Anatomy of the greater palatine foramen and canal and their clinical significance in relation to the greater palatine artery: a systematic review and meta-analysis.

PURPOSE: Accurate knowledge of greater palatine foramen (GPF) and greater palatine canal (GPC) anatomy is necessary to avoid injury to the greater palatine artery (GPA) when performing a variety of anesthesiologic, dental or surgical procedures. The aim of this paper was to perform a systematic review and meta-analysis of literature on the anatomy and localization of bony structures associated with the GPA, namely the GPF and GPC. METHODS: A systematic literature search was performed using PubMed, Embase, ScienceDirect, and Web of Science databases. Seventy-five studies were included in the meta-analysis (n = 22,202 subjects). RESULTS: The meta-analysis showed that the GPF is positioned 17.21 mm (95% CI = 16.34-18.09 mm) from the posterior nasal spine, 2.56 mm (95% CI = 1.90-3.22 mm) from the posterior border of the hard palate, 46.24 mm (95% CI = 44.30-48.18 mm) from the anterior nasal spine, 15.22 mm (95% CI = 15.00-15.43 mm) from the midline maxillary suture, 37.32 mm (95% CI = 36.19-38.45 mm) from the incisive foramen, and opposite the third maxillary molar (M3) in 64.9% (58.7-70.7%) of the total population. CONCLUSION: An up-to-date, comprehensive analysis of GPF and GPC clinical anatomy is presented. The results from this evidence-based anatomical study provides a unified set of data to aid clinicians in their practice.

Morphology of the greater palatine foramen: a clinical point of view.

PURPOSE: Anatomical characteristics of the greater palatine foramen (GPF) are essential during the greater palatine nerve block application to anesthetize maxillary teeth, gums, midface, and nasal cavities. The position of GPF is usually described in relation to adjacent anatomical structures. This investigation aims to examine the morphometric relationships of GPF and closely determine its position. METHODS: The study included 87 skulls (174 foramina). They were photographed in a horizontal position with bases facing up. The digital data were processed in the ImageJ 1.53n software. RESULTS: The average distance of the GPF from the median palatine suture was 15.94 mm. In relation to the posterior border of the bony palate, the distance was 2.05 mm. Statistical significance was found in comparing the angle between the GPF, incisive fossa, and the median palatine suture between the sides of the skulls (p = 0.02). Comparing tested parameters between males and females showed significant differences in GPF-MPS (p = 0.003) and GPF-pb (p = 0.012), with lower values in females. The most significant percentage of skulls (77.01%) had the GPF located at the level of the third molar. The most significant number of bony palates had one lesser opening (60.91%) on the left side. CONCLUSION: GPF is located at the level of the maxillary third molar in most of the examined palates. Knowledge of the anatomical position of the greater palatine foramen and its variations is the basis for successfully implementing anesthesia and various surgical interventions.

Changing the topographical anatomy among the maxilla, palatine bone, and greater palatine nerve: a histological study using human fetuses.

PURPOSE: The palatine bone (PAL) rides over the maxilla (MX) without an end-to-end suture in the bony palate of fetuses. However, changes in the topographical relationship among bones was unknown at and along the pterygopalatomaxillary suture, including the palatine canals. METHODS: Using sagittal, frontal, and horizontal histological sections of the head from 15 midterm fetuses to 12 near-term fetuses, we depicted the changes in the topographical anatomy of the MX, PAL, and greater palatine nerve (GPN). RESULTS: In the bony greater palatine canal of these fetuses, the medial and posterior walls facing the GPN were consistently made up of the PAL. At midterm, the entire course of the GPN was embedded in the PAL (six fetuses), or the MX contributed to the lateral wall of the nerve canal (nine). At near-term, the anterior and lateral walls showed individual variations: an MX in the anterior and lateral walls (three fetuses), an anterior MX and a lateral PAL (five), an anterior PAL and a lateral MX (two), and a PAL surrounding the GPN (four). CONCLUSION: These increasing variations suggested that the pterygopalatomaxillary suture was actually growing and that the PAL transiently expanded anteriorly and/or laterally to push the MX in fetuses. The "usual" morphology in which the GPN is sandwiched by the MX and PAL is likely established after birth, possibly during adolescence. The driving force of this change may not be produced by the masticatory apparatus. Rather, it might be triggered by the growing maxillary sinus.

Morphometric analysis of the palatine triangle in adult human skulls: a potential aid for anthropologists and intraoral bone grafts.

Morphometrics of the hard palate is an important aspect of forensic anthropology and odontology. Palatine triangle is a triangular area in the hard palate formed by the palatine processes of the maxillae, which can aid intraoral bone grafts. We present the osteological measurements of the palatine triangle (maxillary palate) based on sex, compare it with other hard palate parameters, and establish the correlation between them. Seventy-seven male skulls and 36 female skulls were examined. Various morphometric measurements of the hard palate and palatine triangle were performed meticulously. Mean and standard deviation of each parameter were computed for groups using SPSS 16.0. Relationships between all parameters were analyzed using Pearson's rank correlation test. The mean palatine length was 38.84 ± 3.75 mm in males and 37.22 ± 4.12 mm in females; the mean palatine breadth was 31.36 ± 2.61 mm in males and 29.78 ± 3.07 mm in females. The mean area of the palatine triangle was 600.88 ± 80.16 mm2 in male skulls and 547.96 ± 94.28 mm2 in the female skulls. Statistically significant difference in various measurements of the palatine triangle and hard palate between the male and female skulls was noted. Leptostaphyline (narrow palate) was the most prominent type of palate. The area of the palatine triangle showed a strong positive correlation between the total length and breadth of the palate for both male and female skulls. A strong positive correlation was also observed between the palate length and the palatine triangle length. Palatine index and palate breadth had a statistically significant moderate linear relationship. The maxillary palate length, breadth, and area of the palatine triangle were higher in males when compared to females in South Indian origin skulls. Most of the skulls had a narrow palate. The results of this metric analysis of the palatine triangle may lead to a new concept of anatomical research into studying the hard palate, which can be used for sexual dimorphism.

Radiological evaluation of the bone and soft tissue thicknesses of the palate for using a miniscrew-supported maxillary skeletal expander.

PURPOSE: The purpose of this study was to determine the palatal bone and soft tissue thicknesses using a miniscrew-supported maxillary skeletal expander (MSE) in Class III malocclusion. METHODS: The thicknesses of the palatal bone and soft tissue were measured in cone-beam computed tomography images obtained from 58 patients. All 20 points were crossing points between five levels, which were defined at 3 mm intervals relative to the line connecting the central fossae of the first molar (Level 0), and 2 mm and 4 mm lateral to the anteroposterior reference line (AP line). RESULTS: The palatal bone was significantly thicker in males than females in the anterior palate up to Level 0, while there was no significant sex-related difference in the posterior palate. There was a tendency for the thickness to decrease in the posterior direction, except in females at 2 mm lateral to the AP line. The palatal soft tissue was significantly thicker in males than females in all positions. At 2 mm lateral to the AP line, the palatal soft tissue thickness decreased in the posterior direction. A 4 mm lateral to the AP line, it initially decreased in the posterior direction, and then increasing again at Level - 6 (6 mm posterior of Level 0). As the lateral distance from the AP line increased, the palatal bone thickness decreased while the palatal soft tissue thickness increased. CONCLUSIONS: These findings provide quantitative data on the palatal bone and soft tissue thicknesses for the miniscrew-supported MSE in the posterior palate.

Development of a novel histological and histomorphometric evaluation protocol for a standardized description of the mid-palatal suture - An ex vivo study.

The hard palate and mid-palatal suture are highly important for orthodontic treatment. In cases of transverse maxillary deficiency, palatal expansion is the treatment of choice. As nowadays a growing number of adult patients receive orthodontic treatment, an understanding of suture development throughout life is important to derive tailored orthodontic treatment techniques for each age group. Histological, histochemical and immunohistochemical stains (haematoxylin & eosin, Azan, Movat pentachrome, Masson-Goldner trichrome, Sirius Red, CD 31, osteopontin and TRAP) and histomorphometric analyses were re-established to detect the structural conditions of the mid-palatal suture in human cadavers of three different age groups (20-39, 40-59 and 60-80 years). The mid-palatal suture of the selected age groups (total of n = 12; n = 4 in every group m = f) exhibited marked differences in sutural morphology and metabolism. A wide, interdigitated and well-vascularized suture was observed in younger specimens compared with straighter and smaller sutures with fewer vessels and lower bone density in the 60-80 year group. The fibre composition within the sutural gap differed between the three age groups. Delicate fibres were found in the 20-39 year group, and a tightly interwoven 3D fibre-network was observed in the 40-59 year group. Atrophy primarily characterized the fibres in the 60-80 year group. This evidence demonstrates differences between the evaluated groups. These results suggest that the staining methods used are suitable for the description and evaluation of the morphology and metabolism of mid-palatal sutures. Further investigation is necessary to provide an in-depth description of sutural maturation over a lifetime.

Morphological Evaluation of the Nasopalatine Canal in Patients With Different Facial Profiles and Ages.

PURPOSE: To evaluate the influence of facial profile and age on the morphology of the nasopalatine canal. MATERIALS AND METHODS: One hundred thirty-two cone-beam computed tomograms were classified according to facial profile-mesofacial, brachyfacial, and dolichofacial-and divided into the following age groups: 21 to 30, 31 to 40, 41 to 50, and 51 to 60 years. Measurements were obtained for openings of the incisive and nasopalatine foramina, alveolar bone thickness, and the full length, most constricted region, and volume of the nasopalatine canal. Intra- and inter-examiner agreements were calculated using the intraclass correlation coefficient. After exploratory and descriptive analysis, data were subjected to 2-way analysis of variance and Tukey test for comparisons between facial profiles and age groups. The significance level was 5% (α = 0.05). RESULTS: Intra- and inter-examiner reproducibilities were excellent for all measurements. Patients older than 50 years presented a significantly larger nasopalatine canal than patients 21 to 30 years old for all facial profiles (P ≤ .05). Linear measurements obtained from the nasopalatine canal showed no significant difference between facial profiles and age groups (P > .05). CONCLUSIONS: The nasopalatine canal was not influenced by facial profile but did exhibit an increased volume with aging, particularly after 50 years of age.

Cone-Beam Computed Tomography Study on Morphologic Characteristics of the Posterior Region in Hard Palate.

BACKGROUND: The goal of this study is to evaluate the morphologic characteristics of the posterior palatine region among the Chinese population, more specifically, the greater palatine grooves, crests, bridges, and torus palatinus structures and make comparisons between different ethnic groups and minorities. METHODS: A total of 323 cone-beam computed tomography (CBCT) scans were collected for analysis on the presence of grooves, crests, bridges, or torus palatinus (TP). Data were collected through recognizing the grooves, crests, bridges, and TPs and calculating the number of those anatomy structures. The statistics index, including average, standard deviation, were adopted to describe the subjects and Wilcoxon test, Mann-Whitney test, and Chi-squared test were all carried out by SPSS. RESULTS: Three different morphologic manifestations of the greater palatine groove (GPG) found in the upper 1st and 2nd molar regions are as follows: no groove, 1 groove, and 2 grooves. The number of crests ranged from 0 to 3. And the incidence of torus palatines was 29%. Moreover, a positive correlation was found between the presence of crests/GPGs and age in the 2nd molar region. CONCLUSION: The results in this study reveal that GPGs in the upper 1st and 2nd molar regions have 3 different morphologic manifestations among Chinese people and the number of crests can vary from 0 to 3 crests. Although the proportion of GPG or crest and the incidence of TP are different from the proportions of other studies, this may be due to the fact that different ethnic groups and sample sizes were used in the course of this study. Information about the anatomy structures of the posterior region in hard palate directly contributed to a decrease in potential complications during palatal implant surgery and periodontal surgery.

Tongue pressure distribution of individual normal occlusions and exploration of related factors.

BACKGROUND: Tongue plays an important part in oral and maxillofacial system. Measurement of tongue pressure helps to evaluate the performance of tongue movement. OBJECTIVES: To establish a system for measuring tongue pressure against hard palate and to preliminarily explore pressure distribution of individual normal occlusions and the relationship with dental arch form. METHODS: A total of 19 volunteers of individual normal occlusions out of 189 dental students met inclusion criteria (nine males, ten females, aged 25.53 ± 0.96 years). A force-sensing resistor device was used to measure tongue pressure at rest and functional state (swallowing). We observed tongue pressure of four channel (anterior, posterior and lateral sides of hard palate) in sitting, supine position and swallowing. We analysed pressure differences according to gender and explored correlation relationship between tongue pressure and dental arch width and length using 3D digital maxillary image. RESULTS: In rest, tongue pressure against hard palate increased from front to back in both sitting and supine position, without gender differences. When swallowing saliva, the pressure at lateral sides of females was found significantly higher than that of males. Bivariate correlation analysis revealed duration of swallowing was positively correlated with BMI and weight at posterior region and positively correlated with palatal length at anterior palate. The greater the dental arch width, the smaller the pressure of swallowing in the anterior and lateral region. CONCLUSION: In rest, there was consistent pressure of tongue against hard palate. The pressure increased significantly during swallowing, especially in females. Tongue pressure was related to dental arch length, width, BMI and weight.

Morphometric evaluation and clinical implications of the greater palatine foramen, greater palatine canal and pterygopalatine fossa on CBCT images and review of literature.

INTRODUCTION: The pterygopalatine fossa (PPF) infiltration is performed to reduce blood flow during endoscopic sinus surgery and septorhinoplasty, as well as to control posterior epistaxis and provide regional anesthesia in dental procedures. PPF infiltration performed with consideration of the morphometrics of greater palatine foramen (GPF), greater palatine canal (GPC) and PPF would increase the success of the procedure and reduce the risk of complications. The aim of this study is to investigate the GPF, GPC, lesser palatine foramen (LPF), lesser palatine canal (LPC) and PPF morphology via the images obtained by CBCT, to provide information for interventional procedures. MATERIALS AND METHODS: GPF, GPC, LPF, LPC and PPF were morphometrically evaluated retrospectively in CBCT images of 75 female and 75 male cases by Planmeca Romexis program. The 19 parameters were measured on these images. RESULTS: These parameters were evaluated statistically. The comparison of these parameters by genders revealed significant differences in distances between GPC-PC, PC-IOF, LPC-GPF, GPF-MS in the coronal and transverse planes, the distance between GPF and the occlusal plane of the teeth, GPF-PNS, GPF-IF and TD-GPF, and in the area of GPF. The number of LPF was found ranging from 1 to 5. CONCLUSION: Our results may help to insert to needle properly for application of maxillary nerve block with a high success rate and minimal complication. We recommend that the needle should be inserted 14-15 mm lateral to the midsagittal plane, 19-20 mm over the occlusal plane of the teeth and on the same line with the third molar teeth. For PPF infiltration through the GPF, the needle should be pushed forward 28 mm upward at 66° angle on the transverse plane and 14°-15° angle on the vertical plane.

The Association between Morphological Characteristics of Palatal Rugae and Sagittal Skeletal Patterns.

INTRODUCTION: To find the association between the morphological characteristics of palatal rugae and sagittal skeletal patterns. METHODS: The retrospective charts review was conducted at the Aga Khan University Hospital from April to June 2016, and comprised data obtained from the pretreatment dental cast of orthodontic patients visiting the dental clinics over 5 years from 2011 to 2015. The sample was divided equally in three malocclusion groups based on sagittal skeletal relationship Class I, Class II and Class III. The number of palatal rugae was recorded for both right and left sides. Morphological features of the three anterior most primary rugae were recorded for the length, pattern and orientation bilaterally. SPSS 20 was used to compare the number and lengths as well as the pattern and orientation of palatal rugae among the groups. RESULTS: Of the 165 subjects, there were 55(33.3%) in each of the three groups. Significant differences were recorded in rugae lengths among the groups at ruga 1 on both sides and rugae 2 and 3 on the left side (p<0.05 each). There were significant differences in the palatal rugae patterns among the groups (p<0.05) except at rugae 2 and 3 on the left side (p>0.05). Orientation showed significant differences at ruga 2 on the right side (p=0.02). CONCLUSIONS: No specific pattern was associated with any skeletal pattern. Further studies are required to evaluate three-dimensional characteristics of rugae to assess the association between palatal rugae and sagittal skeletal patterns.

Application of 3D models of palatal rugae to personal identification: hints at identification from 3D-3D superimposition techniques.

Palatal rugae are known in literature as individualizing anatomical structures with a strong potential for personal identification. However, a 3D assessment of their uniqueness has not yet been performed. The present study aims at verifying the uniqueness of 3D models of the palate. Twenty-six subjects were recruited among the orthodontic patients of a private dental office; from every patient, at least two dental casts were taken in different time periods, for a total of 62 casts. Dental casts were digitized by a 3D laser scanner (iSeries, Dental Wings©, Montreal, Canada). The palatal area was identified, and a series of 250 superimpositions was then performed automatically through VAM©software in order to reach the minimum point-to point distance between two models. In 36 matches the models belonged to the same individual, whereas in 214 mismatches they came from different subjects. The RMS (root mean square) of point-to-point distances was then calculated by 3D software. Possible statistically significant differences were assessed through Mann-Whitney test (p < 0.05). Results showed a statistically significant difference in RMS mean point-to-point distance between matches (mean 0.26 mm; SD 0.12) and mismatches (mean 1.30; SD 0.44) (p < 0.0001).All matches reached an RMS value below 0.50 mm. This study first provided an assessment of uniqueness of palatal rugae, based on their anatomical 3D conformations, with consequent applications to personal identification.

3D software scanning, processing and archiving palatal rugae: "identity base" technology.

The palatal rugae, which are anatomically described as folds or wrinkles of the palate, are located on the anterior third of the palate on each side of the palatal raphe and behind the incisive papilla. The use of palatal rugae for personal identification was suggested several years ago, and attracted interest from different researchers which created different classifications, still used in scientific literature. The "identity base" (IB) system has as its object a complex information system and a personal identification protocol by means of three-dimensional palatal scans in digital format. The usefulness of this system is based on the management needs of big data. For example, in the field of forensic odontology, IB can be useful in the identification of a living or cadaver subject; and can estimate the age of a human subject. Moreover, IB stores its associated biometric data. The IB system demonstrated to overcome the issues shown by other similar systems of digital image storage. Furthermore, its high accuracy in the identification process makes IB a reliable tool for institutions in the management of immigrants, as well as in the archiving of people under restrictive measures. Finally, IB is also a system for sharing and processing clinical images, useful in dental prosthetics to reduce the number of steps from the first visit to dental prosthesis. The next generation of big-data archiving will speak the same language as IB: the route has been already set out.

Morphometric Analysis of the Orbital Process of the Palatine Bone and its Relationship to Endoscopic Orbital Apex Surgery.

BACKGROUND: Endoscopic approaches to the orbit improve the ability to directly access apical lesions while minimizing manipulation of normal structures. Inferomedial orbital access is limited by the orbital process of the palatine bone (OPPB) which prevents dissection and retraction in the inferolateral vector. OBJECTIVE: The objective of this study was to examine the morphometric characteristics of the OPPB and quantify the benefit of complete resection to surgical access. METHODS: Morphometric osteologic measurements of the OPPB were performed in 59 human skulls. A radius subtended by the OPPB was calculated to generate a hemispheric dissection corridor achievable by complete resection of the OPPB. Cadaveric and live surgical dissections were then performed on 15 orbits to develop discreet endoscopic surgical landmarks which could be used to both identify the OPPB and verify complete resection. RESULTS: The mean(± SD) radius of the OPPB was 0.47 ± 0.28 cm. Complete OPPB resection provided an additional 0.36 ± 0.42 cm of surgical exposure within the inferomedial apex. Relative to the Caucasian (n = 27) skulls, the radii in the Asian (n = 27) and African (n = 5) skulls were significantly smaller (p < 0.001 and p = 0.02, respectively). CONCLUSION: The OPPB significantly limits surgical access to the inferomedial orbital apex during endoscopic approaches. Complete surgical resection of the OPPB improves surgical exposure facilitating retraction of the inferior rectus muscle and circumferential dissection of lesions within this space. Knowledge of the morphology and clinical relevance of this structure provides an opportunity to improve surgical exposure for relevant pathologic assessment and optimize endoscopic surgical outcomes.

Effect of tongue-palate contact mode on food transport during mastication.

The physiological mechanisms underlying Stage II transport (STII), during which comminuted solid food is transported from the oral cavity into the meso-pharynx for aggregation into a pre-swallow bolus, have yet to be clarified. The purpose of the present study was to investigate relationships between tongue-palate contact during mastication and incidence of STII by synchronised analysis of tongue pressure production on a hard palate and video-endoscopic (VE) images during mastication. Tongue pressure at 5 measuring points with an ultra-thin sensor sheet attached to the hard palate and trans-nasal VE images while masticating corned beef was recorded for 12 healthy subjects. All recordings were divided into 2 groups: mastication with STII and without STII. Tongue pressure duration was longer at the anterior-median part in the group with STII than in the group without STII. Integrated values of tongue pressure were greater at the anterior-median parts and posterior circumferential part in the group with STII. Integrated values of tongue pressure per second were greater in late-stage mastication than in early-stage mastication in the group with STII. These results suggest that the tongue-palate contacting at the anterior-median and post-circumferential parts of the hard palate is related with the incidence of STII.

Anatomical study of the palatine aponeurosis: application to posterior palatal seal of the complete maxillary denture.

The palatine aponeurosis is a thin, fibrous lamella comprising the extended tendons of the tensor veli palatini muscles, attached to the posterior border and inferior surface of the palatine bone. In dentistry, the relationship between the "vibrating line" and the border of the hard and soft palate has long been discussed. However, to our knowledge, there has been no discussion of the relationship between the palatine aponeurosis and the vibrating line(s). Twenty sides from ten fresh frozen White cadaveric heads (seven males and three females) whose mean age at death was 79 years) were used in this study. The thickness of the mucosa including the submucosal tissue was measured. The maximum length of the palatine aponeurosis on each side and the distance from the posterior nasal spine to the posterior border of the palatine aponeurosis in the midline were also measured. The relationship between the marked borderlines and the posterior border of the palatine bone was observed. The thickness of the mucosa and submucosal tissue on the posterior nasal spine and the maximum length of the palatine aponeurosis were 3.4 mm, and 12.2 mm on right side and 12.8 mm on left, respectively. The length of the palatine aponeurosis in the midline was 4.9 mm. In all specimens, the borderline between the compressible and incompressible parts corresponded to the posterior border of the palatine bone.

Registration of serial maxillary models via the weighted rugae superimposition method.

OBJECTIVES: We introduce a weighted method for superimposition of serial digital maxillary models based on the variable stability of rugae points. SETTING AND SAMPLE POPULATION: Plaster maxillary models of 24 randomly selected 12-year-olds as well as their models at the age of 14 were obtained and scanned using a benchtop structured-light 3D scanner. METHODS: The models were registered twice, once via the unweighted and again via the proposed weighted rugae superimposition method based on 12 rugae landmarks. For each superimposition, distances between the corresponding rugae points were measured and compared with reported displacements of rugae points in literature. RESULTS: The unweighted superimposition produced no meaningful differences in terms of total displacements of registration landmarks, whereas the weighted method recognized the medial points of the third ruga as the most stable landmarks. Results of the weighted method also demonstrated statistically significant smaller changes for medial rugae points in almost every dimension compared to the lateral rugae points. These results comply with the growth patterns of maxilla and rugae point displacements reported in similar studies. CONCLUSION: Considering the variable stability of rugae points during growth, the weighted rugae superimposition method results in more promising registrations on serial models. This method prioritizes registration landmarks based on clinical criteria of choice and is suitable for analysis of other structures such as tooth movements.

Simulating alveolar trills using a two-mass model of the tongue tip.

This paper investigates the possibility of reproducing the self-sustained oscillation of the tongue tip in alveolar trills. The interest is to study the articulatory and phonatory configurations that are required to produce alveolar trills. Using a realistic geometry of the vocal tract, derived from cineMRI data of a real speaker, the paper studies the mechanical behavior of a lumped two-mass model of the tongue tip. Then, the paper proposes a solution to simulate the incomplete occlusion of the vocal tract during linguopalatal contacts by adding a lateral acoustic waveguide. Finally, the simulation framework is used to study the impact of a set of parameters on the characteristic features of the produced alveolar trills. It shows that the production of trills is favored when the distance between the equilibrium position of the tongue tip and the hard palate in the alveolar zone is less than 1 mm, but without linguopalatal contact, and when the glottis is fully adducted.

Evaluation of Palatal Bone Thickness for Insertion of Orthodontic Mini-Implants in Adults and Adolescents.

OBJECTIVE: The aim of this study was to measure palatal bone thickness and select relatively safe regions for mini-implant insertion, and to determine the effect of age and sex on palatal bone thickness and whether there is any difference between right and left sides. MATERIALS AND METHODS: Cone beam computed tomographic (CBCT) evaluation was used on 107 healthy orthodontic patients, including 51 adolescents (12.90 ±â€Š1.71 years) and 56 adults (26.09 ±â€Š4.35 years), who were selected from the Zhongshan Hospital, Fudan University (Shanghai, China). Seventy-two sites of bone thickness were measured in the palate. Intragroup, intergroup, and sex differences were analyzed by repeated measures analysis of variance. RESULTS: Palatal bone thickness exhibited significant differences in 3 anteroposterior areas of the 2 groups. From anterior to posterior region, palatal bone thickness gradually decreased. Meanwhile, on the sagittal plane, palatal bone thickness decreased gradually from reference line 0 to 9 mm among adults, and from reference line 0 to 12 mm among adolescents posterior to the level of the posterior rim of the incisive foramen. However, on the coronal plane, no significant differences were found in the palatal bone thickness among reference lines 2, 4, 6, and 8 mm lateral to the midpalatal suture. Nor were there differences between right and left sides, between adults and adolescents or between males and females. CONCLUSIONS: In terms of bone thickness, the anterior region is relatively safe for orthodontic mini-implant insertion. However, since subjects vary greatly, CBCT scans are needed before undertaking mini-implant insertion.

Intracranial Anatomic Landmarks for Endoscopic Endonasal Transcribriform Approach to Anterior Skull Base.

OBJECTIVES: To help surgeons locating anatomic landmarks when performing endoscopic endonasal transcribriform approach to anterior skull base. METHODS: High-resolution axial computed tomography (CT) images at thickness of 0.6 mm, and reconstructed 0.41-mm thick gapless sagittal and coronal CT images were taken from 123 subjects. Using mimics software, first located elementary points and line: nasal spine, midpoint of posterior hard palate and the line between them; then located measured points right/left posterior and anterior points; measured distances between measured points and from measured points to nasal spine and angles between lines connecting measured points to nasal spine and the basic line. RESULTS: The distances from nasal spine to right/left posterior and anterior points of anterior skull base are 68.67 ± 6.04 and 61.71 ± 5.09 mm, corresponding angles are 45.89 ± 4.20° and 72.07 ± 4.06°, respectively. The width and length of defect of anterior skull base are 24.45 ± 2.62 and 31.03 ± 4.96 mm; its area ranges from 373.75 ± 94.08 to 800.91 ± 195.07 mm. CONCLUSIONS: The study provides information about anterior skull base anatomic landmarks, which can help surgeons to locate them and avoid relative complications during endoscopic endonasal transcribriform approach to anterior skull base. The measurements can be used as surgical indicators to investigate the landmarks.