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

Transverse changes determined by rapid and slow maxillary expansion--a low-dose CT-based randomized controlled trial

OBJECTIVES

To compare transverse skeletal changes produced by rapid (RME) and slow (SME) maxillary expansion using low-dose computed tomography. The null hypothesis was that SME and RME are equally effective in producing skeletal maxillary expansion in patients with posterior crossbite.

SETTING AND SAMPLE POPULATION

This study was carried out at the Department of Oral Sciences, University of Naples Federico II, Italy. Twelve patients (seven males, five females, mean age ± SD: 10.3 ± 2.5 years) were allocated to the SME group and 14 patients (six males, eight females, mean age ± SD: 9.7 ± 1.5 years) to the RME group.

MATERIALS AND METHODS

All patients received a two-band palatal expander and were randomly allocated to either RME or SME. Low-dose computed tomography was used to identify skeletal and dental landmarks and to measure transverse maxillary changes with treatment.

RESULTS

A significant increase in skeletal transverse diameters was found in both SME and RME groups (anterior expansion = 2.2 ± 1.4 mm, posterior expansion = 2.2 ± 0.9 mm, pterygoid expansion = 0.9 ± 0.8 mm). No significant differences were found between groups at anterior (SME = 1.9 ± 1.3 mm; RME = 2.5 ± 1.5 mm) or posterior (SME = 1.9 ± 1.0 mm; RME = 2.4 ± 0.9 mm) locations, while a statistically significant difference was measured at the pterygoid processes (SME = 0.6 ± 0.6 mm; RME = 1.2 ± 0.9 mm, p = 0.04), which was not clinically relevant.

CONCLUSION

Rapid maxillary expansion is not more effective than SME in expanding the maxilla in patients with posterior crossbite.

Three-dimensional assessment of maxillary changes associated with bone anchored maxillary protraction

INTRODUCTION

Bone-anchored maxillary protraction has been shown to be an effective treatment modality for the correction of Class III malocclusions. The purpose of this study was to evaluate 3-dimensional changes in the maxilla, the surrounding hard and soft tissues, and the circummaxillary sutures after bone-anchored maxillary protraction treatment.

METHODS

Twenty-five consecutive skeletal Class III patients between the ages of 9 and 13 years (mean, 11.10 ± 1.1 years) were treated with Class III intermaxillary elastics and bilateral miniplates (2 in the infrazygomatic crests of the maxilla and 2 in the anterior mandible). Cone-beam computed tomographs were taken before initial loading and 1 year out. Three-dimensional models were generated from the tomographs, registered on the anterior cranial base, superimposed, and analyzed by using color maps.

RESULTS

The maxilla showed a mean forward displacement of 3.7 mm, and the zygomas and the maxillary incisors came forward 3.7 and 4.3 mm, respectively.

CONCLUSIONS

This treatment approach produced significant orthopedic changes in the maxilla and the zygomas in growing Class III patients.

The search for the ideal fixation of palatal fractures: innovative experience with a mini-locking plate

Fractures of the palate have defied conventional management, such that malrotation and disinclination of the palatal shelves occur in a significant number of patients after repair. The fractured palatal shelves of eight patients were first prealigned. To do so, one or more 205-mm ratchet clamps and two intermaxillary fixation (IMF) posts were used. Rigid fixation was then achieved by applying a 2.0-mm mini-locking titanium plate (across the palatal vault) and by applying an adaptation miniplate across the fracture line as it exited the anterior surface of the maxilla. Screws were passed directly through the mucoperiosteum, to engage the palatal shelves and to lock the locking plate into position. Lacerations in the mucoperiosteum were neither used to aid fixation nor used as portals for dissection; incisions and mucoperiosteal flaps in the palatal vault were avoided. Adjuncts, such as intraoral splints, have not been used in cases to date, and early mobilization was allowed. Reconstitution of the craniomaxillofacial buttresses was added in patients with more extensive maxillary injury. The palatal appliance and screws remained rigidly in position in the roof of the mouth, much like an external fixator, until their removal 8 to 12 weeks after the repair. No patient suffered erosion of the mucoperiosteum or other major morbidity, other than a transient fistula of the soft palate. The palatoalveolar segments remained in proper realignment and inclination, and pretraumatic occlusal patterns and the width and depth of the lower face appear to have been restored with one exception. The latter suffered a subtle posterolateral open bite that was corrected orthodontically. Prealignment of fractured palatal shelves with one or more large ratchet clamps and two IMF posts provides several points of forced reduction of the palatal shelves, along the dental arch. In addition, stabilization with mini-locking plate(s) in the palatal vault and an adaptation plate across the fracture line, as it exits the maxilla, appear to have merit, based on this preliminary report (n = 8). Outcomes seen on computed tomography and clinical examination during this 3-year experience have been favorable.

Evaluation of palatal bone density in adults and adolescents for application of skeletal anchorage devices

OBJECTIVES

To measure the cortical and cancellous bone densities of the palatal area in adolescents and adults and to compare bone quality among placement sites of temporary anchorage devices.

MATERIALS AND METHODS

One hundred twenty cone beam computerized tomography scans were obtained from 60 adolescents (mean age, 12.2 ± 1.9 years) and 60 adults (24.7 ± 4.9 years). The measurements of palatal bone density were made in Hounsfield units (HU) at 72 sites at the intersections of eight mediolateral and nine anterioposterior reference lines using InVivoDental software. Repeated-measures analysis of variance was used to analyze intragroup and intergroup differences.

RESULTS

The cortical and cancellous bone densities in the adults (816 and 154 HU, respectively) were significantly higher than those in the adolescents (606 and 135 HU; P < .001 and P  =  .032, respectively). However, the anterior portion of the cortical bone in adolescents had similar density values to the posterior portion of the cortical bone in adults. Gender comparison revealed that females had greater cortical bone densities (769 HU) than their male counterparts did (654 HU; P < .001).

CONCLUSIONS

Palatal bone densities were significantly higher in adults than in adolescents, and the anterior palatal areas of adolescents were of similar values to those at the posterior palate of adults.

Three-dimensional longitudinal evaluation of palatal vault changes in growing subjects

OBJECTIVE

To evaluate palatal vault change in children and to assess the reliability of two palatal parameters in assessing growth modifications.

SUBJECTS AND METHODS

A group of 26 healthy white children aged 5.3 ± 0.3 years (15 boys, 11 girls) were randomly selected. Impressions of the upper dental arches were obtained at baseline and at 12, 18, and 30 months follow-up. Three-dimensional digital images of study casts were obtained using a laser scanning device. Palatal surface area and palatal volume were measured on the digital study casts at each time point. Effect size (ES) coefficients were calculated for both parameters as indices of diagnostic reliability in individual subjects when at least equal to 1.0.

RESULTS

Significant increases in palatal surface area and volume were seen over the observation period (P < .001). ES coefficients for palatal surface area were greater than those for palatal volume. However, even for the former parameter, only the value taken at 30 months was above the threshold.

CONCLUSIONS

Growth of the palatal vault was significant during the observation period, which coincides with primary and mixed dentition stages. Palatal surface area appears to be more reliable than palatal volume in assessment of growth modifications in individual subjects.

Measurement of the midpalatal suture width

OBJECTIVE

To conduct a pilot study to investigate the potentiality to determine the midpalatal sutural width radiographically with a flat-panel volume computed tomography (fpVCT) in a porcine model.

MATERIALS AND METHODS

Bone samples from the midpalatal suture of five young (16 weeks) and five old (200 weeks) sus scrofa domestica were gathered. The midpalatal suture width was measured via fpVCT and compared to respective histological preparations. Results with P < .05 were considered significant.

RESULTS

The data obtained by fpVCT and by histomorphometric analysis reveal a highly significant age dependency of the measured suture width (both P < .0001), with lower suture width values in older subjects compared to the younger group. The averaged suture widths measured in the fpVCT images shows a distinctively higher mean compared to the histomorphometric data with high statistical significance (P < .0001). The evaluated difference between both methods was almost constant.

CONCLUSION

fpVCT is a powerful tool for determining midpalatal sutural width.

Periodontal effects of surgically assisted rapid palatal expansion evaluated clinically and with cone-beam computerized tomography: 6-month preliminary results

INTRODUCTION

Transverse maxillary deficiency is frequently observed in patients who seek orthodontic treatment. In skeletally mature patients, transverse maxillary deficiency can be treated with surgically assisted rapid palatal expansion (SARPE). Forces delivered by the expander produce areas of compression in the periodontal ligament, which could lead to alveolar bone resorption and possible changes in the attachment level. The aim of this prospective clinical study was to evaluate the periodontal effects of SARPE by means of a complete clinical evaluation and cone-beam computerized tomography (CBCT) evaluation.

METHODS

The sample included 14 patients (5 males, 9 females), with a mean age of 23.0 ± 1.9 years (range: 16.4 to 39.7 years). All patients were treated using a bonded Hyrax-type expander, and the mean expansion was 9.82 mm (7.5 to 12.0 mm). All patients had a 1-year retention period. CBCT scans were taken, and periodontal charts were completed at time points T0 (initial) and T1 (6 months after expansion).

RESULTS AND DISCUSSION

SARPE seemed to have little detrimental clinical effects on the periodontium. Radiographic data demonstrated statistically significant changes: a significant decrease in the buccal alveolar bone thickness on most teeth, a significant increase in the palatal alveolar bone thickness on most teeth, a decrease in the buccal alveolar crest level of all canines and posterior teeth, and a tendency toward a decrease in the interproximal alveolar crest level on the mesial aspect of both central incisors.

CONCLUSIONS

SARPE seems to have little detrimental effects on the periodontium clinically. However, radiographic data demonstrated some statistically significant changes, which could eventually have a significant clinical impact on the periodontium.

Three-dimensional evaluation of early crossbite correction: a longitudinal study

The aim of this longitudinal study was to assess whether correction of unilateral posterior crossbite in the primary dentition results in improvement of facial symmetry and increase of palatal surface area and palatal volume. A group of 60 Caucasian children in the primary dentition, aged 5.3 ± 0.7 years, were collected at baseline. The group consisted of 30 children with a unilateral posterior crossbite with midline deviation of at least 2 mm (CB) and 30 without malocclusion (NCB). The CB group was treated using an acrylic plate expander. The children's faces and dental casts were scanned using a three-dimensional laser scanning device. Non-parametric tests were used for data analysis to assess differences over the 30 months period of follow-up. The CB children had statistically significantly greater facial asymmetry in the lower part of the face (P < 0.05) and a significantly smaller palatal volume (P < 0.05) than the NCB children at baseline. There were no statistically significant differences between the two groups at 6, 12, 18, and 30 months follow-ups. Treatment of unilateral posterior crossbite in the primary dentition period resulted in an improvement of facial symmetry in the lower part of the face (P < 0.05) and increase of the palatal surface area and palatal volume (P < 0.001). At 30 months, relapse was observed in eight children (26.7 per cent). Treatment of unilateral posterior crossbite in the primary dentition improves facial symmetry and increases the palatal surface area and the palatal volume, though it creates normal conditions for normal occlusal development and skeletal growth.

Ossification of the midpalatal suture after surgically assisted rapid maxillary expansion

The purpose of this study was to evaluate ossification of the midpalatal suture in adult patients immediately after surgically assisted rapid maxillary expansion (SARME) until 120 days post-surgery. The sample comprised 126 standardized occlusal radiographs of 21 adults (14 females and 7 males; mean age: 25.33 years) taken pre-expansion (T1), immediately after expansion (T2), and post-expansion (30, 60, 90, and 120 days of retention, respectively: T3, T4, T5, and T6) who had undergone SARME. The radiographs were digitized and the images were analysed and compared in relation to the morphology and radiopacity at the different treatment stages, especially concerning the characteristics of the midpalatal suture. Data were statistically analysed using analysis of variance and Tukey's test. The results demonstrated that from T2 to T6, the mean optical density (OD) increased. However, these values were not similar to those observed at T1. A retention period of 120 days was not sufficient for the re-establishment of OD and complete ossification within the suture in the evaluated patients.

Surgical management of transverse maxillary deficiency in adults

Transverse maxillary deficiencies are a common occurance, prevalent in both syndromic and non syndromic patients. Treatment usually combines a orthodontic-surgical intervention in adults. This article reviews the procedures along with the experience of the authors in the correction of maxillary transverse deficiency in adults.

Miniscrew-assisted nonsurgical palatal expansion before orthognathic surgery for a patient with severe mandibular prognathism

A transverse maxillary deficiency in an adult is a challenging problem, especially when it is combined with a severe anteroposterior jaw discrepancy. The demand for nonsurgical maxillary expansion might increase as patients and clinicians try to avoid a 2-stage surgical procedure-surgically assisted rapid palatal expansion followed by orthognathic surgery-and detrimental periodontal effects and relapse. In this regard, a miniscrew-assisted rapid palatal expansion was devised and used to treat a 20-year-old patient who had severe transverse discrepancy and mandibular prognathism. Sufficient maxillary orthopedic expansion with minimal tipping of the buccal segment was achieved preoperatively, and orthognathic surgery corrected the anteroposterior discrepancy. The periodontal soundness and short-term stability of the maxillary expansion were confirmed both clinically and radiologically. Effective incorporation of orthodontic miniscrews for transverse correction might help eliminate the need for some surgical procedures in patients with complex craniofacial discrepancies by securing the safety and stability of the treatment, assuming that the suture is still patent.

Comparison of a modified RME appliance with other appliances for transverse maxillary expansion

AIM

Plate appliances or fixed appliances for transverse expansion are used to treat lateral crossbites in early mixed dentition. The aim of this study was to compare these appliances' dentoalveolar effects with those of a modified appliance with altered anchorage.

PATIENTS AND METHODS

Forty patients with early mixed dentition were examined. Twenty patients in the study group were treated with a modified RME appliance firmly anchored to the first permanent molars and with palatal rests in the first and second deciduous molar region. The appliance had wire extensions to the palatal aspects of the canines. One of the two comparison groups comprised 10 patients whose maxillary dental arch was transversally expanded with a split-plate appliance, and the other group contained 10 patients treated with a Hyrax-type rapid palatal expander fixed to the first permanent molars. After the plaster casts' transverse parameters before and after expansion and after retention were measured to ascertain the treatment result, statistical analysis was performed applying the Wilcoxon test and Mann-Whitney U test.

RESULTS

The modified RME appliance expanded the anterior and posterior arch width highly significantly in transversal direction (p < 0.001). At the end of the retention phase, there were no significant differences between the modified RME appliance and the RME appliance with shortened arms. Compared to the split-plate appliance, the modified RME (p < 0.05) expanded the anterior arch width significantly.

CONCLUSION

The modified RME appliance can be used effectively for rapid maxillary expansion in the early mixed dentition. At the end of the retention phase, the overall effect of the modified appliance is similar to that of the other methods.

Effect of low-level laser therapy (GaAlAs) on bone regeneration in midpalatal anterior suture after surgically assisted rapid maxillary expansion

OBJECTIVE

The aim of this study was to evaluate the effects of laser therapy on bone regeneration in the midpalatal anterior suture (MPAS) after surgically assisted rapid maxillary expansion (SARME).

METHODS

Thirteen patients aged between 18 and 33 years old with maxillary transverse deficiency (> or =7.0 mm) were evaluated. All patients underwent subtotal Le Fort I osteotomy with separation of the pterygomaxillary suture with the use of Hyrax expander, and were divided into 2 groups: control group (n = 6) and laser group (n = 7). A GaAlAs laser (P = 100 mW, lambda = 830 nm, Ø = 0.06 cm(2)) was used. The laser was applied in 8 treatment sessions with intervals of 48 hours. Each treatment session consisted of laser applications, per point (E = 8.4J, ED = 140J/cm(2)), at 3 points on the MPAS, and total dose of E = 25.2 J, ED = 420 J/cm(2). Digital radiographs were taken before the surgical procedure and at 1-, 2-, 3-, 4-, and 7-month follow-up visits. Optical density analysis of the regenerated bone was performed using Adobe Photoshop 8.0 software.

RESULTS

Bone regeneration associated with the use of laser after SARME showed a statistically significant difference. A higher mineralization rate was found in the laser group (26.3%, P < .001) than the control group.

CONCLUSION

Low-level laser irradiation (GaAlAs) accelerates bone regeneration in MPAS after SARME. However, the optical density measurements after 7 months of follow-up were lower in comparison with the preoperative measurements.

Palatal volume following rapid maxillary expansion in mixed dentition

OBJECTIVE

To evaluate volumetric variations in the palate following rapid expansion, both immediately after treatment and over time.

MATERIALS AND METHODS

The sample was composed of 30 patients in early mixed dentition treated with a Haas-type device cemented onto the primary second molars. The mean age of the patients upon commencement of expansion was 7 years and 6 months (standard deviation [SD], 12 months). Measurement of palatal volume was conducted via 3D acquisition of plaster models using laser scanning before treatment (T1), upon device removal (T2), and 2.6 years afterward (T3).

RESULTS

The volume of the palate increased in a statistically significant fashion from T1 to T2 and from T1 to T3, and it decreased in a nonsignificant fashion from T2 to T3.

CONCLUSIONS

Palatal volume significantly increases with rapid maxillary expansion (RME) treatment with insignificant relapse. The use of virtual 3D models with the aid of Apposite software permits evaluation of the morphologic and volumetric changes induced by orthodontic treatment.

Effect of timing on the outcomes of 1-phase nonextraction therapy of Class II malocclusion

INTRODUCTION

The aim of this cephalometric study was to evaluate the role of timing in relation to skeletal maturity on the outcomes of nonextraction comprehensive Class II therapy.

METHODS

Three samples of patients with Class II Division 1 malocclusion were treated with headgear combined with fixed appliances and Class II elastics. Lateral cephalograms were taken of all subjects before therapy (T1) and at an average interval of 6 months after therapy (T2). The first sample (23 subjects) was treated before the pubertal growth spurt, the second sample (24 subjects) received therapy during the pubertal growth spurt, and the third sample (13 subjects) was treated at a postpubertal stage of development. The average T1 to T2 interval was approximately 30 months for all patients, with an average treatment duration of 24 months. Longitudinal observations of a group of 17 subjects with untreated Class II malocclusions were compared with the treated groups at the 3 skeletal maturation intervals with nonparametric statistics.

RESULTS

Class II treatment before or during the pubertal growth spurt induced significant favorable skeletal changes (restricted maxillary advancement in prepubertal patients and enhanced mandibular growth in pubertal patients). Patients treated after the pubertal growth spurt had only significant dentoalveolar changes.

CONCLUSIONS

The greatest amount of dentoskeletal correction of Class II malocclusion with 1-phase nonextraction treatment occurred in patients treated during the pubertal growth spurt.

Cephalometric study of slow maxillary expansion in adults

INTRODUCTION

The purpose of this retrospective study was to evaluate the dentoskeletal changes after slow maxillary expansion in adults.

METHODS

Three kinds of maxillary expanders (Haas [Dyna Flex, Laboratory, St Louis, Mo], MAX-2000 [Dyna Flex], and DMAX-2000 [Dyna Flex]) were used randomly in 3 study groups of 65 adults treated with nonsurgical slow maxillary expansion, followed by full straight-wire appliance therapy. A control group of 22 adults, meeting the same inclusion criteria, were treated only with full straight-wire appliance therapy without expansion. Posteroanterior and lateral cephalometric records were taken before the start of treatment (T1) and after fixed orthodontic treatment (T2). The data were analyzed statistically by using paired t tests and Kruskal-Wallis H tests.

RESULTS

From T1 to T2, there was no significant change in nasal width, maxillary width, and mandibular width in the 3 groups. The sella-nasion-mandibular plane angle increased 0.97 degrees (P <0.05) in the DMAX-2000 group. The mandibular incisor-mandibular place angle in the Haas, MAX-2000, DMAX-2000, and control groups had mean increases of 4.90 degrees, 4.42 degrees, 4.55 degrees, and 5.20 degrees (P <0.05 for each), respectively. The maxillary incisor-nasion-A-point angle increased 3.04 degrees (P = 0.05), and the distal root of the maxillary first molar-nasion perpendicular decreased 1.48 mm (P <0.05) in the control group. The distal facet of the maxillary first molar-nasion perpendicular decreased 3.57 mm (P <0.05), and the distal root of the maxillary first molar-nasion perpendicular decreased 2.50 mm (P <0.05) in the MAX-2000 group.

CONCLUSIONS

After expansion treatment, there were no evident transverse or significant sagittal and vertical skeletal maxillary changes in the 3 groups.

Treatment response and stability of slow maxillary expansion using Haas, hyrax, and quad-helix appliances: a retrospective study

INTRODUCTION

In this retrospective study, we evaluated the short- and long-term effects of slow maxillary expansion with Haas, hyrax, and quad-helix appliances on posterior crossbite (PXB) correction stability, and maxillary intermolar width and angulation, in the deciduous or early mixed dentition.

METHODS

The inclusion criteria were models and treatment notes of patients with PXB at the start of treatment (T1), after PXB correction (T2), and at least 2 years posttreatment (T3). Exclusion criteria were craniofacial anomalies, fixed appliance use, or more than 1 expander type. From 312 consecutive expansion patients, 74 Haas, 41 hyrax, and 45 quad-helix subjects were evaluated regarding PXB correction, intermolar width, and angulation and compared with published norms to separate treatment effects from growth. The mean ages at T1, T2, and T3 were 8, 9, and 13 years.

RESULTS

There were no significant differences in PXB correction stability or treatment response at T2 and T3 among the 3 expanders. Expansion increased intermolar width by 5 mm and tipped each molar by 2.3 degrees. At least 2 years after expander removal, molar width decreased by 1.3 mm, and the molars uprighted by 6 degrees. Compared with noncrossbite norms, PXB subjects had narrower intermolar width before treatment and greater width after expansion, and were slightly wider at least 2 years posttreatment. Both younger age at T1 and retainer use resulted in statistically greater intermolar width at T3.

CONCLUSIONS

Eighty-four percent of PXB correction remained with about one third of the initial expansion lost; retainer use and early treatment provided increased intermolar width. Haas, hyrax, and quad-helix appliances were equally effective. Slow maxillary expansion altered the PXB patients' maxillary widths from narrower to slightly wider than the widths of the noncrossbite norms.

Orthodontic or surgically assisted rapid maxillary expansion

PURPOSE

The purpose of this study was to present, compare, and discuss the techniques for rapid maxillary expansion.

DISCUSSION

The isolated transverse maxillary deficiency can be treated either orthodontically or surgically with rapid palatal expansion. In children and adolescents, conventional orthodontic rapid maxillary expansion has been successful when used before sutural closure. On the other hand, in skeletally mature patients, the possibility of successful maxillary expansion decreases as sutures close and the resistance to mechanical forces increases.

CONCLUSIONS

The selection of an expansion technique depends on a number of factors. It is more likely to advocate surgery as the patient's age, transverse needs, or acceptance of the idea of surgery increases.

Evaluation of surgically assisted rapid maxillary expansion with or without pterygomaxillary disjunction based upon preoperative and post-expansion 3D computed tomography data

PURPOSE, METHODS: This study (50 patients; Ø 25 years) compared surgically assisted rapid maxillary expansion (SARME) with (+/-PP) to SARME without pterygomaxillary (-PP) disjunction due to dentoskeletal effects in 3D CT preoperatively and Ø 11 weeks post-expansion.

RESULTS

In t test, SARME-PP declined in transverse width from anterior to posterior but more symmetrically than SARME+PP. It produced more segmental inclination and vestibular bone resorption in the premolars. SARME+PP also declined in transverse width from anterior to posterior but more asymmetrically with an extreme convergence to the molars. It produced more segmental inclination and vestibular bone resorption (second molar) in the molars and a palatal bone plate thickness increase in the second premolar. With variance analysis, a further differentiation between the two independent groups due to secondary variables was made: SARME+PP produced the biggest decline in transverse width (patients <20 years) and the biggest segmental outward inclination from anterior to posterior in patients with bone-borne devices. SARME-PP in patients <20 years and SARME+PP in patients >20 years both produced the biggest lateral pterygoid bending.

CONCLUSION

Pterygomaxillary disjunction should be based on patient age and individual requirements, i.e., in patients <20 years (SARME-PP) and >20 years (SARME+PP).

Long term effects of surgically assisted rapid maxillary expansion without performing osteotomy of the pterygoid plates

PURPOSE

Surgically assisted rapid maxillary expansions (SARME) are commonly used to widen the maxilla. This study evaluates long term stability of surgically assisted rapid palatal expansion without performing osteotomy of the pterygoid plates and its effects on nasal airway volume.

MATERIALS AND METHODS

13 patients (mean age 31, 23+/-6, 11) with a maxillary transverse deficit of at least 5mm were examined 1 month before and on average 63 months after a mean palatal distraction of 8.29+/-1.68mm by acoustic rhinometry. Profiles of the nasal airway volumes were collected. A cast model analysis was performed. The data were evaluated using Wilcoxon signed rank test.

RESULTS

A V-shaped movement of the segments was observed. The gain for total nasal volume was 23.25%. Findings indicate a significant enhancement of nasal volume in all patients (P<0.01) as result of the maxillary expansion. No relapse occurred in the study group.

CONCLUSION

SARME provides a long term stable orthodontic bite correction and permanently enhances the nasal airways. A transverse shift of the segments can be achieved over the whole bony palate even when no osteotomy of the pterygo-maxillary suture is performed.

Bone quality in the midpalate for temporary anchorage devices

OBJECTIVE

The aim of the present study was to quantitatively assess the bone quality of the palatal bone from an implantologic standpoint.

MATERIAL AND METHODS

The material consisted of palatal tissue blocks of autopsy material from 22 subjects (19 male, three female), between 18 and 63 years of age. The specimens comprised the anterior part of median palate (APMP) from about 7 mm behind the incisive foramen (first premolar regions), the middle part of median palate (MPMP, second premolar region), and the posterior part of the median palate (PPMP, first molar region). They were prepared in the transversal plane using ground-thin-section technology. The midpalatal areas of the different parts of the palate [regions of interest (ROI) for temporary anchorage device (TAD) placement] 3 mm bilaterally to the midline were assessed with respect to hard tissue fraction to total bone volume (HTF/TBV), bone marrow fraction to total bone volume (BMF/TBV), and sutural tissue fraction to total bone volume (STF/TBV). Furthermore, age-specific evaluation was performed: younger age group (18-25 years, n=10) and older age group (26-63 years, n=12).

RESULTS

Histomorphometric measurement showed the following results for the APMP: mean HTF/TBV, 68.57%; mean BMF/TBV, 21.38%; and mean STF/TBV, 9.96%. There were no statistically significant differences between the various tissue fractions of the APMP, MPMP, and PPMP. The younger age group showed a mean HTF/TBV of 68.88%, a mean BMF/TBV of 21.5%, and a mean STF/TBV of 9.53%. No statistically significant differences with the older age group were found.

CONCLUSION

These results suggest that the HTF in the APMP, MPMP, and PPMP in younger as well as older adults is relatively high. Thus, good primary stability of TADs should be achieved in all parts of the adult median palate independent of age.

Anatomic site evaluation of the palatal bone for temporary orthodontic anchorage devices

OBJECTIVES

The aim of the present study was to assess the micromorphologic characteristics of the palatal bone from an implantologic standpoint.

MATERIALS AND METHODS

The material consisted of tissue blocks of autopsy material from 22 subjects (18 males, three females) between 18 and 63 years of age. The specimens comprised the anterior median palatal region from 5 to 10 mm behind the incisive foramen. They were prepared in the transversal plane according to ground thin-section technology. The midpalatal area as well as an area of 3 mm bilateral to the midline were assessed, and a classification of quantitative palatal bone availability was developed.

RESULTS

The findings could be divided into three classes: (1) class I palatal bone consists almost of compact bone; (2) class II cortical bone layer on oral and nasal sides of palate, broad compact bone in the suture area (>or=3 mm), loose trabecular bone lateral to the suture area; and (3) class III cortical bone on oral and nasal side, thin compact bone in the suture area (<3 mm) and loose-structured trabecular bone lateral to the suture area. In most sections (72.7%), class I characteristics were found (16 subjects). 18.2% of sections were assigned to class II (four subjects) and only 9.1% of sections were assigned to class III (two subjects).

CONCLUSION

These results document that in most cases a good primary stability of temporary orthodontic anchorage devices should be achieved in the midpalatal and paramedian area of the anterior palate, as the bone quantity available is high.

Palatal implants in adolescents: a histological evaluation in beagle dogs

OBJECTIVES

Small osseointegrated implants inserted in the palate provide a reliable anchorage control during orthodontic treatment. When these implants are inserted in the median palatal suture in adolescents, there might be interference with normal transverse development of the maxilla. The aim of this study was to determine histometrically the influence of implants inserted in the median palatal suture in adolescent beagle dogs on transverse maxillary development and to determine the amount of osseointegration of unloaded palatal implants in the median palatal suture in adolescent beagle dogs.

MATERIAL AND METHODS

Two palatal implants were inserted in the median palatal suture in four of five adolescent beagle dogs. The experimental period took 25 weeks, and the dogs were subjected to a scheme of sequential point labelling with vital stains every 6 weeks. Insertion sites were examined microscopically and histometric analysis was performed.

RESULTS AND DISCUSSION

Both anterior width and posterior width were wider in the control dog as compared with the average in the test dogs, 3.7% and 9.5%, respectively. After loss of a palatal implant, immediate repair of the bone in the suture area could be observed. In the posterior region, the repaired suture looked more like a suture in the infantile stage in humans, instead of having a sinusoidal course, as was observed in the control dog and in adolescent humans. The amount of osseointegration varied from 43% to 64.3%.

CONCLUSION

The results of this study support the idea that in adolescents, palatal implants should not be inserted in the median palatal suture because of possible growth impairment (transverse maxillary development). The amount of osseointegration of unloaded palatal implants in the median palatal suture in adolescent dogs is less as compared with dental implants in dogs and loaded palatal implants in adult humans.

Surgically assisted rapid palatal expansion: a literature review

Transverse maxillomandibular discrepancies are a major component of several malocclusions. Orthopedic and orthodontic forces are used routinely to correct a maxillary transverse deficiency (MTD) in a young patient. Correction of MTD in a skeletally mature patient is more challenging because of changes in the osseous articulations of the maxilla with the adjoining bones. Surgically assisted rapid palatal expansion (SARPE) has gradually gained popularity as a treatment option to correct MTD. It allows clinicians to achieve effective maxillary expansion in a skeletally mature patient. The use of SARPE to treat MTD decreases unwanted effects of orthopedic or orthodontic expansion. Our aim in this article is to present a comprehensive review of the literature, including indications, diagnosis, guidelines for case selection, a brief overview of the surgical techniques, orthodontic considerations, complications, risks, and limitations of SARPE to better aid the clinician in the management of MTD in skeletally mature patients.

Radiographic and microscopic anatomy of the mid-palatal suture in the elderly

In a previous radiological study of the mid-palatal suture, it has been demonstrated that its obliteration was occurring during adult life and varied. In order to determine the histological status of mid-palatal suture in elderly men, 20 human palates aged more than 70 were examined by occlusal radiographs and histological study of the suture. In all palates the suture was ossified in the anterior thirds and made of conjunctive tissue in the posterior third. This particular evolution could be correlated to the mastication forces acting on the maxillary bones during the entire life.