Vertical Skeletal Changes Research Articles

Treatment effects of bonded RME and vertical-pull chincup followed by fixed appliance in patients with increased vertical dimension

The aim of this study was to investigate the effectiveness of vertical-pull chincup (VPCC) therapy during an initial rapid maxillary expansion (RME) phase, followed by a second phase of comprehensive orthodontic therapy in growing subjects with mild-to-severe hyperdivergent facial patterns. The records of 29 subjects treated with bonded RME combined with VPCC followed by a fixed-appliance phase with continued use of VPCC were compared with a group of 29 well-matched patients treated with bonded RME only. Lateral cephalograms were analyzed before the start of treatment (T1), before the second phase of treatment (T2), and after the second phase of treatment (T3). Mean age at T1 was approximately 9 years for both groups. Total treatment period (phase 1, interim phase, and phase 2) was 5.7 years for the VPCC group and 6.2 years for the bonded RME-only group. Statistical comparison between the 2 groups was performed by means of independent sample t tests on the T2-T1, T3-T2, and T3-T1 changes. Cervical vertebral maturation stages were assessed at T1, T2, and T3. The VPCC induced significantly smaller increases in mandibular plane angle of about 2 degrees , lower anterior facial height of about 2.5 mm, and total anterior facial height of about 3.5 mm, compared with the RME-only subjects. These outcomes reflect the therapeutic changes that occurred during phase 1 treatment; phase 2 treatment was not associated with any significant difference in treatment response. No statistically significant differences in vertical dentoalveolar changes were concurrent with the vertical skeletal changes in the subjects treated with the VPCC compared with the RME-only group. The clinical significance of VPCC wear over 2 phases of treatment (5.7 years) appears to be limited. The VPCC was most effective during the initial (RME) phase of treatment and of little benefit during the fixed appliance phase.

Intraosseous screw-supported upper molar distalization.

The aims of the present study were to investigate (1) the efficiency of intraosseous screws for anchorage in maxillary molar distalization and (2) the sagittal and vertical skeletal, dental, and soft tissue changes after maxillary molar distalization using intraosseous screw-supported anchorage. Twenty-five subjects (18 girls and seven boys; 11.3 to 16.5 years of age) with skeletal Class I, dental Class II malocclusion participated in the study. An anchorage unit was prepared for molar distalization by placing an intraosseous screw behind the incisive canal at a safe distance from the midpalatal suture following the palatal anatomy. The screws were placed and immediately loaded to distalize upper first molars or the second molars when they were present. The average distalization time to achieve an overcorrected Class I molar relationship was 4.6 months. The skeletal and dental changes were measured on cephalograms and dental casts obtained before and after the distalization. In the cephalograms, the upper first molars were tipped 8.8 degrees and moved 3.9 mm distally on average. On the dental casts, the mean distalization was five mm. The upper molars were rotated distopalatally. Mild protrusion (mean 0.5 mm) of the upper central incisors was also recorded. However, there was no change in overjet, overbite, or mandibular plane angle measurements. In conclusion, immediately loaded intraosseous screw-supported anchorage unit was successful in achieving sufficient molar distalization without major anchorage loss.

The accuracy of preoperative orthognathic predictions

We assessed the accuracy of preoperative OPAL™ orthognathic predictions by retrospective analysis of 25 Class II patients who had had orthodontic treatment combined with mandibular advancement osteotomy. Preoperative and postoperative lateral cephalographs were digitised and surgical predictions generated using OPAL software. Each prediction was compared with the corresponding clinical changes. We also made a method error study by doing a random retracing of 25 cephalographs.Predictions of some of the principal OPAL values (SNA, ANB, LAFH%, OJ, OB) were reasonably accurate in terms of mean values. However, there were large individual variations for most variables and predictions of the vertical skeletal, incisor, and Wits measurements were imprecise. In particular, there was a bias towards under-prediction of the vertical skeletal changes when there was more backward mandibular rotation than anticipated. Immediate postoperative cephalographs were also affected by a 2.1mm mean downward displacement of the mandible as a result of the surgical wafer.

Natural craniofacial changes in the third decade of life: A longitudinal study

The aim of this study was to evaluate longitudinally the natural craniofacial and dentoalveolar changes that occur in the third decade of life. Natural head position lateral cephalometric films and dental casts of 30 people (14 women and 16 men) were evaluated. The mean age at the beginning of the observation period was 22.35 years for the women and 22.19 years for the men, and the observation period was approximately 10 years. Cephalometric films were superimposed by the structural method, and the measurements of the dental casts were made with a digital caliper. All tracings were digitized, and changes in the 65 cephalometric and 10 dental cast measurements were evaluated statistically. In this early adult period, small changes were found in the craniofacial and craniocervical parameters; the changes were more significant in the women. The most significant changes were found in the vertical dimension. The total anterior face height increased in both genders, while the lower anterior face height increased significantly in the female group. Soft tissue measurements reflected the vertical skeletal changes. The retrusion of the upper lip was significant in the women, and the upper lip thickness decreased in both genders. In the dentoalveolar region, the main movement was eruption of the teeth. The overbite amount increased significantly only in the female group. All dental arch measurements decreased in both sexes. The decrease in the mandibular arch length discrepancy was significant in the men. These findings have important clinical implications regarding the long-term stability and retention of orthodontic and orthognathic surgery treatment results. (Am J Orthod Dentofacial Orthop 2002;122:512-22)

Vertical skeletal and dental changes in earlytreatment of class II malocclusion

Increases in the vertical dimension can be detrimental in certain facial types or unstable in others. By using cephalograms, this study examined the skeletal and dental changes as well as their permanence in a group of children participating in a randomized clinical trial on the timing of Class II orthodontic treatment. Children (mean age, 9.6 years) were assigned to either a headgear/biteplane (n = 94), bionator (n = 86), or observation (n = 82) group. Cephalometric data were obtained from tracings at baseline, after Class I molar was obtained or 2 years after treatment had elapsed, and after 1 year of retention or observation. In general, the skeletal changes, such as total anterior and posterior face height and mandibular plane angle, observed during the active phase of early treatment persisted until the end of phase I. Phase I treatment also produced dental changes, such as molar eruption and tip. With the exception of the eruption of the mandibular molars in the bionator group, these changes could not be maintained until the end of phase I. Whether the subjects were in retention or not had little impact on any of the studied parameters. Mandibular plane angle, pretreatment, and retention had an affect on the mandibular molar tip over the course of the study.

Evidence of correction of open bitemalocclusion using active vertical corrector treatment

This study used a cephalometric analysis that isolated tipping and bodily tooth movements of the upper and the lower incisors and measured vertical skeletal changes in the anterior region of the maxilla and mandible to evaluate the outcome of two-phase nonextraction treatment for open bite malocclusion. Twenty-nine subjects treated with an active vertical corrector (AVC) followed by fixed 022 orthodontic appliances were selected by one orthodontist from his private practice. All subjects lacked vertical incisor contact at the start of treatment and had adequate initial, end of phase 1, and deband lateral cephalograms. Each subject in the treated group was matched by age and sex with an untreated subject from the Broadbent Bolton Collection, Cleveland, OH. Data were collected for three time intervals; phase 1 treatment with the AVC (T1 to T2), phase 2 fixed-appliance treatment (T2 to T3), and over the total treatment period (T1 to T3). Analysis of the data showed no statistically significant ( P ≤ .002) changes between treated subjects and controls for any variables during the phase 1(T1 to T2) or phase 2 (T2 to T3) treatment intervals. However, overbite was significantly improved compared with controls ( P ≤5 .002) during the T1 to T3 time interval. It was concluded that two-phase treatment with the AVC followed by fixed orthodontic appliance treatment results in a statistically significant increase in incisor overbite. The observed increase in overbite was the result of small but clinically significant changes in relative mandibular vertical growth, bodily incisor movement toward the occlusal plane, and lingual tipping of the lower incisors.

A longitudinal study of skeletal side effects induced by rapid maxillary expansion

Orthopedic expansion of the maxillary arch—rapid maxillary expansion (RME)—is a commonly used treatment technique that has become increasingly popular during the last 25 years. During this time, however, clinicians routinely have imputed a variety of undesirable side effects to RME, particularly bite opening. Whereas there have been many explanations as to the mechanisms underlying such RME-related effects as bite opening, few studies have considered the long-term effects of RME in the vertical and sagittal dimensions of the face. The purpose of this investigation was to examine cephalometrically the long-term effect that the Haas-type rapid maxillary expansion may have on bite opening and on the anteroposterior position of the maxilla. The sample consisted of 25 patients who had undergone RME with the Haas-type expander, followed by standard edgewise therapy. This RME sample was compared with a group of 25 patients who had standard edgewise treatment (SET) only and with a control (CTRL) group of 23 subjects. Mean initial form and mean age at start of treatment for the RME, SET, and CTRL groups were similar. Statistically significant among-group differences were documented for only 2 of 10 cephalometric variables sensitive to anteroposterior and vertical skeletal changes. These differences, however, were not clinically significant. The current investigation implies therefore that RME therapy with the Haas-type expander has little long-term (more than 6 years after treatment) effect on either the vertical dimensions or the anteroposterior dimensions of the face. (Am J Orthod Dentofac Orthop 1997;112:330-7.)

Vertical skeletal change associated with Andresen, Harvold, and Begg treatment

A retrospective cephalometric study was carried out to compare the vertical skeletal changes between patients treated with an Andresen (30), Harvold (19), or Begg (30) appliance, and an untreated control group (24). It was found that angular changes between the anterior cranial base, the maxillary and mandibular planes, and the y axis of growth showed a transient increase during treatment with the exception of SN-MxP in the Harvold group which decreased. Long-term these tended to relapse and the changes were not significant. Lower anterior face height was increased by 0.4 mm/annum long-term (P less than 0.01) in the Andresen group and upper anterior face height was restrained by 0.5 mm/annum (P less than 0.01) with the Harvold appliance. No significant changes were found in posterior face heights.