Alveolar bone morphology in patients with palatally-displaced maxillary lateral incisors before and after orthodontic treatment: A cone-beam computed tomography study.

INTRODUCTION: Palatal displacement of maxillary anterior teeth is common in clinical practice. Previous studies have reported that the labial bone around palatally-displaced incisors is thinner than that around normally-placed teeth. Therefore, it is necessary to elucidate alveolar bone changes after alignment to guide orthodontic treatment. In this study, we investigated the alveolar bone changes around palatally-displaced maxillary lateral incisors before and after treatment, and the effects of extraction and age using cone-beam computed tomography. METHODS: In this retrospective study, 55 patients with unilateral palatally-displaced maxillary lateral incisors were included. Three-dimensional alveolar bone changes were measured at three levels (25%, 50% and 75% of the root length) using cone-beam computed tomography. Group comparisons were made between displaced and control teeth, extraction and non-extraction groups, and adult and minor groups. RESULTS: After orthodontic treatment, labiopalatal and palatal alveolar bone widths decreased at all measured levels. Labial alveolar bone width increased significantly at P25, but decreased at P75. Concavity decreased, while tooth-axis angle, tooth length, B-CEJ and P-CEJ increased. Changes in LB and LP at P75, B-CEJ and P-CEJ were statistically significant. After treatment, the tooth-axis angle on the PD side increased by 9.46°. The change in tooth-axis angle on the PD side was significantly smaller, and LB and LP decreased more at P75, in the extraction group. CONCLUSIONS: Compared to the control teeth, alveolar bone thickness and height for the displaced teeth decreased more significantly after treatment. Tooth extraction and age also influenced alveolar bone changes.

Three-dimensional analysis of the alveolar ridge profiles of maxillary central incisors in children for autotransplantation.

BACKGROUND: Sufficient alveolar housing is fundamental to ensure the favorable prognosis of autotransplanted teeth. However, little is known about the alveolar ridge profiles of the anterior maxilla in children. Therefore, this study aimed to investigate the alveolar ridge profiles of the anterior maxilla in growing children. METHODS: A total of 169 Korean children aged 10-13 years old were included in this retrospective study. Demographic data and cone-beam computed tomography scans of 244 maxillary central incisors were collected. For each tooth, the alveolar ridge thickness was determined at 1-, 3-, and 5-mm levels below the cemento-enamel junction. The alveolar process height and labial concavity were also evaluated. Statistical analyses were performed to evaluate differences according to age and sex. RESULTS: The alveolar ridge thickness did not differ according to age. The alveolar ridge thickness in males was significantly greater than that in females among those aged 10 and 11 years. The average alveolar process height was 17.43 ± 2.22 mm. The alveolar process height hardly changed with age from 10-13 years, whereas the alveolar process height of males was significantly greater compared with that of females among those aged 10 years. The labial concavity was approximately 150˚, with no significant differences between age and sex. CONCLUSIONS: Within the limits of this study, the anatomy of the alveolar ridge in the maxillary central incisors showed sufficient capacity as a recipient site for autotransplantation using mandibular premolars, especially in males. These findings serve as a valuable resource for facilitating autotransplantation in children.

What is missing from the sturgeon jaw: Developmental morphology of the upper jaw in Acipenser.

Sturgeons belong to the family Acipenseridae, the most species-rich extant family of Acipenseriformes, a basal actinopterygian group of key importance in assessing the early radiations of the actinopterygians. At the same time, acipenseriforms display unique specializations in the morphology of the snout and jaws which make them a valuable model for studying evolutionary novelties. However, despite a long history of research, the homologies of the snout and the mandibular arch of acipenseriforms remain uncertain preventing further studies on the evolutionary origin of their unique snout and jaw structure, and in particular, of the upper jaw symphysis, the key apomorphy of the group and the preoral snout. In the present study, a detailed description of the upper jaw morphology and development in sturgeons is provided in order to address its composition in terms of the common actinopterygian archetype. Based on the obtained results, the upper jaw of acipenseriforms is assumed to have lost the autopalatine portion, which most likely is represented by the separate cartilages supporting the tentacles. Also, the conventional interpretation of the sturgeon's maxilla as dermopalatine is rejected on the grounds of this bone structure and development. Paedomorphosis is proposed to be the most likely mechanism explaining the evolutionary origin of the upper jaw symphysis and supposed modifications of the snout in sturgeons.

Morphometric Evaluation of Morphological Variations of the Nasopalatine Canal: A Retrospective Study Using Cone-beam Computed Tomography.

AIM: The study aimed to analyze the morphological and anatomical variations of the nasopalatine canal (NPC) using cone-beam computed tomography (CBCT) images and their association with age and gender among the subpopulation of the Qassim region of Saudi Arabia. MATERIALS AND METHODS: The CBCT records of 401 patients referred to the Department of Radiology between January 2020 and July 2023 were randomly selected in the retrospective cross-sectional study. The anatomical characteristics such as the length of the NPC, and the superior and inferior width of the canal, were analyzed. In the sagittal and axial planes, the morphological variants of the shape of the NPC were also investigated. The Statistical Package for the Social Sciences (SPSS) software was used for statistical analyses at a 5% significance level. RESULTS: The study examined the CBCT images of 219 females (54.6%) and 182 males (45.4%) with an overall mean age of 40.17 ± 2.31 years. The overall length of the NPC and superior and inferior canal width were 13.86 ± 2.68 mm, 3.4 ± 1.42 mm, and 4.07 ± 2.06 mm, respectively. Independent t-test revealed that the males had a statistically significant larger superior (3.62 ± 1.78 mm) and inferior canal width (4.33 ± 1.79 mm). In terms of gender, the Chi-square test revealed a statistically significant association (p < 0.01) between the morphological shape of the NPC in the axial and sagittal planes. The heart-shaped (51.4%) and cone-shaped canals (34.2%) were the most frequently recorded NPC in the axial and sagittal planes, respectively. Pearson's correlation found a statistically significant positive relationship (p < 0.05) between the superior and inferior canal width and the canal length. Spearman's correlation revealed a statistically highly significant correlation between the NPC shape in the sagittal plane and gender (p < 0.001). CONCLUSION: The study findings revealed a statistically significant difference in the anatomical and morphological traits of the NPC in the axial and sagittal planes based on gender. The effect of age and gender was found to exhibit significant differences with the NPC parameters. The heart-shaped canal in the axial plane and the cone-shaped canal in the sagittal plane were more prevalent in the study sample. A three-dimensional (3D) examination of the NPC will be crucial to avert challenging circumstances prior to surgical treatments in the anterior maxilla. CLINICAL SIGNIFICANCE: The NPC is a long, narrow canal that can take up to 58% of the buccal bone plate width, and an accurate 3D anatomic illustration of the NPC allows for reliable surgical planning and dental implant placement.

Impact of different cephalometric skeletal configurations on anatomic midface parameters in adults.

OBJECTIVES: Skull morphology and growth patterns are essential for orthodontic treatment, impacting clinical decision making. We aimed to determine the association of different cephalometric skeletal configurations on midface parameters as measured in 3D CT datasets. MATERIALS AND METHODS: After sample size calculation, a total of 240 fully dentulous patients between 20 and 79 years of age (mean age: 42 ± 15), who had received a CT of the skull within the scope of trauma diagnosis or intracranial bleeding, were retrospectively selected. On the basis of cephalometric analysis, using MPR reconstructions, patients were subdivided into three different vertical skull configurations (brachyfacial, mesofacial, dolichofacial) and the respective skeletal Class I, II, and III relationships. Anatomic parameters were measured using a three-dimensional post-processing console: the thickness of the maxillary and palatine bones as well as the alveolar crest, maxillary body and sutural length, width and height of the hard palate, maxillary facial wall thickness, and masseter muscle thickness and length. RESULTS: Individuals with brachyfacial configurations had a significantly increased palatal and alveolar ridge thicknesses compared to those with dolichofacial- or mesofacial configurations. Brachyfacial configurations presented a significantly increased length and thickness of the masseter muscle (4.599 cm; 1.526 cm) than mesofacial (4.431 cm; 1.466 cm) and dolichofacial configurations (4.405 cm; 1.397 cm) (p < 0.001). Individuals with a skeletal Class III had a significantly shorter palatal length (5.313 cm) than those with Class I (5.406 cm) and Class II (5.404 cm) (p < 0.01). Sutural length was also significantly shorter in Class III (p < 0.05). CONCLUSIONS: Skeletal configurations have an impact on parameters of the bony skull. Also, measurable adaptations of the muscular phenotype could result. CLINICAL RELEVANCE: The association between viscerocranial morphology and midface anatomy might be beneficial for tailoring orthodontic appliances to individual anatomy and planning cortically anchored orthodontic appliances.

Evaluation of safe areas for miniscrew use according to various skeletal anomalies with CBCT.

OBJECTIVES: We aimed to determine safe areas to apply miniscrews in the interradicular region of the maxilla and mandible in individuals with various sagittal skeletal malocclusions. MATERIALS AND METHODS: Cone beam-computed tomography images of 159 individuals were used. Individuals were divided into three groups: Class I, Class II, and Class III. In the sagittal plane, 3-6-9-mm apical sections were determined from the alveolar crest apex. The buccal cortical bone thickness, interradicular distance, and buccolingual bone distances were measured. RESULTS: In the buccal cortical bone thickness, we observed statistically significant differences between the classes except for the 1-1 region in the maxilla and all regions and sections in the mandible (p < 0.05). The differences in the buccolingual bone distance between classes were statistically significant, except for the 3-mm and 6-mm sections in the 3-4 and 4-5 regions of the maxilla, the 9-mm sections in the 1-2 and 2-3 regions, the 6-mm and 9-mm sections in the 3-4 region, and the 6-mm section in the 4-5 regions of the mandible (p < 0.05). The differences in the interradicular bone distance were statistically significant between the classes in all regions and sections of the mandible except the 6-mm sections in the 1-2 region and in all sections of the maxilla except the 6-mm sections in the 3-4 region (p < 0.05). CONCLUSIONS: We observed significant differences in the buccal cortical bone thickness, interradicular bone distance, and buccolingual bone distance among individuals. CLINICAL RELEVANCE: Understanding the anatomy of interradicular regions and preventing complications.

Topography of the infraorbital foramen in human skulls originating from different time periods.

BACKGROUND: The infraorbital foramen (IOF) is present on the maxilla under the infraorbital margin. Its identification is essential in various surgical procedures. The main aim of this study was the morphometric assessment of the position of the right and left infraorbital foramina in relation to specific structural elements of the facial skeleton, their width and direction, and also the determination of the location of these foramina above maxillary teeth in examined male skulls (belonging to European populations) dated to the beginning of the 20th century and the medieval and post-medieval period. This aim concerned also the assessment of the symmetry of the examined foramina (their location and size). An additional goal was to determine differences between the cranial samples concerning the analysed traits. MATERIALS AND METHODS: The six metric and two non-metric traits concerning the IOF were collected from the male cranial samples including modern skulls (n = 87), the medieval and post-medieval skulls (from 13th centuries and 15-17th centuries, respectively; n = 47) obtained from archaeological excavations in Wroclaw, and the sample of the medieval skulls (11-13th centuries, n = 100) from Sypniewo. The sex and age of the specimens were determined using the standard methodology. The appropriate statistical analysis was performed. RESULTS: Significant differences were established for three traits (taken from the left and right side) in the case of modern skulls (diameter of IOF, its distance to the midline, and zygomaticomaxillary suture) and one in the case of medieval skulls from Sypniewo (distance to the midline). In all of the cranial samples IOF most frequently occurred above the first upper molar. The greater diameter of IOF and its shorter distance to the alveolar crest and nasal notch were observed in non-modern skulls compared to modern skulls. CONCLUSIONS: The results of this study provide new additional data on the topography of IOF and its asymmetry, confirm the presence of both geographical and chronological differences between populations, and can be used in dental practice, and forensic odontology in the analysis of archaeological bone materials.

Estudio Anatómico y Prevalencia del Canalis sinuosus Evaluado Mediante Cone Beam CT en Pacientes Chilenos / Anatomical Study and Prevalence of Canalis sinuosus Evaluated by Cone Beam CT in Chilean Patients

Canalis sinuosus, canal intraóseo localizado en región maxilar anterior, contiene elementos vasculonerviosos alveolares anterosuperiores. Diversas intervenciones en región maxilar anterior como colocación de implantes, exodoncias, instalación de microtornillos ortodóncicos, procedimientos quirúrgicos, entre otros, pueden comprometer al Canalis sinuosus y/o sus canales accesorios dañando los elementos contenidos en su interior causando complicaciones como hemorragias, parestesia, disestesia, etc. Dado el gran desconocimiento de su existencia, el Canalis sinuosus frecuentemente es confundido con lesiones patológicas y/o endodónticas. Clásicamente la literatura lo describe como una variación anatómica variación anatómica, sin embargo, presenta elevadas prevalencias (51,7 %-100 %), siendo cuestionada esta aseveración. Determinar prevalencia y característica s anatómicas del Canalis sinuosus mediante Cone Beam CT en pacientes chilenos del centro radiológico IMAPROX® entre 2017- 2021. Análisis retrospectivo de 220 CBCT maxilares anonimizados, considerando variables sexo, presencia del Canalis sinuosus, Canalis sinuosus uni/bilateral, diámetro mayor del Canalis sinuosus, presencia/número de accesorios. Análisis estadístico uni y bivariado. 100 % de prevalencia del Canalis sinuosus en ambos sexos, presencia bilateral 100 %. Diámetro mayor promedio del Canalis sinuosus: 2,58 mm. El 76,8 % presentó accesorios, siendo más prevalente la presencia de 2 CA (34,1 %). Una estructura anatómica normal habitual debe presentar sobre 50 % de prevalencia para ser considerada como tal, pero no hay consensos en criterios empleados para definir variación anatómica o estructura anatómica normal habitual. Literatura describe al Canalis sinuosus como variación anatómica, pero estudios actuales muestran elevadas prevalencias: Rusia 67 %, Brasil 88 %, Turquía, Colombia y Chile 100 %. Este estudio encontró 100 % de prevalencia, sugiriendo que Canalis sinuosus es una estructura anatómica normal habitual. Sin embargo, Canalis sinuosus es poco conocido asociándose a numerosas complicaciones por procedimientos odontológicos y/o quirúrgicos en RMA pudiendo generar hemorragias, parestesia/disestesia, dolor agudo, etc. Elevadas prevalencias reportadas sugieren que Canalis sinuosus es una estructura anatómica normal habitual y no una variación anatómica, pero se requieren más estudios y consensos para aseverarlo. Es de relevancia clínica conocer la existencia y localización del Canalis sinuosus para evitar complicaciones.

Canalis sinuosus, an intraosseous canal located in the anterior maxillary region, contains anterosuperior alveolar vascular-nervous elements. Various interventions in anterior maxillary region such as implant placement, extractions, installation of orthodontic microscrews, surgical procedures, among others, can compromise the Canalis sinuosus and/or its accessory canals, damaging the elements contained inside, causing complications such as bleeding, paresthesia, dysesthesia, etc. Given the great ignorance of its existence, Canalis sinuosus is frequently confused with pathological and/or endodontic lesions. Classically, the literature describes it as an anatomical variation, however, it presents high prevalence (51.7 %-100 %), this assertion being questioned. Objective: to determine the prevalence and anatomical characteristics of Canalis sinuosus using Cone Beam CT in Chilean patients from the IMAPROX® radiological center between 2017-2021. Retrospective analysis of 220 anonymous maxillary CBCT, considering variables sex, presence of Canalis sinuosus, uni/bilateral Canalis sinuosus, largest diameter of Canalis sinuosus, presence/number of accessory canals. Univariate and bivariate statistical analysis. The 100 % prevalence of Canalis sinuosus in both sexes, 100 % bilateral presence. Canalis sinuosus average major diameter: 2.58 mm, 76.8 % presented accessory canals, with the presence of 2 accessory canals being more prevalent (34.1 %). A habitual normal anatomical structure must have a prevalence of over 50 % to be considered as such, but there is no consensus on the criteria used to define anatomical variation or normal anatomical structure. Literature describes Canalis sinuosus as anatomical variation, but current studies show high prevalence: Russia 67 %, Brazil 88 %, Turkey, Colombia and Chile 100 %. This study found 100 % prevalence, suggesting that Canalis sinuosus is an normal anatomical structure. However, Canalis sinuosus is little known as it is associated with numerous complications from dental and/or surgical procedures in anterior maxillary region, which can cause bleeding, paresthesia/ dysesthesia, acute pain, etc. High reported prevalences suggest that Canalis sinuosus is an normal anatomical structure and not an anatomical variation, but more studies and consensus are required to confirm this. It is clinically relevant to know the existence and location of Canalis sinuosus to avoid complications.

A morphological study and the variability in the number of infraorbital foramina in the African green monkey (Grivet) (Chlorocebus aethiops) using microcomputed tomography.

Knowledge of the nonhuman primate morphology and anatomy related to craniofacial mechanoreception is essential for a fundamental understanding of the incidents that have occurred during the evolution of craniofacial features. The present study focuses on the variability in the number of infraorbital foramina and associated anatomical structures such as the infraorbital canal (IOC) and the infraorbital groove (IOG), as they are considered to play an important role in the behavioral ecology of these animals. A total of 19 skulls of Chlorocebus aethiops were analyzed. The number of infraorbital foramina was assessed macroscopically using a magnifying glass and a small diameter probe. Three dimensional (3D) projections and morphometric analysis of the infraorbital foramina, IOCs, and IOGs were performed using microcomputed tomography (micro-CT) for two skulls that represent one of the most common morphological types. Regardless of sex and body side, the most common morphological type observed in the studied species is the presence of three infraorbital foramina. The IOC takes a funnel or pinched shape. 3D projections were made to assess the course of the infraorbital vascular and nerve bundles in selected individuals. The results indicate a high morphological diversity within the species, although there appears to be a consistent distribution pattern of infraorbital neurovascular bundles in species of the Cercopithecidae family. The use of X-ray micro-CT allowed 3D visualization of the maxillary region to determine the variability of the infraorbital foramina and to track the division of the infraorbital neurovascular bundle in the case of the most common macroscopic expression of the number of the infraorbital foramen in C. aethiops, as well as the morphometric of the IOCs and IOGs which are related to mechanoreception of the primate's snout.

A rare find of a maxillary third molar with five roots: a case report of an unusual morphology.

Third molars are frequently absent or impacted; their unpredictable prevalence and morphology, with frequent anatomical variations, is a challenge for the practitioner. The number of roots of the upper third molars vary from one to five, but five roots upper third molars' cases are extremely rare. The case reported here is of a normotrophic male patient, with no significant general medical history, having extracted an impacted maxillary upper molar, with an unusual position and dimensions and five completely separated formed roots, orientated in diverse directions. It highlights the importance of using the correct surgical technique, without excessive pressure, for avoiding the fracture of the maxillary tuberosity, the displacement of the molar into the pterygopalatine fossa or the opening of the maxillary sinus, especially in the absence of good quality imagistic information like cone-beam computed tomography. The case presented in this paper is very rare and highlights the significance of anatomical knowledge, which is mandatory for managing these cases, to avoid trauma, accidents, and complications and to maintain an optimal time of extraction, since such variations occur, and the conventional radiographs do not offer enough data to clarify the diagnosis.

The maxillary canal of the titanosuchid Jonkeria (Synapsida, Dinocephalia).

The maxillary canal of the titanosuchid dinocephalian Jonkeria is described based on digitised serial sections. We highlight that its morphology is more like that of the tapinocephalid Moschognathus than that of Anteosaurus. This is unexpected given the similarities between the dentition of Jonkeria and Anteosaurus (i.e., presence of a canine) and the fact that the branching pattern of the maxillary canal in synapsids usually co-varies with dentition. Hypotheses to account for similarities between Jonkeria and Moschognathus (common ancestry, function in social signalling or underwater sensing) are discussed. It is likely that the maxillary canal carries a strong phylogenetic signal, here supporting the clade Tapinocephalia.

Microsurgical Anatomy of the Incisive Canals.

BACKGROUND: The purpose of this study was to investigate the structure of the incisive canal using dry maxillae harvested from human cadavers. METHODS: Seven dry maxillae were harvested from adult Caucasian human cadavers. The incisive canals in all specimens were observed from an intraoral viewpoint with the naked eye and under a surgical microscope with 20× magnification. RESULTS: All specimens had a single incisive foramen leading to different numbers of canals. Two specimens had a single canal (Type I), two were double (Type II), and three had triple canals (Type III). In both type I specimens, the canal was centered in the incisive foramen. Type II had a septum between the two canals. This septum was irregular in shape near the entrance of the canal but smooth inside the canal. The canals were positioned asymmetrically within the foramen. Type III had two septa between the three canals. Again, those located near the entrance of the canal were irregular while those inside the canal were smooth. The orientation of the lumina differed from one another in the type III canals. CONCLUSION: The study identified morphological variations in the anatomy of the incisive canal, underscoring the importance of pre-surgical planning in the administration of local anesthesia, placement of dental implants, or removal of impacted teeth in the anterior maxillary region.

Heritability of cephalometric variables of airway morphology in twins with completed active growth.

BACKGROUND: The interplay between genetic and environmental impacts on dental and facial morphology has been widely analyzed, but little is known about their relative contributions to airway morphology. The aim of this study was to evaluate the genetic and environmental influences on the cephalometric variables of airway morphology in a group of postpubertal twins with completed craniofacial growth. MATERIALS AND METHODS: The materials comprised lateral head cephalograms of 94 pairs of twins (50 monozygotic, 44 dizygotic) with completed craniofacial growth. Zygosity was determined using 15 specific DNA markers. The computerized cephalometric analysis included 22 craniofacial, hyoideal, pharyngeal structural linear and angular variables. Genetic analysis and heritability estimation were performed using maximum likelihood genetic structural equation modeling (GSEM). Principal component analysis (PCA) was used to assess the correlations between cephalometric measurement variables. RESULTS: Upper airway dimensions showed moderate to high genetic determination (SPPW-SPP and U-MPW: a2 = 0.64 and 0.5, respectively). Lower airway parameters showed only common and specific environmental determination (PPW-TPP a2 = 0.24, e2 = 0.38; LPW-V c2 = 0.2, e2 = 0.63; PCV-AH c2 = 0.47, e2 = 0.28). The relationship between the maxilla and the hyoid bone (for variables PNS-AH, ANS-AH d2 = 0.9, 0.92, respectively) showed very strong additive genetic determination. The size of the soft palate was affected by additive and dominant genes. Its length (SPL) was strongly influenced by dominant genes, while its width (SPW) showed a moderate additive genetic influence. Owing to correlations in the behavior of variables, the data could be expressed in 5 principal components that jointly explained 36.8% of the total variance. CONCLUSIONS: The dimensions of the upper airway are strongly determined by genes, while the parameters of the lower airway depend mainly on environmental factors. TRIAL REGISTRATION: The protocol has been approved by the Kaunas Regional Ethical Committee (No. BE - 2-41., May 13, 2020).

Neanderthal child's maxilla from Baume Moula-Guercy (Soyons, Ardèche, France).

This article provides an ontogenetically-based comparative description of the Guercy 3 partial child's maxilla with Rdm2 -RM1 and unerupted RI2 -RP4 from Baume Moula-Guercy (MIS 5e) and examines its affinities to European and Middle Eastern Middle-to-Late Pleistocene (≈MIS 14-MIS 1) Homo. Description of the Guercy 3 maxilla and dentition (7.0 year ± 0.9 month) is based on observations of original fossils, casts, CT scans, literature descriptions, and virtual reconstructions. Our ontogenetic sample comprises a Preneanderthal-Neanderthal group and a Homo sapiens group. These groups are subdivided into (1) Preneanderthals (≈MIS 14-9), Early Neanderthals (MIS 7-5e), and Late Neanderthals (MIS 5d-3), and (2) Middle (MIS 5), Upper (MIS 3-2), and Late Upper Paleolithic (≈MIS 1), and recent H. sapiens. Standard techniques were employed for measurements and developmental age determinations.The Guercy 3 maxilla lacks changes found in Late Neanderthals, including the positioning of the root of the zygomatic process, infraorbital and nasal plates, premaxilla, buccal and labial alveolus, maxillary sinus, nasal cavity, and verticality of anterior tooth implantation. The morphology of the Guercy 3 maxilla more closely approximates that of Sima de los Huesos Preneanderthals, while the dentition more closely approximates the Early-Late Neanderthal condition. Maxillary remains of children and juveniles between MIS 14-MIS 5e are rare, and the available sample is fragmentary and distorted. Although fragmentary, the Guercy 3 maxilla is undistorted and provides new insights into the evolution of the midface in Neanderthals.

Estimating the occurrence of labial bone perforation and implantation into the maxillary sinus maxillary premolars based on the morphology of maxillary premolars: A clinical study.

STATEMENT OF PROBLEM: Previous studies have classified the sagittal root position of the maxillary anterior teeth and measured buccal plate thickness to aid treatment planning. A thin labial wall and buccal concavity may cause buccal perforation, dehiscence, or both in maxillary premolars. However, data on the restoration-driven principle to classify the maxillary premolar region are lacking. PURPOSE: The purpose of this clinical study was to investigate the occurrence of labial bone perforation and implantation into the maxillary sinus between various tooth-alveolar classifications with respect to the crown axis in maxillary premolars. MATERIAL AND METHODS: Cone beam computed tomography images of 399 participants (1596 teeth) were analyzed to determine the probability of labial bone perforation and implantation into the maxillary sinus when associated with variables that included tooth position and tooth-alveolar classification. RESULTS: The morphology in the maxillary premolars was classified as straight, oblique, or boot-shaped. The first premolars were 62.3% straight, 37.0% oblique, and 0.8% boot-shaped, and labial bone perforation occurred in 4.2% (21 of 497) of the straight, 54.2% (160 of 295) of the oblique, and 83.3% (5 of 6) of the boot-shaped first premolars when the virtual implant was 3.5×10 mm. When the virtual tapered implant was 4.3×10 mm, labial bone perforation occurred in 8.5% (42 of 497) of the straight, 68.5% (202 of 295) of the oblique, and 83.3% (5 of 6) of the boot-shaped first premolars. The second premolars were 92.4% straight, 7.5% oblique, and 0.1% boot-shaped, and labial bone perforation occurred in 0.5% (4 of 737) of the straight, 33.3% (20 of 60) of the oblique, and 0% (0 of 1) of the boot-shaped, respectively, when the virtual tapered implant was 3.5×10 mm; and labial bone perforation occurred in 1.3% (10/737) of the straight, 53.3% (32/60) of the oblique, and 100% (1/1) of the boot-shaped second premolars when the virtual tapered implant was 4.3×10 mm. CONCLUSIONS: When an implant is placed in the long axis of a maxillary premolar, the tooth position and tooth-alveolar classification should be considered when assessing the risk of labial bone perforation. Attention should be paid to the implant direction, diameter, and length in the oblique and boot-shaped maxillary premolars.

Evaluation of the morphology of accessory canals of the canalis sinuosus via cone-beam computed tomography.

PURPOSE: This study aims to assess the presence of accessory canal (AC) associated with canalis sinuous (CS), describing their frequency, lateralization, location, direction, and measurements in cone beam computed tomography (CBCT). METHODS: Axial, coronal, sagittal, and cross-sectional reconstructions were analyzed in 248 CBCT images and the presence of CS, the presence of AC associated with CS, the lateralization, localization, and direction course of AC associated with CS was evaluated. CS diameter, AC diameter, the distance between the nasal cavity floor and CS (M1), CS and the buccal cortical bone (M2), and CS and the alveolar ridge (M3) were measured. RESULTS: CS was detected in all CBCT scans as bilaterally. The prevalence of AC associated with CS was 35.5%. There was a significant difference between dental status anthe d presence of AC associated with CS. There was a significant difference between gender, dental status, and lateralization of AC associated with CS. While M1 was greater in male patients than females, M3 was greater in female patients. M2 and M3 were greater in younger patients. CONCLUSION: Clinicians performing surgical procedures should keep in mind that anatomical variations of the vascular nerve bundle may be seen. M1, M2, and M3 measurements can be affected by gender, age, and dental status.

Radiological examination of the relationship between the pterygomaxillary junction and fracture pattern.

BACKGROUND: Le Fort 1 (LF1) osteotomies are widely used to correct midface deformities. To move the maxilla freely, the ptery-gomaxillary junction (PMJ) must be separated. When performing this osteotomy, the pterygoid plate must remain intact. The objective of this study was to evaluate relationship between the anatomical features of the PMJ and fracture patterns in LF1 osteotomy. METHODS: Pre-operative and post-operative cone-beam computed tomography images of 41 patients (82 samples) who have undergone LF1 osteotomy surgery were radiologically evaluated. Morphologic measurements of the pterygomaxillary fissure area and pterygoid plate were carried out. Moreover, pterygomaxillary separation was divided into the clean-cut, maxillary sinus, and pterygoid plate fracture types. RESULTS: Statistically significant difference was observed between clean-type fracture and pterygoid plate fracture groups' thickness of the pterygoid process and thickness of the pterygomaxillary region. CONCLUSION: Anatomical variations make it difficult to separate the PMJ properly. Low thickness of PMJ increases the risk of unwanted fractures; however, according to our experience, the use of an osteotome with an incorrect angle, excessive force, and inexperienced surgeons can also cause undesirable pterygoid plate fractures.

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.

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.

The morphology of permanent maxillary first molars evaluated by cone-beam computed tomography among a Yemeni population.

BACKGROUND: The study's objective was to use CBCT to ascertain the root and root canal anatomy of the permanent maxillary first molars in a Yemeni population. It was considered how gender affected the prevalence of root canal morphology. METHODS: A sample of 373 CBCT records of maxillary permanent first molars belonging to 373 Yemeni individuals (162 males and 211 females) aged between 12 and 65 years were included in this study. Using CBCT on the teeth, the root form and canal morphology for each root based on Vertucci's classification were evaluated. The distribution of MB2 occurrence was documented. The prevalence and resemblance of the men and females were investigated. The Chi-square test was performed to evaluate the findings. RESULTS: Of the 373 maxillary first molars studied, the three separated root form was found in 94.9% of the studied MFMs while the two fused and one separate root form was found in 4.5%. The majority of the three-rooted MFMs (82.6%) had more than three root canals (four canals in 77.2% and five canals in 5.4%). The prevalence of MB2 was as high as 82.3% of the three-rooted MFMs. Vertucci type II configuration was the most frequent canal type (25%) followed by Vertucci type III (23.1%) and Vertucci type I (17.7%) in the mesiobuccal root. Vertucci type I was the most prevalent canal configuration in the distobuccal root and palatal root of the three-rooted MFMs (96% and 99.5%, respectively). CONCLUSIONS: The maxillary first molars' root canal morphology indicated notable variations among a Yemeni population. The maxillary first molars of most of the Yemeni participants in this study had three roots and four canals. In light of the high occurrence of MB2 (82.3%) in permanent maxillary first molars, our findings emphasize the need of searching for and using cutting-edge techniques to locate the MB2 canals. Males outnumbered females in proportion.