Relationship between vertical facial pattern and brain structure and shape.

OBJECTIVES: Dolichofacial (long-faced) and brachyfacial (short-faced) individuals show specific and well-differentiated craniofacial morphology. Here, we hypothesise that differences in the basicranial orientation and topology between dolicho- and brachyfacial subjects could be associated with differences in the supporting brain tissues. MATERIAL AND METHODS: Brain volumes (total intracranial, grey matter, and white matter volume), cortical thickness, and the volumes and shapes of fifteen subcortical nuclei were assessed on the basis of magnetic resonance imaging in 185 subjects. Global, voxel-wise and shape analyses, as well as multiple regression models, were generated to evaluate the association between vertical facial variations (dolicho- and brachyfacial spectrum) and brain morphology. RESULTS: Several differences in brain anatomy between dolicho- and brachyfacial subjects, along with relevant associations between vertical facial indices and brain structure and shape, were found. The most relevant finding of this study is related to the strong association of vertical facial indices with the volumes and shapes of subcortical nuclei, as the dolichofacial pattern increased, the bilateral hippocampus and brain stem expanded, while the left caudate, right pallidus, right amygdala, and right accumbens decreased in volume. CONCLUSIONS: Long- and short-faced human subjects present differences in brain structure and shape. CLINICAL SIGNIFICANT: The results of our study increase the clinician's knowledge about brain structure in dolicho- and brachyfacial patients. The findings could be of interest since the affected brain areas are involved in higher cognitive functions in humans, including language, memory, and attention.

Maxillary Sinus and Surrounding Bone Anatomy With Cone Beam Computed Tomography After Multiple Teeth Loss: A Retrospective Multicenter Clinical Study.

PURPOSE: The aim of this multicenter study was to examine the residual alveolar bone anatomy and sinus mucosa pattern at maxillary sinus regions in multiple teeth loss. MATERIALS AND METHODS: This study was conducted with cone beam computed tomography images of 518 patients (267 females and 251 males) with multiple posterior maxillary teeth loss. Variables associated with sinus membrane (SM), sinus dimensions, ostium, septa, sinus neighborhood, alveolar bone height and ridge width, posterior superior alveolar artery, and adjacent roots were evaluated. RESULTS: No (58.2%) or flat (19.3%) thickening morphology was detected at most of the SMs. Membrane thickening and mucosal-like morphology was more prevalent for male patients (P = 0.005). The mean sinus width was relatively low (3.64 ± 3.33 mm) at the 5-mm level and showed an expected increase toward upper levels. Most of the sinus spaces were dimensionally average (39.5%) or wide (44.7%), and no effect of gender was observed in terms of sinus dimensions (P > 0.05). CONCLUSION: Multiple teeth loss plays a role in creating an imaginary sinus anatomy constituted of a relatively narrow space compared with single-tooth loss cases, from 3.6-mm mean coronal width to 11.3 mm in the apical portion.

Evaluation of Single Tooth Loss to Maxillary Sinus and Surrounding Bone Anatomy With Cone-Beam Computed Tomography: A Multicenter Study.

BACKGROUND: Posterior maxillary tooth loss may complicate the implant treatment due to the alterations in alveolar anatomy and maxillary sinus pneumatization. This study aimed to comprehensively examine the anatomical structure of this region from cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: The posterior maxilla regions with single tooth loss were analyzed by dividing the variables into 3 subgroups from images of 597 patients chosen from 1160 CBCTs. Variables associated with sinus membrane (SM), sinus dimensions, ostium, septa, sinus neighborhood, alveolar bone height (ABH) and width (RW), posterior superior alveolar artery (PSAA), and adjacent roots were evaluated. RESULTS: The majority of the patients demonstrated 0 to 5 mm membrane thickness. Irregular SM thickening was lower for female patients. While females showed higher number of narrow sinus, males had higher RW than females. Sinus augmentation classification showed negative correlation with ABH, root-tip sinus floor and edentulous site classification. Posterior septa height was correlated with number of septa and ABH. PSAA diameter and location were also correlated between each other. CONCLUSION: The present results define formation of a sinus space with 11 mm coronal and 16 mm apical width after single tooth loss. A flat or semispherical thickening around 4 mm is usual in most cases with 51% possibility of anterior septum existence. A ridge anatomy, around 7.5 mm ABH and 7.2 to 9.3 RW from coronal to apical, complements this anatomy. Further studies are needed to clarify the reasons behind the SM and crestal anatomy variations between genders.

Inferior alveolar nerve trajectory, mental foramen location and incidence of mental nerve anterior loop

Background: Injury of the inferior alveolar nerve (IAN) is a serious intraoperative complication that may occur during routine surgical procedures, such as dental implant placement or extraction of impacted teeth. Thus, the purpose of this study was to analyze the trajectory of the mandibular canal (MC), the location of the mental foramen (MF) and the presence and extension of an anterior loop of the mental nerve (AL). Study Design: In this cross-sectional study, a total of 348 CBCTs were analyzed. Distances from MC to the surface of the basal, medial and lateral cortical of the mandible were measured at the level of the second molar, first molar and second premolar. Location of the MF relative to the apices of the premolars, as well as incidence and anterior extent of the AL were also determined. Results: Significant and clinically relevant correlations were found between the position of the MC in women, which was located more caudal (r=-0.219, p=0.007; r=-0.276, p< 0.001; right and left, respectively) and lateral (r=-0.274, p=0.001; r=-0.285, p< 0.001; right and left, respectively), particularly at the level of the premolars. Additionally, the presence (r=-0.181, p=0.001; r=-0.163, p=0.002; right and left, respectively) and anterior extension (r=-0.180, p=0.009; r=-0.285, p=0.05; right and left, respectively) of the AL was found to be inversely correlated with the age of the patient. Conclusions: This analysis of a Caucasian population has found that the older the patient, the lower the incidence of the loop and the shorter its anterior extension (AU)

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Maxillary Sinus Dimensions Decrease as Age and Tooth Loss Increase.

OBJECTIVE: To investigate the correlation between patient-dependent variables and dimensional variations of the maxillary sinus. METHODS: In this cross-sectional study, a total of 394 individual cone-beam computed tomography scans were evaluated by one calibrated examiner to measure the total volume of the maxillary sinus, the distance between the medial and the lateral walls at 5, 10, and 15 mm vertically from the sinus floor, the height of septa (if present), and the height of the maxillary sinus cavity from both the alveolar crest and the sinus floor to the meatus. Recorded patient-dependent variables were age, gender, and edentulism status. RESULTS: Total maxillary sinus volume was significantly smaller in completely and partially edentulous patients than in dentate subjects. This finding was influenced by age, as older patients exhibited less volume, regardless of gender and edentulism status. Age showed an indirect correlation with the distance to the meatus, the sinus volume, and the mediolateral dimensions. Additionally, the prevalence of accessory meatus in this population was 29.19%. CONCLUSIONS: The dimensions of the maxillary sinus are influenced by age and edentulism status being reduced by aging and tooth loss.

Spheno-Occipital Synchondrosis Fusion Correlates with Cervical Vertebrae Maturation.

The aim of this study was to determine the relationship between the closure stage of the spheno-occipital synchondrosis and the maturational stage of the cervical vertebrae (CVM) in growing and young adult subjects using cone beam computed tomography (CBCT). CBCT images with an extended field of view obtained from 315 participants (148 females and 167 males; mean age 15.6 ±7.3 years; range 6 to 23 years) were analyzed. The fusion status of the synchondrosis was determined using a five-stage scoring system; the vertebral maturational status was evaluated using a six-stage stratification (CVM method). Ordinal regression was used to study the ability of the synchondrosis stage to predict the vertebral maturation stage. Vertebrae and synchondrosis had a strong significant correlation (r = 0.89) that essential was similar for females (r = 0.88) and males (r = 0.89). CVM stage could be accurately predicted from synchondrosis stage by ordinal regression models. Prediction equations of the vertebral stage using synchondrosis stage, sex and biological age as predictors were developed. Thus this investigation demonstrated that the stage of spheno-occipital synchondrosis, as determined in CBCT images, is a reasonable indicator of growth maturation.

Maxillary Sinus Dimensions With Respect to the Posterior Superior Alveolar Artery Decrease With Tooth Loss.

BACKGROUND: The posterior superior alveolar (PSA) artery is frequently encountered in the area where the lateral osteotomy is performed during direct sinus augmentation procedures. OBJECTIVE: To investigate the correlation between patient-dependent variables and measurements related to PSA using cone beam computed tomography (CBCT) data. METHODS: Three hundred ninety-four CBCT scans were evaluated to assess the PSA artery diameter and distances to the sinus floor and to alveolar crest. Patient's age, gender, and edentulism status were recorded. RESULTS: The PSA artery tends to be wider in older patients. Distances to the sinus floor or the alveolar crest tend to be shorter in women and in partially and completely edentulous patients. Also, as those distances decrease, the mediolateral width of the sinus increases. CONCLUSION: Tooth loss leads to maxillary sinus vertical collapse with respect to the PSA artery. The position of the artery is stable; so, the mediolateral dimensions at different heights from the floor increase. PRACTICAL IMPLICATIONS: The reduced distances from the PSA to the sinus floor and the alveolar crest in edentulous patients potentially increase the risk of injury during maxillary sinus lift. Additionally, when the distance to the sinus floor decreases, the mediolateral dimensions of the sinus at different heights increase, which may complicate the technique and challenge the outcomes.

Evaluation of mandibular lingual foramina related to dental implant treatment with computerized tomography: a multicenter clinical study.

BACKGROUND: Bleeding can be one of the severe complications during implant placement or other surgeries. Presurgical assessment of the area should be performed precisely. Thus, we examined lingual vascular canals of the mandible using dental computerized tomography (CT); define the anatomical characteristics of canals and the relationship with mandibular bone. METHODS: One thousand sixty-one foramina in 639 patients, in 5 dental clinics, were included in this multicenter study. Distance between crest and lingual foramen, tooth apex and lingual foramen, distance from mandibular border, diameter of lingual foramen, canal type, anastomosis, and location of foramen were examined. RESULTS: Foramen was 18.33 ± 5.45 mm below the bony crest and 17.40 ± 7.52 mm from the mandibular border, with men showing larger measurements. The mean diameter of lingual foramina was 0.89 ± 0.40 mm; 76.8% canal type was mono; 51.8% patients presented with median lingual canal-foramen (MLC) and 21.1% with lateral lingual foramen. Diameter of MLC was statistically larger. CONCLUSIONS: With a large sample group, results represented that lingual foramina could be visualized with dental CT, providing useful data for mandibular implant surgeries. Findings suggest that vascular canals and several anastomoses exist in the anterior mandible extending through premolar and molar regions as well. It is imperative to consider these vessels with the dental CT before and during the mandibular surgery to prevent threatening hemorrhage.

Tobacco consumption induces alveolar crest height loss independently of mandibular bone mass and bone density.

AIM: To investigate the relationship of tobacco consumption with alveolar crest height (ACH) loss and mandibular bone mass estimated by digital panoramic radiography and cone-beam computed tomography (CBCT). MATERIAL AND METHODS: We studied 315 patients (43.2% [n = 136] men and 56.8% [n = 179] women) with mean age of 36.6 ± 5.3 (range 21-30 years (16.2%), range 31-46 years (83.8%); 9% (n = 71) were smokers (>10 cig./day). A mean of 13.0 ± 2.0 mandibular teeth were present: 37.5% of patients had 6-12 teeth and 62.5% 13-16 teeth. We analyzed 315 digital panoramic radiographs (2D) and calculated the ACH, mandibular cortical width, and basal and alveolar bone gray level values. ACH and bone density were also measured on CBCT (3D) in the 110 patients scheduled for implantation. RESULTS: In the univariate analysis, ACH loss was greater in older patients (P = 0.012) and in those with fewer mandibular teeth (P < 0.001) and showed a relationship with tobacco consumption that was close to significant (P = 0.079). In the multivariate analysis, the number of mandibular teeth (P < 0.001) and tobacco consumption (P = 0.048) were significantly associated with ACH. Alveolar and basal bone densities were associated, respectively, with number of mandibular teeth (P = 0.012) and cortical width (P = 0.030). CONCLUSION: In a Caucasian population aged 21-46 years, tobacco consumption was significantly associated with ACH loss. However, ACH loss showed no significant relationship with mandibular bone mass estimated either as mandibular cortical width index or bone density on digital panoramic radiographs or as bone density on CBCT. ACH loss was a local event independent of mandibular bone mass status.

Is there a gender difference in anatomic features of incisive canal and maxillary environmental bone?

OBJECTIVES: The effect of gender on anatomic structures and various body systems were illustrated in the literature. The purpose of this study was to identify the influence of gender and tooth loss on incisive canal characteristics and buccal bone dimensions in the anterior maxilla. MATERIALS AND METHODS: Computed tomographies (CTs) of 417 male and 516 female patients in four dental clinics were included in this study. The diameter and the length of the incisive canal; width and the length of the bone anterior to the canal; palatal bone length, root length, and root width of the central incisor teeth were measured and recorded from CT sections. RESULTS: Mean incisive canal length was 11.96 ± 2.73 mm and 10.39 ± 2.47 mm in men and women, respectively, (P < 0.05). In men, mean canal diameter was 2.79 ± 0.94 mm whereas in women it was 2.43 ± 0.85 mm and this difference was statistically significant (P < 0.05). Men had significant higher buccal bone dimensions (length and width of the bone anterior to the canal) than women. Absence of teeth in the anterior maxilla decreased incisive canal length and buccal bone dimensions; however, canal diameter remain unchanged. CONCLUSIONS: Present results suggested a gender related differences in anatomic features of incisive canal and surrounding buccal bone. In addition, crestal canal diameter, buccal bone length, and thickness parameters might be different in distinct countries.

Evaluation of maxillary incisive canal characteristics related to dental implant treatment with computerized tomography: a clinical multicenter study.

BACKGROUND: A close anatomic relationship between the incisive canal and the roots of the central maxillary incisors should be kept in mind during dental-implant treatment in the anterior maxilla. The aim of the present study is to analyze incisive canal characteristics on computed tomography (CT) sections and to evaluate its relation to bone anterior to the canal with regard to dental implantation. METHODS: A total of 933 partially edentulous and/or edentulous patients scheduled for implant insertion in four dental clinics enrolled in the present study. The following were measured and recorded from CT sections for analysis: 1) diameter and length of the incisive canal; 2) width and length of the bone anterior to the canal; 3) palatal bone width and length; and 4) root width and length of the central incisor. RESULTS: Mean canal length was 10.86 ± 2.67 mm, and mean diameter was 2.59 ± 0.91 mm. Canal length was shortened in edentulous anterior maxilla compared to dentate maxilla. However, canal diameter did not show any difference between dentate and edentulous groups. Males had a longer and wider incisive canal than females. Canal shape was mostly cylindrical in 40.73% of images. No correlation was found with mean canal length and mean canal diameter according to age. CONCLUSIONS: Although variations exist in every patient, the findings from this study suggest that sex and dental status are important factors that can affect incisive canal characteristics and amount of bone anterior to the canal. Clinicians should perform careful planning using CT scans before performing dental implant surgeries in premaxillary region.