two rigid internal fixation techniques

OBJECTIVE: To compare two different methods of rigid fixation for any difference in postoperative stability after mandibular advancement. MATERIAL AND METHODS: Thirty-eight patients with Class II malocclusion treated by bilateral sagittal split osteotomy (BSSO) and mandibular advancement were selected for this retrospective study. Group A (n = 16) had noncompressive bicortical screws inserted in the gonial area through a transcutaneous approach and Group B (n = 22) had the bone segments fixed with unicortical screws and miniplates on the lateral surface of the mandibular body. Cephalograms were taken preoperatively, 2 days postoperatively, and 6 months after the operation, and a computer program was used to superimpose the three cephalograms and register the advancement and postoperative instability. RESULTS: There was a minimal difference in advancement of the mandible in the two groups. Statistical analysis showed no significant difference in postsurgical stability. However, positive correlation between the amount of advancement and the amount of postsurgical instability was demonstrated using a linear multiple regression test (P = .0002). CONCLUSION: This study indicates that the two different methods of internal rigid fixation of the segments after surgical advancement of the mandible give equal stability postoperatively and their use is a matter of surgical choice.     

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.     

Occlusal stability in Class II, Division 1, deep bite cases followed up for many years after orthodontic treatment

This case report analyzes long-term occlusal stability that can be achieved in Class II, Division 1, deep bite cases with active treatment finished during the period of maxillomandibular growth. The analysis was designed to identify occlusal features common to two cases at the end of active treatment and to study how the occlusion changed with growth and jaw movement to achieve stability. The following occlusal features were shared by the two cases at the end of active treatment: (1) AB plane and axes of the maxillary and mandibular posterior teeth were perpendicular to functional occlusal plane; (2) the axis of the lower incisor was almost perpendicular to DC-L1i line; (3) the anterior occlusion was overcorrected to or near an edge-to-edge relationship. Items 1 and 2 remained unchanged throughout the follow-up periods, regardless of growth status, and the overjet and overbite increased during maxillomandibular growth after treatment. During the period of mandibular growth alone, after the end of retention, the axes of maxillary incisors tipped labially; as a result, F line became parallel to CDM line by the end of growth. The labial tipping of maxillary incisors brought the lower incisal edge into contact with or extremely near the inflection point (Bp).1 By the end of growth, the tangent of Bp became parallel to or coincident with DC-L1i line and perpendicular to the axis of the lower incisor, and the DC-L1i lines at various times posttreatment were almost parallel to each other in the two cases. Overjet increased as the maxillary incisors tipped labially, providing proper protrusive and retrusive paths for mandibular guidance. The angle between the functional occlusal plane and CDM line stayed almost the same as at the end of active treatment in the two cases, suggesting a possible change in the angle of eminence in harmony with the functional occlusal plane. These factors apparently contributed to the long-term occlusal stability in the two cases.     

Evoked potentials as predictors of outcome in neonatal intensive care unit survivors: review of the literature

The twin blocks technique was developed by Dr. William Clark of Scotland during the early 1980s. Twin Blocks are an uncomplicated system that incorporates the use of upper and lower bite blocks. These bite blocks reposition the mandible and redirect occlusal forces to achieve rapid correction of malocclusions. They are also comfortable and the patients wear them full-time--including eating time. Occlusal forces transmitted through the dentition provide a constant proprioceptive stimulus to influence the rate of growth and the trabecular structure of the supporting bone. This feature of Twin Blocks means easier and quicker treatment. The occlusal inclined plane is the fundamental functional mechanism of the natural dentition. Twin Blocks are bite blocks that effectively modify the occlusal inclined plane to induce favorably directed occlusal forces by causing a functional mandibular displacement. Upper and lower bite blocks interlock at a 45 degree angle and are designed for full-time wear to take advantage of all functional forces applied to the dentition including the forces of mastication. The patients who were treated with Modified Twin Blocks received the following benefits: 1) large overjets and deep overbites were corrected. 2) Class II molar relationships were changed into Class I, and 3) the profiles of the patients were improved by anterior displacement of mandible.