Palatal growth studied on human autopsy material. A histologic microradiographic study

Skeletal and dentoalveolar changes after miniscrew-assisted rapid palatal expansion in young adults: A cone-beam computed tomography study

Objective

The aim of this study was to evaluate the skeletal and dentoalveolar changes after miniscrew-assisted rapid palatal expansion (MARPE) in young adults by cone-beam computed tomography (CBCT).

Methods

This retrospective study included 14 patients (mean age, 20.1 years; range, 16–26 years) with maxillary transverse deficiency treated with MARPE. Skeletal and dentoalveolar changes were evaluated using CBCT images acquired before and after expansion. Statistical analyses were performed using paired t-test or Wilcoxon signed-rank test according to normality of the data.

Results

The midpalatal suture was separated, and the maxilla exhibited statistically significant lateral movement (p < 0.05) after MARPE. Some of the landmarks had shifted forwards or upwards by a clinically irrelevant distance of less than 1 mm. The amount of expansion decreased in the superior direction, with values of 5.5, 3.2, 2.0, and 0.8 mm at the crown, cementoenamel junction, maxillary basal bone, and zygomatic arch levels, respectively (p < 0.05). The buccal bone thickness and height of the alveolar crest had decreased by 0.6–1.1 mm and 1.7–2.2 mm, respectively, with the premolars and molars exhibiting buccal tipping of 1.1°–2.9°.

Conclusions

Our results indicate that MARPE is an effective method for the correction of maxillary transverse deficiency without surgery in young adults.

Assessment of the efficiency of Erbium-YAG laser as an assistant method to rapid maxillary expansion: An in vivo study

INTRODUCTION

Maxillary transverse deficiency (MTD) is one of the most pervasive and common skeletal problems in the craniofacial complex. This study aimed to evaluate the effect of associating the application of Erbium-YAG laser with rapid maxillary expansion (RME) for treating MTD in young adult patients with permanent dentition in regard to skeletal and dental effects.

METHODS

Twenty-four subjects, aged from 15.5 to 19 years and needing RME as a therapeutic procedure, were randomly assigned to either the laser group (n=12) or the control group (n=12). The RME was realized by a two bands hyrax expander cemented on upper first molars. Patients in the laser group were undergone mucosal-bony perforations along the midpalatal suture every month, for three consecutive months, using Erbium-YAG laser. Postero-anterior cephalograms were taken for all patients. Skeletal and dental changes before and after RPE as well as at the end of the retention phase were collected and compared for both groups. Total time needed for expansion and retention were recorded and compared.

RESULTS

The findings showed more significant changes in most maxillofacial components in the laser group after the expansion phase. However, there was no significant differences with respect to retention or total treatment duration.

CONCLUSIONS

Laser assisted rapid maxillary expansion (LARME) can be a good approach to use for improving skeletal effects in young adult patients suffering from MTD.

Relationship between maturation indices and morphology of the midpalatal suture obtained using cone-beam computed tomography images

Objective

The purpose of this study was to determine whether predicting maturation of the midpalatal suture is possible by classifying its morphology on cone-beam computed tomography (CBCT) images and to investigate relationships with other developmental age indices.

Methods

The morphology of the midpalatal suture was assessed by using CBCT images of 99 patients. Axial plane images of the midpalatal suture were classified into five stages according to the classification scheme. To make the assessment more accurate, the morphology and fusion of the midpalatal suture were additionally investigated on coronal cross-sectional planar images and volume-rendered images. Bone age was evaluated using the hand and wrist method (HWM) and cervical vertebrae method (CVM); dental age (Hellman's index), sex, and chronological age were also assessed. To evaluate relationships among variables, Spearman's rho rank test was performed along with crosstabs using contingency coefficients.

Results

The HWM and CVM showed strong correlations with the maturation stage of the midpalatal suture, while other indices showed relatively weak correlations (p < 0.01). Through crosstabs, the HWM and CVM showed high association values with CBCT stage; the HWM demonstrated slightly higher values (p < 0.0001). Based on the HWM, the midpalatal suture was not fused until stage 6 in both sexes.

Conclusions

Among developmental age indices, the HWM and CVM showed strong correlations and high associations, suggesting that they can be useful in assessing maturation of the midpalatal suture.

Prediction of rapid maxillary expansion by assessing the maturation of the midpalatal suture on cone beam CT

Rapid maxillary expansion (RME) primarily involves the mechanical opening of the midpalatal suture of the maxillary and palatine bones. The fusion of the midpalatal suture determines the failure of RME, a common event in late adolescents and young adults. Recently, the assessment of the maturation of midpalatal suture as viewed using cone beam computed tomography (CBCT) has been introduced. Five maturational stages of the midpalatal suture have been presented: Stage A = straight high-density sutural line, with no or little interdigitation; Stage B = scalloped appearance of the high-density sutural line; Stage C = two parallel, scalloped, high-density lines that lie close to each other, separated in some areas by small low-density spaces; Stage D = fusion of the palatine bone where no evidence of a suture is present; and Stage E = complete fusion that extends also anteriorly in the maxilla. At Stage C, less skeletal response would be expected than at Stages A and B, as there are many bony bridges along the suture. For patients at Stages D and E, surgically assisted RME would be necessary, as the fusion of the midpalatal suture already has occurred either partially or totally. This diagnostic method can be used to estimate the prognosis of the RME, mainly for late adolescents and young adults for whom this procedure is unpredictable clinically.

Rapid maxillary expansion in adults: Can multislice computed tomography help choose between orthopedic or surgical treatment?

INTRODUCTION

The aim of this study was to evaluate the accuracy of Multislice Computed Tomography (MSCT) in the detection resistance areas on the midpalatal suture (MPS) and thus to evaluate if MSCT could be a help in the kind of maxillary expansion to be used (pure orthodontic or surgically-aided) for the correction of transverse maxillary deficiencies in adults.

METHODS

Ten MSCT were obtained from 10 MPS removed from fresh corpses (mean age: 79.4; extreme: 70-86). Three standardized radiological regions of interest (ROI) were identified on each MPS and were classified into "open" (group 1) or "closed" (group 2) by 3 independent radiologists. The 30 ROI were then histologically analyzed according to 3 criteria: mean suture width (MSW), obliteration index (OI) and interdigitation index (Ii).

RESULTS

Nine ROI were classified in group 1 (closed) and 21 in group 2 (open). On the histological examination, the mean MSW was 396.9μm in group 1 and 227.1μm in group 2. OI was 3.098% and 9.309% and Ii was 1.25 and 1.34 respectively. Statistically significant difference between the 2 groups was only found for the MSW. We conclude that MSCT allows for the evaluation of the width of the MPS, but not for the evaluation of the other possible parameters of resistance we used. Therefore, it cannot predict precisely the amount of résistance in the MPS and is not suited for the choice between pure orthodontic or surgically-aided expansion.

Evaluation of the stiffness characteristics of rapid palatal expander screws

Background

The aim of this study is to evaluate the mechanical properties of the screws used for rapid expansion of the upper jaw.

Methods

Ten types of expansion screw were assessed, seven with four arms: Lancer Philosophy 1, Dentaurum Hyrax Click Medium, Forestadent Anatomic Expander type “S”, Forestadent Anatomic Expander type “S” for narrow palates, Forestadent Memory, Leone A 2620-10 with telescopic guide, and Leone A 0630-10 with orthogonal arms; and three with two arms: Dentaurum Variety S.P., Target Baby REP Veltri, and Leone A 362113. A test expander with the mean dimensions taken from measurements on a sample of 100 expanders was constructed for each screw. The test expanders were connected to the supports of an Instron 4467 (Instron Corp., USA) mechanical testing machine equipped with a 500 N load cell, and the compression force exerted after each activation was measured. The mean forces expressed by the two- and four-arm expanders were then compared.

Results

After five activations, the forces expressed by the two-arm devices were double than those expressed by the four-arm devices on average (224 ± 59.9 N vs. 103 ± 32.9 N), and such values remained high after subsequent activations.

Conclusions

The expanders tested demonstrated stiffness characteristics compatible with opening of the palatine sutures in pre-adolescent patients. The stiffness of such devices can be further increased during the construction phase.

Quantitative evaluation of midpalatal suture maturation via fractal analysis

Objective

The purpose of this study was to determine whether the results of fractal analysis can be used as criteria for midpalatal suture maturation evaluation.

Methods

The study included 131 subjects aged over 18 years of age (range 18.1–53.4 years) who underwent cone-beam computed tomography. Skeletonized images of the midpalatal suture were obtained via image processing software and used to calculate fractal dimensions. Correlations between maturation stage and fractal dimensions were calculated using Spearman's correlation coefficient. Optimal fractal dimension cut-off values were determined using a receiver operating characteristic curve.

Results

The distribution of maturation stages of the midpalatal suture according to the cervical vertebrae maturation index was highly variable, and there was a strong negative correlation between maturation stage and fractal dimension (−0.623, p < 0.001). Fractal dimension was a statistically significant indicator of dichotomous results with regard to maturation stage (area under curve = 0.794, p < 0.001). A test in which fractal dimension was used to predict the resulting variable that splits maturation stages into ABC and D or E yielded an optimal fractal dimension cut-off value of 1.0235.

Conclusions

There was a strong negative correlation between fractal dimension and midpalatal suture maturation. Fractal analysis is an objective quantitative method, and therefore we suggest that it may be useful for the evaluation of midpalatal suture maturation.

A 22-year follow-up of the nonsurgical expansion of maxillary and mandibular arches in a young adult: Are the outcomes stable, relapsed, or unstable with aging?

Adult maxillary and mandible arch expansion without a surgical approach can be uncertain when long-term stability is considered. This case report describes the treatment of a 19-year-old woman with an Angle Class I malocclusion with constricted maxillary and mandibular arches. The patient's main complaint was mandibular anterior crowding. The treatment plan included expansion of the mandibular arch concurrent with semirapid maxillary expansion. An edgewise appliance was used to adjust the final occlusion. Smile esthetics and dental alignment were improved without straightening the profile. This outcome was followed up with serial dental casts for 22 years after treatment. At the end of that period, the occlusion and tooth alignment were clinically satisfactory, further supported by mandibular fixed retention. However, the transverse widths were continuously and gradually reduced over time, superposing orthodontic transverse relapse and natural arch constriction caused by aging.

How effective is the Invisalign® system in expansion movement with Ex30' aligners?

OBJECTIVES

The aims of this study are to validate a new method for quantifying the predictability of expansion movement with the Invisalign® system and to determine whether there are statistically significant differences between planned expansion with ClinCheck® and actual clinical quantification using upper post-treatment model comparisons.

MATERIALS AND METHODS

A sample of 116 patients subjected to expansion with Invisalign® was studied. The following variables were measured at T1 and T2 on 3D models and ClinCheck®: canine gingival width, first premolar gingival width, second premolar gingival width, first molar gingival width, canine cuspid width, first premolar cuspid width, second premolar cuspid width, first molar cuspid width, canine depth, arch depth, first molar rotation, first right and left molar rotation, and first molar inclination.

RESULTS

Measurement error was tested, showing good precision for all variables. The paired test showed non-significant differences between the 3D model and ClinCheck® at T1 for all variables except first molar cuspid width and arch depth. Statistically significant differences were found for canine gingival width, first premolar gingival width, second premolar gingival width, first molar gingival width, canine cuspid width, first premolar cuspid width, second premolar cuspid width, first molar cuspid width, and canine depth when the 3D model and ClinCheck® were compared at T2.

CONCLUSIONS

Differences between the 3D model and ClinCheck® at T2 showed that planned expansion at the end of treatment is not predictable.

CLINICAL RELEVANCE

This is the first in vivo human study to quantify the predictability of expansion in patients with Invisalign® Ex30 material.

Correction of transverse maxillary deficiency and anterior open bite in an adult Class III skeletal patient

Transverse maxillary deficiency may be associated with sagittal or vertical problems of the maxilla or mandible. It may contribute to unilateral or bilateral posterior crossbite, anterior dental crowding, and unesthetic black buccal corridors on smiling. An adequate transverse dimension is important for stable and proper functional occlusion. Surgically, assisted rapid palatal expansion has been the treatment of choice to resolve posterior crossbite in skeletally mature patients. The following case report presents an adult Class III skeletal patient with an anterior open bite and bilateral posterior crossbite which was treated by surgically assisted rapid maxillary expansion with satisfactory outcomes.

Bone-borne distractor versus tooth-borne distractor for orthodontic distraction after surgical maxillary expansion: The patient's point of view

INTRODUCTION

Orthodontic distraction after surgical maxillary expansion is a mode of treatment regularly used in the context of transverse maxillary constriction. There is, however, no consensus in the literature as to the type of distractor (bone-borne or tooth-borne) that should be used.

PATIENTS AND METHOD

This retrospective study compared orthodontic distraction using a bone-borne or a tooth-borne distractor from the point of view of tolerance, ease of use and overall patient satisfaction, by means of a questionnaire completed by patients undergoing maxillary expansion surgery in the Stomatology and Maxillofacial Surgery Department of Lille University Hospital between January 2013 and March 2015. The efficacy of the two distractors was also assessed.

RESULTS

Thirty-two patients were included: 10 in the bone-borne distractor group and 22 in the tooth-borne group. Sixty percent of patients questioned found the bone-borne distractor easy to use compared with 32% for the tooth-borne distractor (P=0.167). Tolerance was noted to be comparable and acceptable by the two groups. The overall satisfaction rate was high for both groups at over 90%, and was correlated with ease of use and clear information. The average space gain between the first molars was 11.1mm with the bone-borne device and 10.7mm for the tooth-borne appliance.

CONCLUSION

The use of a bone-borne distractor for orthodontic distraction after maxillary expansion surgery appears to be an effective, simple and well-tolerated alternative to the use of a tooth-borne distractor. According to patients, this distractor also appears easier to use than the traditional Hyrax-type distractor. This ease of use is correlated with overall satisfaction.

A unique functional craniofacial suture that may normally never ossify: A cone-beam computed tomography-based report of two cases

The premise of complete ossification of midpalatal suture in early adulthood still has its popularity, though conflicting data are emerging in the literature. A 49-year-old male and a 54-year-old female Iranian patient, both dentulous, were referred to a Maxillofacial Radiology Center to be evaluated for implant insertion. In cone-beam computed tomography (CBCT) evaluation, an in-ossified suture was found in anterior two-third of midpalatal region of both individuals. The application of clinical vignettes from CBCT findings for maxillofacial orthodontic and orthopedic purposes is of value. Existing cases of successful nonsurgical rapid palatal expansion of maxilla in adults could surrogate this dogma about timing for ossification of midpalatal suture which is considered as a purely chronologic-related phenomenon and transmitted masticatory forces may be one possible cause (functional hypothesis).

Bone thickness of the anterior palate for orthodontic miniscrews

OBJECTIVE

To determine the bone thickness in the anterior palate and to test whether there is any dependency between bone thickness and patient's age or gender and whether there is any difference between left and right sides.

MATERIALS AND METHODS

Cone beam computed tomographic (CBCT) evaluations (n  =  431; 229 females, 202 males) of healthy orthodontic patients aged 9-30 years were selected from the database of the imaging center network Mesantis. In each CBCT image, palatal bone thickness was determined as the median and 2, 4, 6, and 8 mm paramedian bilaterally. Bone height was measured perpendicularly to the bony surface at 10, 12, 14, 16, 18, and 20 mm from the cementoenamel junction of the maxillary central incisor in the sagittal plane.

RESULTS

The greatest bone thickness was found in the lateral anterior palate. Palatal bone thickness of male patients was on average 1.2 mm greater than that of females. Bone height of 9-13-year-olds was less than that of older patients. No difference could be determined between the left and right side.

CONCLUSIONS

The lateral anterior palate offers the greatest bone thickness. Because there is considerable variation of bone thickness between individuals, a CBCT evaluation is recommended if maximum screw length is to be used.

Stresses in the midpalatal suture in the maxillary protraction therapy: a 3D finite element analysis

Background

The aim of the present work was to evaluate the stress magnitudes and directions along the midpalatal suture in the maxillary protraction therapy.

Methods

The geometry of the maxilla and teeth were digitally reconstructed based on computer tomography images obtained from the skull of a girl in a mixed dentition stage with skeletal and dental class III malocclusion. An appliance commonly used for rapid palatal expansion (RPE) was also digitally modeled for anchorage of the protraction force and meshed for finite element analysis. The maxillary protraction was simulated applying 600 cN (300 cN for each side) directed 30° forward and downward to the maxillary occlusal plane.

Results

The principal stresses, through the force application, exhibited similar distribution patterns. A higher stress area was observed in the region of the midpalatal suture located in front of the incisive canal. All the sections showed vectors of compressive nature.

Conclusions

Because of the compressive nature of the stresses distributed along the midpalatal suture in the maxillary protraction therapy simulation, which is opposite to the natural growth transversal tendency, maxillary expansion is advisable in clinical cases.

Effect of Surgically Assisted Rapid Maxillary Expansion on Upper Airway Volume: A Systematic Review

PURPOSE

Surgically assisted rapid maxillary expansion (SARME) is required in non-growing patients when maturity or resistance precludes desired sutural separation by noninvasive techniques. The aim of this review was to determine what volumetric changes occur in the upper airway spaces after SARME in adults.

MATERIALS AND METHODS

A systematic review was performed with data assessed for suitability of meta-analysis. The primary outcome measurement of volumetric changes in an upper airway space was sought in non-growing patients undergoing SARME. Electronic database searches were performed for published literature in Medline (by Ovid), Pre-Medline, Old Medline, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) spanning all available years to August 1, 2015. Unpublished literature was searched electronically through ClinicalTrials.gov and the National Research Register. Additional hand searching of reference lists of relevant articles, grey searching, and expert correspondence was conducted for any additional studies. Two authors independently screened search results, extracted data, and assessed the risk of bias of included studies.

RESULTS

Twenty-one studies were located by initial screening; 10 were excluded after full-text review, leaving 11 studies eligible that met all inclusion criteria for this systematic review. In total, 204 treated patients (mean age, 18 to 31 yr) were included in the qualitative synthesis. Ten studies evaluated nasal cavity volume, 2 evaluated palatal volume, and 1 evaluated oropharyngeal volume. Appliances used included tooth-borne hyrax and transpalatal distractor devices.

CONCLUSIONS

SARME was found to produce substantial short-term volume increases in the nasal cavity in non-growing patients that were maintained for at least 63 months. Evidence weakly suggested no effect on oropharyngeal volume. However, most studies were evaluated as having a high risk of bias. The effect of such volume changes on respiratory function still needs to be determined; thus, SARME cannot be recommended for respiratory purposes.

Periodontal, dentoalveolar, and skeletal effects of tooth-borne and tooth-bone-borne expansion appliances

INTRODUCTION

The purposes of this study were to evaluate and compare the periodontal, dentoalveolar, and skeletal effects of tooth-borne and tooth-bone-borne expansion devices using cone-beam computed tomography.

METHODS

Twenty-five patients requiring maxillary expansion were randomly allocated into 2 groups. A tooth-borne hyrax appliance was used in the first group, consisting of 13 patients (8 girls, 5 boys; mean age, 14.3 ± 2.3 years), and a tooth-bone-borne hybrid hyrax appliance was used in the second group of 12 patients (6 girls, 6 boys; mean age, 13.8 ± 2.2 years). Cone-beam computed tomography records were taken before and 3 months after expansion, and periodontal, dentoalveolar, and skeletal measurements were made on the cone-beam computed tomography images with a software program. The 2 independent-samples t test and the Mann-Whitney U test were used to evaluate treatment changes for both groups. Paired-samples t test and Wilcoxon test were used to compare the measurements at 2 time points for variables.

RESULTS

Significant skeletal changes and increases in interdental distances were observed in both groups. However, the distances between the first and second premolars increased more with the hyrax appliance (7.5 ± 4.2 and 7.9 ± 3.3 mm, respectively) than with the hybrid hyrax (3.2 ± 2.6 and 4.5 ± 3.8 mm, respectively) (P <0.05). Similar reductions in buccal bone plate thickness and increases in palatal bone plate thickness of the anchored teeth occurred in both groups, whereas changes in buccal and palatal bone thicknesses of the left first premolars significantly differed between groups (P <0.001). No significant intergroup difference was found in terms of absolute dental tipping.

CONCLUSIONS

Both tooth-borne and tooth-bone-borne rapid expansion are effective methods for treating a narrow maxilla. However, the hyrax appliance resulted in greater expansion in the premolar region. On the other hand, the hybrid hyrax appliance did not cause changes in the bony support of the first premolars.

Displacements prediction from 3D finite element model of maxillary protraction with and without rapid maxillary expansion in a patient with unilateral cleft palate and alveolus

Background

Both maxillary protraction and rapid expansion are recommended for patients with cleft palate and alveolus. The aim of the study is to establish a three-dimensional finite element model of the craniomaxillary complex with unilateral cleft palate and alveolus to simulate maxillary protraction with and without rapid maxillary expansion. The study also investigates the deformation of the craniomaxillary complex after applied orthopaedic forces in different directions.

Methods

A three dimensional finite element model of 1,277,568 hexahedral elements (C3D8) and 1,801,945 nodes was established based upon CT scan of a patient with unilateral cleft palate and alveolus on the right side in this study. A force of 4.9 N per side was directed on the anatomic height of contour on the buccal side of the first molar. The angles between the force vector and occlusal plane were −30°, −20°, −10°, 0°, 10°, 20°, and 30°. A force of 2.45 N on each loading point was directed on the anatomic height of contour on the lingual side of the first premolar and the first molar to simulate the expansion of the palate.

Results

The craniomaxillary complex displaced forward under any of the loading conditions. The sagittal and vertical displacement of the craniomaxillary complex reached their peak at the protraction degree of −10° forward and downward to the occlusal plane. There were larger sagittal displacements when the maxilla was protracted forward with maxillary expansion. The palatal plane rotated counterclockwise under any of the loading conditions. Being protracted without expansion, the dental arch was constricted. When supplemented with maxillary expansion, the width of the dental arch increased. Transverse deformation of the dental arch on affected side was different from that on unaffected side.

Conclusions

Protraction force alone led the craniomaxillary complex moved forward and counterclockwise, accompanied with lateral constrain on the dental arch. Additional rapid maxillary expansion resulted in a more positive reaction including both larger sagittal displacement and the width of the dental arch increase.

Relationship Between the Thickness of Cortical Bone at Maxillary Mid-palatal Area and Facial Height Using CBCT

INTRODUCTION

Orthodontic mini-implants have been incorporated into orthodontic treatment modalities. Adequate bone at mini-implant placement site can influence the success or failure of anchorage. The present study was to determine the thickness of cortical bone in the maxillary mid-palatal area at predetermined points for the placement of orthodontic mini-implants using Cone Beam CT technique in order to evaluate the relationship of these values with the facial height. Materials and Methods : A total of 161 patients, consisting of 63 males (39.13%) and 98 females (60.87%), were evaluated in the present study; 38% of the subjects had normal facial height, 29% had short face and 33% had long face. In order to determine which patient belongs to which facial height category, i.e. normal, long or short, two angular and linear evaluations were used: the angle between S-N and Go-Me lines and the S-Go/N-Me ratio. Twenty points were evaluated in all the samples. First the incisive foramen was located. The paracoronal cross-sections were prepared at distances of 4, 8, 16 and 24 mm from the distal wall of the incisive foramen and on each cross-section the mid-sagittal and para-sagittal areas were determined bilaterally at 3- and 6-mm distances (a total of 5 points). The thicknesses of the cortical plate of bone were determined at the predetermined points. Results : There was a significant relationship between the mean cortical bone thickness and facial height (p<0.01), with significantly less thickness in long faces compared to short faces. However, the thickness of cortical bone in normal faces was similar to that in long and short faces. Separate evaluation of the points showed that at point a16 subjects with short faces had thicker cortical bone compared to subjects with long and normal faces. At point b8 in long faces, the thickness of the cortical bone was significantly less than that in short and normal faces. At point d8, the thickness of the cortical bone in subjects with short faces was significantly higher than that in subjects with long faces. Conclusion : At the point a16 the cortical bone thickness in short faces was significantly higher than normal and long faces. The lower thickness of the cortical bone in the palatal area at points b8 and d8 in subjects with long faces might indicate a lower anchorage value of these points in these subjects.

Anchorage onto deciduous teeth: effectiveness of early rapid maxillary expansion in increasing dental arch dimension and improving anterior crowding

Background

Anchorage onto permanent dentition is a common procedure in rapid maxillary expansion. However, replacing first permanent molars with the second deciduous molars seems to be an option to reduce some negative side effects during orthodontic treatment. The purpose of this study was to evaluate the dental effect of rapid maxillary expansion with anchorage exclusively onto deciduous teeth performed in the first period of transition.

Methods

Twenty patients with a lateral cross-bite treated exclusively by a Haas expander in early mixed dentition were retrospectively analyzed before treatment, at appliance removal, and at 21 months out of retention. The sagittal and transverse dimensions, together with the inter-canine arch and irregularity index, were digitally measured on scanned images of dental casts. The patients were compared with three balanced control groups (in total, 60 individuals) matched for gender. Two control groups had the same canine dental class as the treated group at T1, were in the inter-transitional period, and either had or lacked a lateral cross-bite. The last control group was comprised of adolescents in permanent dentition with a dental class I. The statistical analysis was performed by means of repeated-measures ANOVA for paired data and one-way ANOVA, the Kruskal-Wallis test, and the Mann-Whitney test for independent measures (α-level p < 0.05).

Results

At the end of follow-up (inter-transitional period of dentition), the dental arch dimensions of treated patients were similar to those of adolescents with a dental class I and significantly wider than those of patients with a lateral cross-bite. Also, the anterior irregularity index was lower among patients who had undergone expansion treatments than in all untreated study participants.

Conclusions

The Haas expander anchored to the deciduous teeth is effective in increasing the dental arch width in patients with a lateral cross-bite. The dimensions of the dental arch were modified earlier toward the values of the permanent dentition.

Surgically assisted rapid palatal expansion with tent screws and a custom-made palatal expander: a case report

Rapid palatal expansion(RPE) with the tooth-born appliance is not sufficient to apply to the patients with periodontal problem or insufficient tooth anchorage, and it leads to tipping of the anchorage teeth and increasing teeth mobility and root resorption. To avoid these disadvantages, we present the case using palatal screws and custommade palatal expander. A 23-year-old patient underwent surgically assisted rapid maxillary expansion with the Hyrax expansion using 4 tent screws. The study models were used to measure the pre−/−post surgical width of the anterior and posterior dental arches with a digital sliding caliper. In the result, the custom-made palatal expander with 4 tent screws is suitable for delivering a force to the mid-palatal suture expansion. And it is low cost, small sized and simply applied. The results indicated that maxillary expansion with the custom-made palatal anchorage device is predictable and stable technique without significant complications in patients.

Evaluation of 3-dimensional superimposition techniques on various skeletal structures of the head using surface models

Objectives

To test the applicability, accuracy, precision, and reproducibility of various 3D superimposition techniques for radiographic data, transformed to triangulated surface data.

Methods

Five superimposition techniques (3P: three-point registration; AC: anterior cranial base; AC + F: anterior cranial base + foramen magnum; BZ: both zygomatic arches; 1Z: one zygomatic arch) were tested using eight pairs of pre-existing CT data (pre- and post-treatment). These were obtained from non-growing orthodontic patients treated with rapid maxillary expansion. All datasets were superimposed by three operators independently, who repeated the whole procedure one month later. Accuracy was assessed by the distance (D) between superimposed datasets on three form-stable anatomical areas, located on the anterior cranial base and the foramen magnum. Precision and reproducibility were assessed using the distances between models at four specific landmarks. Non parametric multivariate models and Bland-Altman difference plots were used for analyses.

Results

There was no difference among operators or between time points on the accuracy of each superimposition technique (p>0.05). The AC + F technique was the most accurate (D<0.17 mm), as expected, followed by AC and BZ superimpositions that presented similar level of accuracy (D<0.5 mm). 3P and 1Z were the least accurate superimpositions (0.79<D<1.76 mm, p<0.005). Although there was no difference among operators or between time points on the precision of each superimposition technique (p>0.05), the detected structural changes differed significantly between different techniques (p<0.05). Bland-Altman difference plots showed that BZ superimposition was comparable to AC, though it presented slightly higher random error.

Conclusions

Superimposition of 3D datasets using surface models created from voxel data can provide accurate, precise, and reproducible results, offering also high efficiency and increased post-processing capabilities. In the present study population, the BZ superimposition was comparable to AC, with the added advantage of being applicable to scans with a smaller field of view.

Early Treatment of Class III Malocclusion: A Boon or a Burden?

This article presents a case of class III malocclusion, a female patient aged 8 years treated in early stage of its recognition, i.e. treated in early mixed dentition stage, utilizing orthopedic appliance for its correction, utilizing both rapid maxillary expansion and face mask approach. After the skeletal base correction as part of phase of phase I therapy, a retentive plate was given and patient was asked to report every 6 months for review and monitoring of her growth pattern and phase II treatment planning after the eruption of all permanent teeth.

How to cite this article: Khan MB, Karra A. Early Treatment of Class III Malocclusion: A Boon or a Burden? Int J Clin Pediatr Dent 2014;7(2):130-136.

Comparison of maxillary molar distalization with an implant-supported distal jet and a traditional tooth-supported distal jet appliance

Aim. To investigate and compare the efficiency of two appliances for molar distalization: the bone-anchored distal screw (DS) and the traditional tooth-supported distal jet (DJ) for molar distalization and anchorage loss. Methods. Tests (18 subjects) were treated with a DS and controls (18 subjects) were treated with a DJ. Lateral cephalograms were obtained before and at the end of molar distalization and were analysed. Shapiro Wilk test, unpaired t-test, and Wilcoxon rank-sum test were applied according to values distribution. The α level was fixed at 0.05. Results. Maxillary first molars were successfully distalized into a Class I relationship in all patients. The mean molar distalization and treatment time were similar in both groups. The DS group exhibited a spontaneous distalization (2.1 ± 0.9 mm) of the first premolar with control of anchorage loss, distal tipping, extrusion, and skeletal changes. Conclusions. The DS is an adequate compliance-free distalizing appliance that can be used safely for the correction of Class II malocclusions. In comparison to the traditional DJ, the DS enables not only a good rate of molar distalization, but also a spontaneous distalization of the first premolars.

Midpalatal suture maturation: classification method for individual assessment before rapid maxillary expansion

INTRODUCTION

In this study, we present a novel classification method for individual assessment of midpalatal suture morphology.

METHODS

Cone-beam computed tomography images from 140 subjects (ages, 5.6-58.4 years) were examined to define the radiographic stages of midpalatal suture maturation. Five stages of maturation of the midpalatal suture were identified and defined: stage A, straight high-density sutural line, with no or little interdigitation; stage B, scalloped appearance of the high-density sutural line; stage C, 2 parallel, scalloped, high-density lines that were close to each other, separated in some areas by small low-density spaces; stage D, fusion completed in the palatine bone, with no evidence of a suture; and stage E, fusion anteriorly in the maxilla. Intraexaminer and interexaminer agreements were evaluated by weighted kappa tests.

RESULTS

Stages A and B typically were observed up to 13 years of age, whereas stage C was noted primarily from 11 to 17 years but occasionally in younger and older age groups. Fusion of the palatine (stage D) and maxillary (stage E) regions of the midpalatal suture was completed after 11 years only in girls. From 14 to 17 years, 3 of 13 (23%) boys showed fusion only in the palatine bone (stage D).

CONCLUSIONS

This new classification method has the potential to avoid the side effects of rapid maxillary expansion failure or unnecessary surgically assisted rapid maxillary expansion for late adolescents and young adults.

[Not Available]

Dr Birte Melsen est née à Aabenraa, au Danemark, le 9 Juin 1939.

Elle fait ses études dentaires au Royal Dental College à Aarhus, Danemark (1964).

Elle est professeur et chef du Département d’Orthodontie à l’Université dentaire, à Aarhus, depuis 1975 et traite exclusivement des adultes en pratique privée à Lübeck, en Allemagne (temps partiel depuis 1986).

Birte Melsen est l’auteur de plus de 350 articles et publications, dans des domaines aussi variés que la croissance et le développement cranio-facial (recherches sur cadavres humains), la biologie osseuse et les réactions tissulaires, la distraction osseuse, les implants dentaires, les traitements adultes, les asymétries, la stabilité à long terme, sans oublier les mini-vis orthodontiques d’ancrage temporaire, les attaches auto-ligaturantes et l’imagerie.

Bidimensional dentoalveolar distraction osteogenesis for treatment efficiency

This case report describes the treatment of a 16-year-old girl with a unilateral posterior buccal crossbite, a unilateral Class II molar relationship, and a maxillary right canine high in the labial sulcus. The treatment plan included surgically assisted unilateral maxillary expansion for the correction of the buccal crossbite, with simultaneous dentoalveolar distraction of the maxillary right canine into the extraction space of the first premolar aided by skeletal anchorage. Reduced orthodontic treatment time was facilitated by these 2 surgical procedures. A pleasing esthetic result and a good functional occlusion were achieved in 13 months.

Effects of rapid palatal expansion on the sagittal and vertical dimensions of the maxilla: a study on cephalograms derived from cone-beam computed tomography

INTRODUCTION

The purpose of this study was to use cone-beam computed tomography imaging to examine the skeletal and dental changes in the sagittal and vertical dimensions after rapid palatal expansion.

METHODS

Twenty-eight healthy children (mean age, 9.9 years; range, 7.8-12.8 years; 17 boys, 11 girls) who required rapid palatal expansion treatment were included. For each patient, a bonded Haas-type expander with full occlusal and palatal acrylic coverage was cemented in place. Cone-beam computed tomography images were obtained as part of the pretreatment orthodontic records and at the completion of rapid palatal expansion for all patients. The mean interval between pretreatment and completion of rapid palatal expansion was 52 days (range, 19-96 days). The average skeletal age of the patients, determined from hand-wrist films also obtained before treatment, was 10.1 years. The mean expansion of the expander was 8.0 mm (range, 5.9-9.6 mm). Each cone-beam computed tomography image was compressed from the outer portion of the right side of the patient's head to the center of the left central incisor into a 2-dimensional synthesized cephalogram, which was then traced and measured.

RESULTS

The results showed that from pretreatment to completion of rapid palatal expansion, SNA, FH-NA, and A-Nperp increased by means of 1.04°, 0.92°, and 0.87 mm, respectively (P <0.05). In addition, 1/-NA, 1/-SN, 1/-NA, 1/-Nperp, and 1/-PP showed mean decreases of 3.74°, 2.53°, 1.17 mm, 0.49 mm, and 2.69°, respectively (P <0.05). Both ANS and PNS moved significantly downward (ANS, 2.05 mm; PNS, 1.16 mm).

CONCLUSIONS

There was forward movement of the maxilla as a result of rapid palatal expansion treatment. Bonded rapid palatal expansion treatment resulted in downward displacement of the maxilla with a greater displacement of ANS than PNS and posterior movement of the maxillary central incisors.

Magical NiTi expander

A 24-year-old male patient was referred to our department for expansion of the constricted maxillary arch as a presurgical procedure for the correction of congenital facial disfigurement. On examination, the patient had a convex profile, increased interlabial gap, tongue thrust, limited mouth opening, posterior crossbite, asymmetric 'V'-shaped maxillary arch with severe constriction, crowding of anterior teeth in the maxillary arch and a massive open bite. Radiographic investigations included orthopantomograph and occlusal radiographs. The patient photographs and models were analysed. On careful evaluation, the treatment for maxillary arch expansion was planned with a nickel titanium (NiTi) slow maxillary expander along with fixed mechanotherapy for alignment of teeth. An unexpectedly successful outcome was appreciated from the treatment. An emphasis should be laid on selecting and treating the case of constricted arches with a surgical or non-surgical approach, as expansion can be achieved orthodontically by using NiTi expanders.

The diagnostic performance of dental maturity for identification of the circumpubertal growth phases: a meta-analysis

The present meta-analysis initially evaluates the reliability of dental maturation in the identification of the circumpubertal growth phases, essentially for determining treatment timing in orthodontics. A literature survey was performed using the Medline, LILACS and SciELO databases, and the Cochrane Library (2000 to 2011). Studies of the correlation between dental and cervical vertebral maturation methods were considered. The mandibular canine, the first and second premolars, and the second molar were investigated. After the selection, six articles qualified for the final analysis. The overall correlation coefficients were all significant, ranging from 0.57 to 0.73. Five of these studies suggested the use of dental maturation as an indicator of the growth phase. However, the diagnostic performance analysis uncovered limited reliability only for the identification of the pre-pubertal growth phase. The determination of dental maturity for the assessment of treatment timing in orthodontics is not recommended.

Paramedian vertical palatal bone height for mini-implant insertion: a systematic review

Paramedian insertion of orthodontic mini-implants is increasingly used to anchor molar distalizers. The aim of this review was to systematically examine the available measurements of vertical palatal bone height (VBH). PUBMED, MEDLINE and the Cochrane Controlled Trials Register were searched using specific search terms. Hand searches of bibliographies of articles were also performed to identify studies measuring VBH or bone thickness in the human palate. Sixteen studies were included, arising from 19 published articles. Repeat presentations were excluded. Ten of the 11 computed tomogram (CT)-based studies presented data from 956 orthodontic patients on average VBH and its variation at a range of palatal sites. Individual data were not available, and pooling of data was not feasible because of heterogeneity of subjects, different measurement sites, different CT methods and their associated software. The compilation of data did indicate that the region 3-4mm behind the incisive foramen and 3-9mm lateral to the midpalatal suture should normally provide sufficient VBH to anchor molar distalizers. The risks of unwanted effects during distalization should be small, but the limitations listed above and the small numbers of studies available impair the precision of the estimates and do not allow the results to be generalized. Paramedian anchorage in the anterior palate can be recommended for molar distalization but, given the great inter-individual variability of the palatal bone height, it must be preceded by reliable CT-based imaging in patients identified by routine investigations as being at risk.

Three-dimensional densitometric analysis of maxillary sutural changes induced by rapid maxillary expansion

OBJECTIVE

This prospective study evaluated the density of the midpalatal and transverse sutures as assessed by low-dose CT before rapid maxillary expansion (T0), at the end of active expansion (T1) and after a retention period of 6 months (T2).

METHODS

The study sample comprised 17 pre-pubertal subjects (mean age 11.2 years) with constricted maxillary arches. Total amount of expansion was 7 mm in all subjects. Multislice low-dose CT scans were taken at T0, T1 and T2. On the axial CT scanned images six regions of interest (ROIs) were placed along the midpalatal and transverse sutures and two in maxillary and palatal bony areas. Density was measured in Hounsfield units. Mann-Whitney U test and Friedman analysis of variance with post hoc tests were used (p < 0.05).

RESULTS

The three ROIs in the midpalatal suture showed a significant decrease in density from T0 to T1, a significant increase from T1 to T2 and a lack of statistically significant differences from T0 to T2. Both ROIs located in the transverse suture showed a significant decrease in density from T0 to T1, followed by a non-significant increase in density from T1 to T2.

CONCLUSIONS

At the end of the active phase of expansion a significant reduction in density along the midpalatal and transverse sutures was observed in all subjects. The sutural density of the midpalatal suture at T2 indicated reorganization of the midpalatal suture while the density along the transverse suture increased without reaching the pre-treatment values, possibly due to different morphology between midpalatal and transverse sutures.

Effects of surgically assisted rapid palatal expansion with and without pterygomaxillary disjunction on dental and skeletal structures: a retrospective review

OBJECTIVE

The aim of this study was to evaluate and compare dental and skeletal changes in surgically assisted rapid palatal expansion (SARPE) patients with (+PP) and without (-PP) pterygomaxillary disjunction.

STUDY DESIGN

The study casts of 18 maxillary constriction patients indicated for SARPE formed the sample of this retrospective review. The sample was divided into 2 groups. Twenty linear and 2 angular measurements were performed on the study models.

RESULTS

All transversal measurements increased after expansion in both the +PP and -PP groups. The -PP group showed greater expansion at the midpalatal and gingival levels, while the +PP group exhibited a greater increase of 0.78 mm at the apical base level and 11.25° less tipping in the molar teeth. A greater expansion of nearly 0.7 mm was measured in the premolar region of the +PP group.

CONCLUSIONS

Both SARPE techniques resulted in significant maxillary expansion.

The mouse palate and its cellular responses to midpalatal suture expansion forces

OBJECTIVES

To investigate the anatomy of the mouse palate, the midpalatal suture, and the cellular characteristics in the sutures before and immediately after midpalatal suture expansion.

MATERIALS AND METHODS

Wild-type C57BL/6 male mice, aged between 6 weeks and 12 months, were chosen for all the experiments. The complete palate of the non-operated group and the midpalatal suture-expanded group at different ages was used for histological, micro-CT, immunohistochemistry, and sutural cell analyses.

RESULTS

This study documents precise morphological and histological characteristics of the mouse palatal sutures. In addition to the opening of the midpalatal suture caused by expansion, both transverse and interpalatine sutures were also seen to be affected. Cellular density was decreased in different types of sutures following the application of mechanical force.

CONCLUSIONS

The detailed morphology and histology of the mouse palate and the cellular changes that occur following midpalatal suture expansion, as described here, will be helpful as a basis for further investigations of palatal suture tissue responses to mechanical force.

Upper molar distalization on palatal miniscrews: an easy to manage palatal appliance

Upper molar distalization supported by miniscrews has become increasingly popular in the last years. A detailed clinical and lab procedure for the realization of a distalization appliance (fast back or distal jet) connected to miniscrews inserted in the anterior region of the palate is presented. A case report illustrates the use of a fast back appliance supported by miniscrews to correct the mesial shift of the molars and of the premolars as a consequence of an early loss of the maxillary deciduous canines.