Palatal Bone Research Articles

Effectiveness of iliac cancellous bone grafting in alveolar cleft repair and analysis of factors affecting it.

To review the effectiveness of secondary alveolar bone grafting using iliac cancellous bone in patients with unilateral complete alveolar cleft and to investigate the factors influencing it. A retrospective study of 160 patients with unilateral complete alveolar clefts who underwent iliac cancellous bone graft repair at the Department of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, was conducted. Eighty patients in the young age group (6-12 years) and 80 in the old age group (≥13 years) were included. Bone bridge formation was determined using Mimics software, and the volume was measured to calculate the iliac implantation rate, residual bone filling rate, and resorption rate. The factors that affected bone grafting in both subgroups were investigated. Using bone bridge formation as the clinical success criterion, the success rate for the entire population was 71.25%, with a significant difference of 78.75% and 63.75% for the young and old age groups, respectively (P=0.036). The gap volume in the latter was significantly larger than that in the former (P<0.001). The factors that influenced bone grafting in the young group were the palatal bone wall (P=0.006) and history of cleft palate surgery (P=0.012), but only the palatal bone wall affected the outcome in the old age group (P=0.036). The results of alveolar bone grafting for the old age group were worse than those for the young age group. The palatal bone wall was an important factor that affected alveolar bone grafting, and alveolar bone grafting in the young patients was influenced by the history of cleft palate surgery.

Clinical analysis of successful insertion of orthodontic mini-implants in infrazygomatic crest

BackgroundThe insertion positions of mini-implant in infrazygomatic crest has been reported, but due to the anatomical variation, the precise location of this site is not clear yet. This study used cone-beam computed tomography (CBCT) to analyze the position and angle of mini-implants successfully inserted in the infrazygomatic crest, with the goal of providing reference data for clinical practice.MethodsCBCT was used to image 40 mini-implants and their surrounding tissues in adult orthodontic patients who successfully underwent mini-implant insertion in the infrazygomatic crest. The insertion positions and angles of mini-implants were measured, and the thicknesses of buccal and palatal bone adjacent to the mini-implants were also recorded. Then, we proposed the position and implantation angle for infrazygomatic crest insertion. According to the position and angle, the cortical bone thickness and distance to the root of another 54 randomly selected infrazygomatic crests were recorded to verify its feasibility.ResultsIn the coordinate system, the implantation position of the 40 successful mini-implants was (-0.4 ± 2, 8.2 ± 2.5) and the implantation angle between the long axis of the mini-implant and horizontal reference plane was 56.4° ± 7.7°. The bone thicknesses on buccal and palatal sides of infrazygomatic crest adjacent to mini-implants were 4.1 ± 2.5 mm and 7.2 ± 3.2 mm, respectively, and the cortical bone thickness was 2.4 ± 0.6 mm. Among 54 infrazygomatic crests, 75.9% of them met the safety and stability requirements. When the implantation height was increased by 1, 2, and 3 mm, the proportions of implants that met requirements for success were 81.5%, 90.7%, and 94.4%, respectively. But, the proportions of eligible implants were limited at implantation angle increases of 5° and 10°.ConclusionsUsing the long axis of the maxillary first permanent molar (U6) as the vertical reference line, mini-implants could be safely inserted in the infrazygomatic crest at a distal distance of 0.4 mm and height of 8.2 mm from the central cementum-enamel junction of U6, with an implantation angle of 56.4°. The success rate increased when the implant height increased, but the proportion of eligible implantation was limited with the increase of implantation angle.

Stability of maxillary expansion osteotomy using patient-specific fixation implants without necessitating removable appliances: a retrospective analysis.

This study aimed to evaluate the long-term stability of surgical maxillary expansion using patient-specific fixation implants (PSFIs) without intraoral retention. Fifteen patients who had undergone segmented Le FortI osteotomy and PSFIs with available preoperative (t0) early (t1) and 1-year follow-up computed tomography (CT) scans (t2) were evaluated. The early and 1-year 3D models were superimposed to transfer the bony landmarks; the distances between each pair of landmarks at the different time points were then measured. The distances between the canines and second molars were also measured directly on the CTscans. The achieved maxillary expansions ranged from a median of 4.39 (2.00-6.27) mm at the greater palatine foramina to a median of 2.14 (1.56-2 > 83) mm at the canine level of the palatal bone. One year postoperatively, the changes in skeletal diameters ranged from a median of - 0.53 (- 1.65 to 0.41) mm at the greater palatine foramina (p = 0.12) to 0.17 (- 0.09 to 0.32) mm at the canine level of the palatal bone (p = 0.56). Changes in dental arch diameters ranged from a median of - 0.6 (- 2 to 0.00) mm between the second molars to - 1.3 (- 1.8 to - 0.25) mm between the canines (P < 0.05). This study showed the stability of maxillary expansion osteotomy using PSFIs, even without postoperative intraoral retention. PSFIs are a reliable method for the surgical treatment of transverse maxillary discrepancy. PFSIs are easy-to-use and improve surgical accuracy.

Morphometric Comparison of the Maxillary Alveolar Ridge Profile at Lateral Incisor and Premolar Tooth Regions Using Cone Beam Computed Tomography: A Cross-sectional Comparative Study

Comprehensive pre-surgical evaluation, proper radiographic examination and careful surgical intervention are necessary for long-term success of implants. This study highlights the importance of assessment of morphometric dimensions of alveolar ridge profile at the maxillary lateral incisor and premolar using cone beam computed tomography (CBCT) thereby reducing the complications during the clinical procedures like implant placement, mini-implants in orthodontic anchorage, para-endodontic surgeries.&#x0D; A total of 58 CBCT scans were included in the study and divided into two groups. (group-A, 20-35 years; group-B, 36-50 years). The buccal and palatal thickness of the maxillary alveolar cortical plates were measured at the crest, mid root, mid alveolar housing area, and the apex of the root.&#x0D; In the sample of 58 CBCTs, the cortical plate thickness at the crest of the premolars has a significant increased thickness when compared to the lateral incisor in both the age groups. The thickness of mid alveolar housing point of premolars has significant increased thickness than the lateral incisors of age group-B.&#x0D; In this study, the recommendations based on the results were beneficial in providing information regarding the buccal and palatal bone thickness at the maxillary lateral incisor and premolar tooth regions in 21-35 years and 36-50 years age groups thereby preventing complications that occur while undergoing dental procedures.

Oral and Maxillofacial Radiology

Clinically (Figure 1) a unilateral swelling, proptosis and obliteration of the nasolabial fold was noted. Intraoral examination revealed normal-appearing overlying mucosa. A pantomograph (Figure 2) demonstrates a mixed diffuse expansile lesion and thinning of the cortices affecting both jaws. 3D reconstruction (Figure 3) overview the lesions' extent. CBCT interpretation (Figures 4 and 5) indicated engrossment of the frontal, parietal, temporal, sphenoid, ethmoid, maxillary, palatine, zygomatic, and mastoid bones. T1-weighted gadolinium-enhanced MRI image (Figure 6) of a patient with a similar lesion in the right maxilla demonstrates a heterogeneous appearance.

Influence of buccal and palatal bone thickness on post-surgical marginal bone changes around implants placed in posterior maxilla: a multi-centre prospective study

BackgroundNumerous clinical variables may influence early marginal bone loss (EMBL), including surgical, prosthetic and host-related factors. Among them, bone crest width plays a crucial role: an adequate peri-implant bone envelope has a protective effect against the influence of the aforementioned factors on marginal bone stability. The aim of the present study was to investigate the influence of buccal and palatal bone thickness at the time of implant placement on EMBL during the submerged healing period.MethodsPatients presenting a single edentulism in the upper premolar area and requiring implant-supported rehabilitation were enrolled following inclusion and exclusion criteria. Internal connection implants (Twinfit, Dentaurum, Ispringen, Germany) were inserted after piezoelectric implant site preparation. Mid-facial and mid-palatal thickness and height of the peri-implant bone were measured immediately after implant placement (T0) with a periodontal probe and recorded to the nearest 0.5 mm. After 3 months of submerged healing (T1), implants were uncovered and measurements were repeated with the same protocol. Kruskal-Wallis test for independent samples was used to compare bone changes from T0 to T1. Multivariate linear regression models were built to assess the influence of different variables on buccal and palatal EMBL.ResultsNinety patients (50 females, 40 males, mean age 42.9 ± 15.1 years), treated with the insertion of 90 implants in maxillary premolar area, were included in the final analysis. Mean buccal and palatal bone thickness at T0 were 2.42 ± 0.64 mm and 1.31 ± 0.38 mm, respectively. Mean buccal and palatal bone thickness at T1 were 1.92 ± 0.71 mm and 0.87 ± 0.49 mm, respectively. Changes in both buccal and palatal thickness from T0 to T1 resulted statistically significant (p = 0.000). Changes in vertical bone levels from T0 to T1 resulted not significant both on buccal (mean vertical resorption 0.04 ± 0.14 mm; p = 0.479) and palatal side (mean vertical resorption 0.03 ± 0.11 mm; p = 0.737). Multivariate linear regression analysis showed a significant negative correlation between vertical bone resorption and bone thickness at T0 on both buccal and palatal side.ConclusionThe present findings suggest that a bone envelope > 2 mm on the buccal side and > 1 mm on the palatal side may effectively prevent peri-implant vertical bone resorption following surgical trauma.Trial RegistrationThe present study was retrospectively recorded in a public register of clinical trials (www.clinicaltrials.gov - NCT05632172) on 30/11/2022.

Management of an adult patient with severe crowding using lingual appliances and mini-screw anchorage: A case report

At present, more adult patients seek orthodontic treatment so orthodontists are more likely to face periodontal patients and esthetic appliance demand increases. This case report presents the management of an adult patient with mild periodontitis and severe crowding using lingual appliances and mini-screw anchorage. Interproximal stripping was performed to create space and correct the triangular tooth shape and gingival black triangles. Four mini-screws were implanted in the palatal alveolar bone and mandibular buccal shelf to distalize the entire upper and lower arch. According to the case report, interproximal stripping in combination with mini-screw-assisted entire arch distalization and lingual appliances may be an effective space-creation approach in patients treated with non-extraction way.

The LRP5 high-bone-mass mutation causes alveolar bone accrual with minor craniofacial alteration.

Mutations in low-density lipoprotein receptor-related protein 5 (LRP5) cause various bone diseases. Several mouse models were generated to study the role of LRP5 in bone development. But most of the studies were confined to the appendicular skeleton. The role of LRP5 in the axial skeleton, especially in the craniofacial skeleton, is largely unknown. The aim of this study was to investigate the craniofacial phenotype with the LRP5G171V mutation. To understand how LRP5 affects craniofacial bone properties, we analyzed LRP5 high-bone-mass mutant mice carrying the G171V missense mutation (LRP5HBM ). Quantitative microcomputed tomographic imaging and histomorphometric analyses were used to study craniofacial phenotypes and bone density. Histology, immunohistochemistry, and in vivo fluorochrome labeling were used to study molecular mechanisms. LRP5HBM mice showed overall minor changes in the craniofacial bone development but with increased bone mass in the interradicular alveolar bone, edentulous ridge, palatine bone, and premaxillary suture. Elevated osteocyte density was observed in LRP5HBM mice, along with increased Runx2 expression and unmineralized bone surrounding osteocytes. Meanwhile, LRP5HBM mice exhibited increased osteoprogenitors, but no significant changes were observed in osteoclasts. This led to a high-bone-mass phenotype, and an increased osteocyte density in the alveolar bone and edentulous ridge. LRP5HBM mice display increased bone mass in the alveolar bone with minor changes in the craniofacial morphology. Collectively, these data elucidated the important role of LRP5 in axial bone development and homeostasis and provided clues into the therapeutical potential of LRP5 signaling in treating alveolar bone loss.

Novel Custom Maxillary Disimpaction Splint.

LeFort I, II, and III osteotomies are commonly used in complex craniofacial reconstruction. Patients requiring these procedures typically have a craniofacial cleft, other congenital craniofacial deformities, or severe facial trauma. Both the cleft and traumatized palate have poor bony support, which leads to possible complications when the disimpaction forceps are used during the downfracture of the maxilla. Such potential complications include trauma or formation of a fistula of the palatal, oral, or nasal mucosa; trauma to adjacent teeth; and fracture of the palate and alveolar bone. To help prevent these complications, we developed a custom disimpaction splint. The splint is designed to cover the palate and occlusal surfaces to increase retention and minimize splint movement during the maxillary downfracture portion of the surgical procedure. The base of the splint is fabricated from a two-layered biocryl material, and the palatal area is built with soft-cushion rebase material. This allows for a stable grip of the disimpaction forceps blades and provides protective coverage of the cleft, traumatized palate, or alveolar bone graft site during the downfracture. The custom maxillary disimpaction splint has been routinely used in our clinic from September 2019 to the present for LeFort osteotomies in patients with a compromised primary palate. No surgical complications related to the maxillary downfracture have been noted during this period of time. We conclude that the routine use of a custom maxillary disimpaction splint can result in improved outcomes and decreased complications of LeFort osteotomy procedures in patients with cleft and traumatized palate.

Do the miniscrews of the prefabricated systems for the “appliance first” protocol of miniscrew-assisted rapid palatal expansion have lengths that meet the palatal thickness of patients?

In the "appliance first" protocol of miniscrew-assisted rapid palatal expansion, the prefabricated shape of the expanders limits the potential locations for miniscrew placement. Considering the influence of palatal thickness on the selection of the optimal length of miniscrews, this study aimed to evaluate the thickness of both bone and mucosa of the palate of patients aged 6-65 years and suggest optimal lengths of miniscrews for this approach. Two hundred and eighty-two cone-beam computed tomography of patients of both sexes were divided into 3 groups according to age. The thicknesses of bone and mucosa were measured in the anterior and posterior regions of the palate. Males showed a greater thickness of palatal bone than females. The thickness of both bone and mucosa was greater in the anterior region of the palate. The young patients showed greater bone thickness than adults and mature adults. The mature adults showed thinner bone thickness in the posterior region of the palate and greater mucosal thickness along the palate than young patients and adults. Development of miniscrews with longer thread lengths is necessary. Miniscrews with a 3-mm thread length would prevent excessive extravasation in the posterior region of the palate. The thickness of both bone and mucosa of the palate is variable and influenced by sex and age. Manufacturing additional miniscrews with different lengths of thread is suggested to achieve bicortical anchorage in patients undergoing the "appliance first" protocol of miniscrew-assisted rapid palatal expansion.

Cone Beam Computed Tomography (CBCT) Evaluation of Alveolar Bone Thickness and Root Angulation in Anterior Maxilla for Planning Immediate Implant Placement.

This retrospective study aimed to measure the labial, palatal, mesial, and distal bone thickness around maxillary central and lateral incisors and canines and height from crest to apex, using cone beam computed tomography (CBCT) images and compare the results based on gender. The second objective of the study was to measure root angulation on CBCT images and its relation with the labial cortical thicknesses. Material and Methods:After the Institutional Review Board (IRB) approval, a total of 140 CBCT volumes were included in this study according to the set criteria. On each scan, right-side maxillary central, lateral incisors, and canine were selected for the measurements. All the measurements were done at three levels at the alveolar crest (L1), mid-root (L2), and apical region (L3) for each tooth. Results:The Student's t-test was performed to compare the result of buccal, palatal, mesial, and distal bone thickness,angulation, and height of all subjects. Buccal alveolar bone thickness was minimum at the mid-root region, and the palatal bone thickness was minimum at the crestal region. The mesial bone thickness was minimum at the mid-root level, and distalbone thickness was minimum at the crest level. The available bone height was maximum at the lateral incisor and equal for the central incisor and canine. The canine was the most angulated tooth. Cone beam computed tomography is a reliable imaging modality to evaluate pre-surgical immediate implant sites and measurealveolar bone thickness. The canine was the most angulated tooth with more buccal alveolar bone thickness.

Osteological correlates of evolutionary transitions in cetacean feeding and related oropharyngeal functions

Teeth are often the first structures that anatomists and paleontologists examine to understand the ecology and morphology of feeding, both because teeth are highly specialized structures that provide precise information, and because they are among the best and most commonly preserved fossils. Unfortunately, many fragmentary fossil and recent specimens lack teeth, and some come from edentulous individuals and taxa, as in mysticete (baleen) whales. In our broad comparative review, we survey non-dental osteological features that, due to size, shape, arrangement, and surface features reflecting muscle attachments, provide useful clues to general or specific aspects of prey capture, intraoral transport, processing, or swallowing. We focus on hyoid, palatal, and pterygoid bones, mandibular symphyses and processes such as the coronoid, and the temporal fossa and zygomatic arch, as well as adjacent cranial bones relating to oral and pharyngeal anatomy. These bones relate to muscles of five general locations especially indicative of feeding: mandibular, hyoid, tongue, pharyngeal, and facial regions. Together these bones and muscles affect feeding and related activities including suckling and breathing. We discuss osteological correlates that provide special relevance to key transitions in cetacean evolutionary history, such as the shift from predominantly terrestrial to aquatic feeding, the shift from typical mammalian mastication to swallowing prey entirely or nearly whole, and the separation of respiratory and digestive passages. We also point to examples of modern specialists in these anatomical optima for different modes of prey capture, intraoral transport, processing, and swallowing. Although we focus on cetaceans, our approach is broadly relevant to all vertebrates, notably other marine tetrapods.

Osteoblastic RAR Inhibition Causes VAD-Like Craniofacial Skeletal Deformity

Retinoid signaling disorders cause craniofacial deformity, among which infants with maternal vitamin A deficiency (VAD) exhibited malformation of the eye, nose, palate, and parietal and jaw bone. Previous research uncovered the pathogenesis of eye defect and cleft palate of VAD in mice, but the studies on craniofacial skeletal deformity met obstacles, and the cell/lineage and underlying mechanism remain unclear. The retinoic acid receptor (RAR) is the key transcription factor in retinoid signaling, but individual knockout cannot simulate pathway inhibition. Here, we conditionally expressed dominant-negative RARα mutation (dnRARα) in osteoblasts to specifically inhibit the transcription activity of RAR in mice, which mimics the craniofacial deformities caused by VAD in clinical cases: hypomineralization of cranial bones, mandibular deformity, and clavicular hypoplasia. Furthermore, we performed 3-dimensional reconstruction based on micro–computed tomography and confirmed the abnormalities in the shape, size, and ossification of craniofacial bones due to osteoblastic RAR inhibition. Histological analysis indicated that inhibition of RAR in osteoblasts impaired both bone formation and bone resorption, which was confirmed by transcriptome sequencing of the calvaria. Furthermore, mechanism investigation showed that inhibition of RAR in osteoblasts directly decreased osteoblast differentiation in a cell-autonomous manner by impairing osteogenic gene transcription and also inhibited osteoclast differentiation via osteoblast–osteoclast crosstalk by impairing Rankl transcription. In summary, osteoblastic RAR activity is critical to craniofacial skeletal development, and its dysfunction leads to skeletal deformities mimicking VAD craniofacial defects, providing a new insight for VAD pathogenesis.

Immediate dentoskeletal and periodontal effects of miniscrew-assisted rapid palatal expansion: Comparison between young vs middle-aged adults

This study aimed to compare the dentoskeletal and periodontal changes after miniscrew-assisted rapid palatal expansion (MARPE) in patients aged 18-29 and 30-45 years. The sample comprised 28 subjects with transverse maxillary discrepancy successfully treated with MARPE. The young adult (YA) group comprised 14 subjects (mean age, 22.8 years; 3 male, 11 female). The middle adult (MA) group comprised 14 subjects (mean age, 36.8 years; 6 male, 8 female). All patients were treated with a 4-miniscrew MARPE expander. The activation protocol was one quarter turn twice a day until the midline diastema opening, followed by one quarter turn a day until overcorrection. Cone-beam computed tomography (CBCT) scans taken before and immediately after the expansion was analyzed using OnDemand3D Dental software. Using CBCT coronal images, transversal dentoskeletal and periodontal variables were measured in the preexpansion and postexpansion. Intergroup comparisons of expansion changes were performed using t and Mann-Whitney tests (P<0.05). Groups were compatible at preexpansion for most CBCT measurements. A success rate of midpalatal suture opening of 100% and 81% was observed for YA and MA groups, respectively. No intergroup differences were found for the maxillary and dental arch widths increases. The buccal tip of anchorage teeth was observed similarly in both groups. The buccal bone thickness of posterior teeth decreased, and the palatal bone thickness increased after expansion with no difference between groups. After MARPE, the MA group showed similar dentoskeletal and periodontal changes compared to the YA group.

Maxillary cortical bone remodeling characteristics in extraction patients: A cone-beam computed tomography study

This study aimed to evaluate labial and palatal cortical bone remodeling (BR) characteristics and related aspects of maxillary incisors after retraction, as these aspects are still controversial among orthodontists. Cortical BR and incisor movement of 44 patients (aged 26.18 ± 4.71 years) who underwent maxillary first premolar extraction and incisor retraction were analyzed using superimposed cone-beam computed tomography images. Labial BR/tooth movement (BT) ratios at the crestal, midroot (S2), and apical (S3) levels were compared using the Friedman test and pairwise comparisons. Multivariate linear regressions were used to explore the relationships between the labial BT ratio and several factors, including age, ANB angle, mandibular plane angle, and incisor movement patterns. According to the type of palatal cortical BR observed, the patients were divided into 3 groups: type I (no BR without root penetration of the original palatal border [RPB]), type II (BR with RPB), and type III (no BR with RPB). Student's t test was used to compare the type II and III groups. The mean labial BT ratios at all levels were<1.00 (0.68-0.89). This value at the S3 level was significantly smaller than that at the crestal and S2 levels (P<0.01). Multivariate linear regression indicated that the tooth movement pattern negatively correlates with the BT ratio at S2 and S3 levels (P<0.01). Type I was noted in 40.9% of the patients, and similar proportions exhibited type II (29.5%, 25.0%) or type III remodeling (29.5%, 34.1%). The retraction distance of the incisors in type III patients was significantly larger than in type II patients (P<0.05). The amount of cortical BR secondary to maxillary incisor retraction is less than the tooth movement. Bodily retraction may lead to lower labial BT ratios at the S3 and S2 levels. Roots penetrating the original border of the cortical plate are necessary for palatal cortical BR initiation.

Bone quality in relation to skeletal maturation in palatal miniscrews insertion sites

This study aimed to investigate the relationship between bone density and quantity at the insertion sites of palatal miniscrews and skeletal maturation-evaluated with the middle phalanx maturation method-in growing patients. Sixty patients were analyzed as having a staged third finger middle phalanx radiograph and a cone-beam computed tomography of the maxilla. On the cone-beam computed tomography, a grid was designed to parallel the midpalatal suture (MPS) and posterior to the nasopalatine foramen, both on the palatal and lower nasal cortical bones. Bone density and thickness were measured at the intersections, and medullary bone density was also calculated. Of patients in MPS stages 1-3, 67.6% showed a mean palatal cortical thickness of<1 mm, whereas in 78.3% of the patients in stages 4 and 5, it was>1 mm. The nasal cortical thickness showed a similar trend (MPS stages 1-3: 62.16%<1 mm; MPS stages 4 and 5: 65.2%>1 mm). There was a significant difference in the density of the palatal cortical bone between MPS stages 1-3 (1272.05 ± 191.13) and stages 4 and 5 (1572.33 ± 274.89) and in nasal cortical density between MPS stages 1-3 (1428.09 ± 198.97) and stages 4 and 5 (1597.97 ± 267.75) (P<0.001). This study revealed a correlation between skeletal maturity and maxillary bone quality. MPS stages 1-3 have lower palatal cortical bone density and thickness but high nasal cortical bone density values. MPS stage 4 and, even more, stage 5 show increasing palatal cortical bone thickness and palatal and nasal cortical bone density values.

Nasal capsule ossification: A histological study using human foetuses to find an association between the foetus and adult morphologies of the nasal wall.

Recent molecular biology studies have revealed the process of nasal capsule determination. We aimed to create a fate map showing the association between the adult and embryonic components of the nasal wall and nasal capsule derivatives. We examined paraffin-embedded histological sections between 15 mid-term (9-16 weeks) and 12 near-term (27-40 weeks) foetuses. Until 15 weeks, membranous ossification occurred 'along' the capsular cartilage, contributing to the formation of the vomer, maxilla and bony nasal septum as well as the nasal, frontal and lacrimal bones. After 15 weeks, a wide lateral part of the capsule became thin and fragmented, and degenerative cartilage was observed near the lacrimal bone, in the three conchae, and at the inferolateral end of the capsule sandwiched between the maxilla and palatine bone. The disappearing cartilages appeared to be replaced by nearby membranous bones. This type of membranous ossification did not appear to use the capsular cartilage as a 'mould', although the perichondrium may have a role in inducing ossification. Calcified cartilage indicated endochondral ossification in the inferior concha until 15 weeks and, later, at the bases of three conchae and around the future sphenoid sinus (i.e. the concha sphenoidalis). The capsular cartilage extended antero-superiorly over the frontal bone and inserted into the nasal bone. At 40 weeks, the capsular cartilage remained in the cribriform plate and at the inferolateral end along the palatine bone. Consequently, less guidance from the nasal capsule seemed to provide great individual variation in the shape of the wide anterolateral wall of the nasal cavity.

Evaluation of palate-related factors of the effectiveness of microimplant-assisted rapid palatal expansion in late adolescents and adults.

This study investigated the factors of the effectiveness of microimplant-assisted rapid palatal expansion (MARPE) in late adolescents and adults, such as age, midpalatal suture maturation (MPSM) stage, palate length (PL), palatal index (PI), and midpalatal bone thickness (MBT), and at each microimplant position, the palate bone thickness (PBT), the nasal cortical bone thickness (CoTN), the cancellous bone thickness (CaT), and the palate cortical bone thickness (CoTP) were evaluated. Cone-beam computed tomography (CBCT) images of 50 patients (mean, 23.30 ± 7.03years; range, 16-51years) treated with MARPE were evaluated. Maxillary expansion ratio (MER) was used to assess the MARPE effectiveness and grouped patients into low and high MER groups according to the mean of MER. MER was the ratio of maxillary expansion width to MARPE screw expansion measured in CBCT images. Thet-test was used to analyze the differences between the low and high MER groups. The Pearson correlation test was performed to investigate the correlation between MER and age, MPSM stage, PL, PI, MBT, PBT, CoTN, CaT, and CoTP. Age, MPSM stage, and MBT in regions 18mm and 21mm behind the incisor foramen correlated negatively with MER ([Formula: see text], - 0.390, - 0.386, and - 0.335, respectively, all [Formula: see text]), whereas PBT and CoTN of anterior microimplant positions correlated positively with MER ([Formula: see text] and 0.418, respectively, all [Formula: see text]). No correlation was observed between other variables and MER. MARPE effectiveness decreased as age and midpalatal suture maturation stage increased, respectively. Thinner midpalatal suture bone in regions 18mm and 21mm behind the incisor foramen, thicker palate bone, and nasal cortical bone of anterior microimplant positions were related to more effective MARPE. In patients with older chronological age and later MPSM stages, MARPE effectiveness might be unsatisfactory. Clinicians should carefully evaluate the palate bone thickness before MARPE treatment.

Association of Computed Tomography Values of the Tooth Root and Alveolar Bone with Orthodontic Root Resorption

This study aimed to evaluate the effect of CT values of the tooth root and bone on root resorption using data obtained before and after orthodontic treatment. Forty-one patients with jaw deformities were divided into those with and without root resorption （n = 18 and 23, respectively）. The distance from the anatomical root apex to the edge of the incisive canal was measured using axial CT sections before active treatment. The distance from the anatomical root apex to the labial and palatal cortical bone and the CT values of the root and alveolar bone were measured and compared using sagittal CT sections. The tooth axis and vertical and lateral movements of the maxillary right central incisor were examined using lateral cephalograms before and after treatment. Root resorption group showed significantly higher CT values of alveolar bone than the control group and different axial movement of the root apex and distance between the labial cortical bone and root apex on lateral cephalograms. The risk of root resorption increased with an increase in the CT values of the alveolar bone surrounding the maxillary central incisor. The horizontal movement of the root apex was associated with the distance between the labial cortical bone and root apex, and root resorption during maxillary central incisor movement.

Topographic and anatomical substantiation of the use of vascularized flaps for plastic reconstruction of soft tissues of the alveolar ridge

Promising scientific research in modern dentistry and maxillofacial surgery is focused on solving the issues of long-term and stable results of implant treatment in the rehabilitation of patients with partial or complete absence of teeth in conditions of deficiency of the soft tissue component of the alveolar ridge. Clinicians have proposed a variety of plastic surgery techniques, in which soft tissue defects are simultaneously replaced with a vascularized flap, a revascularized autograft, or by stage-by-stage replacement of a defect with a pedunculated flap, followed by its cut-ting off and modeling, taking into account the individual characteristics of the formed area. The long-term clinical success of dental implantation is largely determined by the functional state and reactive properties of the soft tissues surrounding the implant, which play an important role not only in achieving a highly aesthetic result, but also in preventing complications of implant treatment. The use of an operative multi-stage method for reconstructing the soft tissue component of the alveolar ridge with a mu-coperiosteal vascularized flap from the bone palate, developed on animal biological dummies (pigs), allows you to pre-plan the volume of surgical intervention, as well as the shape of the donor and recipient zones. Topographic and anatomical substantia-tion of the optimal modeling of the mucoperiosteal flap from the bone palate will al-low avoiding excessive donor tissue sampling, minimizing the invasiveness and trauma of surgical intervention, forming a soft tissue buffer zone of the required vol-ume to prevent bone resorption in the peri-implant area, increase the service life of dental implants, increase the reliability of prosthetic designs and long-term operation.