Valmy Pangrazio-Kulbersh

Stability of orthopedic and surgically assisted rapid palatal expansion over time

At the present time no reports are available on the stability between orthopedic and surgically assisted rapid palatal expansion. This study was designed to examine and compare the dental and skeletal changes over time for both orthopedic maxillary expansion and surgically assisted palatal expansion. The study was divided into two groups. Group one was orthopedically expanded and consisted of 14 males and 10 females. The ages ranged from 6 years to 12 years with a mean of 8.5 years. Group two received surgically assisted rapid palatal expansion and consisted of 12 males and 16 females with ages ranging from 13 years to 35 years and a mean age of 19.25 years. All 52 subjects were white, from the same geographic area, and were treated by the same two operators. Dental models and posterior anterior cephalograms were obtained immediately before and after expansion, at removal of the expansion device, and 1 year after removal of the appliance. A repeated measures analysis of variance test was applied to assess changes over time between groups. The surgical and nonsurgical techniques displayed similar trends over time although the surgical group contained a greater quantity of expansion. Both the orthopedic and the surgical groups showed stable results.

Treatment effects of the mandibular anterior repositioning appliance in patients with Class II skeletal malocclusions.

OBJECTIVE To examine the changes produced by the mandibular anterior repositioning appliance (MARA) appliance and compare the treatment effects to an untreated Class II control group. MATERIALS AND METHODS Thirty consecutively treated patients were matched with an untreated control group. Lateral cephalograms were taken at T1, 5 months pre-MARA (CVMS 2.7); T2, immediately after MARA removal and prior to placement of full fixed edgewise appliances (CVMS 4.2); and T3, at least 2 years after MARA removal and completion of edgewise treatment (CVMS 5.4). The mean age of the MARA patients was 11.9 years for boys and 10.8 years for girls. Repeated-measures analysis of variance (ANOVA) was used to assess if the samples were morphologically comparable at the outset and to test if there were significant differences between the groups for the various increments of change. Given a significant ANOVA, the source of the difference was explored via Tukey-Kramer tests. RESULTS Restriction of maxillary growth and no significant mandibular growth were observed with the MARA appliance. The Class II correction was obtained mainly by slight maxillary molar distalization and intrusion, in addition to mesial migration of the lower molars and flaring of the lower incisors. No vertical effect was observed with this appliance. CONCLUSION The MARA appliance was effective in the treatment of Class II malocclusions. Restriction of maxillary growth and dentoalveolar changes in the maxillary and mandibular arches were responsible for the correction of the Class II malocclusion. Significant mandibular growth did not contribute to this correction.

Effects of protraction mechanics on the midface

Forty patients with Class III maxillary deficiencies were each treated with a bonded maxillary palatal expansion appliance followed by protraction. Nineteen of the 40 patients were retained with a Frankel III appliance. This group was compared with 24 Class I patients treated solely with bonded expansion appliance mechanotherapy. To determine at which level protraction mechanics affects the maxilla, the Walkers analysis and other cephalometric measurements were used. The protraction group showed significant increases (p <.05) in the following measurements: ANB angle, Wits, A perpendicular to nasion and in sella to A point. Anterior molar movement, without changes in posterior nasal spine or upper incisor to SN, was evident (p <.05). Favorable change in the facial profile was noted. There were no changes in the angles between sella-nasion and its relationship with the Frankfurt, occlusal, palatal, and mandibular planes. Walkers analysis showed no change in the position of orbitale. The control group did not demonstrate any significant changes in the position of the maxillary complex as a result of expansion mechanics. The retention group maintained the position of the maxilla postprotraction. Facial contour was maintained and other profile related variables improved.

Photographic analysis of facial changes associated with maxillary expansion.

Previous studies on the effects of surgical and rapid palatal expansion have been largely based on general skeletal and dental findings ascertained from radiographs and casts. The aim of this study was to measure and compare the soft tissue changes of the face during the expansion process and to determine the stability of any changes 1 year later. The sample consisted of 44 patients with unilateral or bilateral posterior crossbites. Twenty-four of the patients required a surgically assisted expansion procedure, and a second group of 20 patients were treated with orthopedic expansion. Ten measurements were made from standardized frontal facial photographic slides at 5 intervals of treatment: initial, bond appliance, stop expansion, debond appliance, and 1 year retention. Differences over time between the surgical and nonsurgical groups were analyzed by a 2 way multivariate analysis of variance (MANOVA) and post hoc t tests. Differences between initial and 1 year retention were found in the nasal widths (P <.001) of both surgical and nonsurgical groups. Other significant changes and trends were discussed.

Long-Term Dentoskeletal Changes with the Bionator, Herbst, Twin Block, and MARA Functional Appliances

OBJECTIVE To determine if the long-term dentoskeletal changes in patients treated with tooth-borne functional appliances were comparable to each other and to matched controls. MATERIALS AND METHODS The experimental sample consisted of 80 consecutively treated patients who were equally divided into Bionator, Herbst, Twin Block, and mandibular anterior repositioning appliance (MARA) groups. The control group comprised 21 children with untreated skeletal Class II malocclusions. Lateral cephalograms were taken for the treated group at T1 (initial records), T2 (completion of functional therapy), and T3 (completion of fixed appliance therapy). A repeated measure analysis of variance (ANOVA) was used to assess the differences between and within groups. If ANOVA results were significant, Tukey-Kramer tests were used to determine where the significant differences occurred. RESULTS (1) Temporary restriction of maxillary growth was found in the MARA group (T2-T1). (2) SNB increased more with the Twin Block and Herbst groups when compared with the Bionator and MARA groups. (3) The occlusal plane significantly changed in the Herbst and Twin Block groups. (4) The Twin Block group expressed better control of the vertical dimension. (5) The overbite, overjet, and Wits appraisal decreased significantly with all of the appliances. (6) The Twin Block group had significant flaring of the lower incisors at the end of treatment. (7) Over the long-term, there were no significant soft tissue changes among treated and untreated subjects. CONCLUSIONS No significant dentoskeletal differences were observed long-term, among the various treatment groups and matched controls.

Cone beam computed tomography evaluation of changes in the naso-maxillary complex associated with two types of maxillary expanders.

OBJECTIVE To test the hypothesis that there were no differences in the skeletal and dental effects of banded vs bonded expanders when evaluated using cone beam computed tomography (CBCT). MATERIALS AND METHODS The experimental sample consisted of 23 patients: 13 (seven male, six female; mean age  =  12.6 ±1.8 years) and 10 (five male, five female; mean age  =  13.5 ± 2.1 years) treated with banded and bonded maxillary expanders, respectively. CBCT images were taken at T1 (pretreatment) and T2 (immediately after expansion) to evaluate the changes in the naso-maxillary complex. Relationships between and within groups were assessed using analysis of variance. If the results were significant, post hoc t-tests were used to determine where the significant differences occurred. RESULTS Regardless of the appliance, the maxilla was expanded equally at the level of the canines and first and second premolars. At the level of the first molars, more dental tipping and alveolar bending were evident in the banded expander group. Both appliances equally increased the skeletal and soft tissue dimensions of the nasal cavity and maxillary sinus volume. The posterior airway volume did not significantly change with either method of expansion. CONCLUSIONS The hypothesis was rejected. Both appliances expanded the maxilla similarly. However, in the banded group, more dental tipping and alveolar bending occurred at the level of the first molars. Maxillary expansion affected the palatal suture and demonstrated anterior and posterior skeletal widening of the nasal cavity, with corresponding soft tissue changes and increased airway volume.

Early treatment outcome assessed by the Peer Assessment Rating index

In this study, the Peer Assessment Rating (PAR) index was used to objectively evaluate early treatment outcomes. Pretreatment and posttreatment casts of 103 consecutively treated patients were analyzed. The mean chronological, skeletal, and dental ages were 9. 82, 9.76, and 9.32 years, respectively. Calibrated examiners scored all models using the PAR ruler. PAR scores were weighed by means of a validation exercise. Cronbach alpha reliability analysis was used to establish the consistency of the subjective rating among 10 orthodontists of the severity of malocclusion. Pearsons correlation coefficient was used to assess the association among the orthodontists and the total PAR scores. Multiple regression analysis was used to determined the optimum weight of the PAR scores. Pretreatment and posttreatment differences were evaluated with t tests. The association between PAR scores and classification of malocclusions and treatment categories was assessed by means of multivariate analysis of variance (MANOVA). A reduction in the PAR index was observed for the mean raw and weighted scores, from 15.82 to 8.82 and from 5.28 to 3.73, respectively (P <.001). Twenty percent of the sample greatly improved the PAR index, by a 70% reduction.3 Forty-eight percent improved scores by at least a 30% reduction.4 The remaining 32% did not reduce scores by at least 30%. Subjects with both Class I and Class II malocclusions reduced their scores similarly. There was no statistically significant association between reduction of PAR scores and treatment modalities.

A comparative and correlational study of the cranial base in North American blacks.

The purpose of this investigation was to compare the cranial bases of blacks and whites in regard to length, angulation, and flexure, and to determine what proportion of the differences in facial measurements can be explained by the variability seen in the cranial base. Standardized cephalograms of 100 native-born North American black adults were traced, analyzed, and compared with white values. The measurements selected depicted dependency and independency from the cranial base. Mean differences between the races and the sexes were assessed with the Students t test. Models of linear regression between the cranial base measurements and all other parameters were computed for both sexes and correlation coefficient values calculated. This study established that the length of the cranial base in North American blacks is significantly shorter from that of whites. A strong biologic relationship was demonstrated between the length of the cranial base of blacks and their denture bases, the palatal, and occlusal planes. The data suggest that most of the cephalometric differences between blacks and whites are not simply anatomic for measurements using sella nasion as their reference plane.

Dentoskeletal effects of functional appliances vs bimaxillary surgery in hyperdivergent Class II patients

OBJECTIVE To compare treatment outcomes of growing and nongrowing Class II patients characterized by mandibular retrusion and increased vertical dimension. MATERIALS AND METHODS Seventeen patients (mean age 9 years 5 months) were treated with a Bionator fabricated with posterior bite block and high-pull headgear, while 15 patients (mean age 23 years 6 months) received Le Fort I osteotomy for maxillary impaction and mandibular advancement. These groups were compared with 17 nontreated control subjects from the Bolton and Michigan growth studies. Lateral cephalograms taken for the functional group at T1 (initial records), T2 (completion of functional appliance treatment), and T3 (completion of comprehensive treatment) were compared with radiographs taken at T1 (initial records), T2 (immediate post surgery), and T3 (1 year post surgery) for the surgical patients. A null hypothesis of no difference in treatment outcomes between the functional and surgical groups was proposed. A mixed-design analysis of variance was used to compare changes within and between groups. Significance was set at P ≤ .002. RESULTS In the functional appliance group, the mandible showed a more favorable growth direction and rotation. Both groups had stable results over time and finished treatment with similar cephalometric measurements. CONCLUSION Both the functional appliances and orthognathic surgery resulted in similar dentoskeletal treatment changes. The control groups did not self correct either in the anteroposterior or vertical dimensions.

CBCT assessment of alveolar buccal bone level after RME.

OBJECTIVE To evaluate the maxillary alveolar buccal bone levels after expansion with banded and bonded expanders, using cone-beam computed tomography (CBCT). MATERIALS AND METHODS The population sample consisted of 22 patients who required expansion during their comprehensive treatment; 10 patients (five males and five females) with a mean age of 13.5 years (CVMS 3) had bonded hygienic expanders, and 12 (six males and six females) with a mean age of 12.6 years (CVMS 3) had banded hyrax expanders. CBCT was taken both before (T1) and 6 months after last activation (T2). Measurements were made for buccal bone thickness (BT), buccal marginal bone level (MBL), and bone thickness level (BTL) at the right first molar (M(Rt)), left first molar (M(Lft)), right first premolar (PM(Rt)), and left first premolar (PM(Lft)). A mixed-design analysis of variance assessed differences between and within the groups. Post hoc t-tests were completed on significant analysis of variance results to determine where differences occurred. RESULTS Analysis of variance revealed no significant differences between or within the two groups. BT significantly decreased horizontally following rapid maxillary expansion. The amount of bone lost was -0.59 mm M(Rt), -0.72 mm PM(Rt), -0.50 mm M(Lft), and -0.57 mm PM(Lft) (P < .003). CONCLUSIONS There was no significant difference between or within the two groups. Buccal bone loss in the vertical dimension (MBL) only showed significance in the banded group for M(Rt) (0.63 mm) and PM(LFt) (0.37 mm) as evidenced by the paired t-test (P < .05).