RESUMEN
The purpose of this study was to analyze the risk of the maxillary sinus lift technique and the correlation between the thickness of the gingiva, maxillary sinus membrane, and the maxillary sinus lateral wall. Cone-beam computerized tomograhy (CBCT) records of 32 adult dentate patients (10 male/22 female) were analyzed. The gingival thickness records of the dental units were compared with the thickness measurements of the membrane and lateral wall of the maxillary sinus. The gingival biotypes varied between 1.1 mm (thin) and 1.6 mm (thick), with a small association with sex. The thickness of the sinus membrane presented a small association between sexes (0.2 mm, female/0.3 mm, male) and gingival biotypes (Cohen d = .52). The lateral wall presented a weak association between the biotypes (1.3 mm, thin/1.1 mm, thick). There was also no correlation between the membrane and lateral wall (r = -.22). The volume dimension related to the graft area of the sinus was 4 mm3 for men and 5 mm3 for women. There was a weak correlation of gingival thickness compared with membrane thickness and lateral wall of the sinus (r = .304/r = -.31). Gingival thickness does not appear to be a reliable thickness predictor of the membrane or lateral wall of the maxillary sinus. The analysis of maxillary sinus anatomical structures through CBCT is the most reliable technique to identify the thickness of the membrane and lateral wall of the maxillary sinus before surgery. We believe that new studies are necessary to confirm our findings.
Asunto(s)
Tomografía Computarizada de Haz Cónico , Encía , Adulto , Femenino , Encía/diagnóstico por imagen , Humanos , Masculino , Maxilar/diagnóstico por imagen , Maxilar/cirugía , Seno Maxilar/diagnóstico por imagen , Seno Maxilar/cirugíaRESUMEN
We calculated the inter-radicular distances between the canine, and first and second premolars, of human mandibles and the thickness of the cortical bone at adjacent sites using computed tomographic (CT) imaging, and assessed the precision of the dimensional assessment made by CT compared with the same measurement made directly with calipers. We examined 100 adult cadaveric dentate human hemimandibles. At the level at which monocortical screws are inserted to place miniplates according to the current technique used to treat mandibular fractures, points A, B, and C referred to the canine, and first and second premolars, and were marked to calculate the level of the CT slice and as the reference for sectioning of the hemimandible. Our findings showed that there was no significant difference in the inter-radicular distance or in the thickness of cortical bone between the sides of the mandible. The vestibular cortical bone was less than 3.0mm thick in 91 of the samples. In 98 of the samples the inter-radicular distance between the canine and the first and second premolars was more than 2mm. There was no significant difference in micrometric precision between the dimensional assessment on CT and direct measurement using a caliper. In the region of the mental foramen the screws have cortical bone less than 3mm thick in which to be anchored. The inter-radicular distance suggests that there is a minimal risk of radicular injury when miniscrews are inserted between the alveolar structures. CT is a reliable tool for measuring the inter-radicular distance and the thickness of mandibular cortical bone.
Asunto(s)
Tornillos Óseos , Cefalometría/métodos , Arco Dental/anatomía & histología , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Diente Premolar , Densidad Ósea , Cadáver , Diente Canino , Arco Dental/diagnóstico por imagen , Precisión de la Medición Dimensional , Fijación Interna de Fracturas/instrumentación , Humanos , Fracturas Mandibulares/cirugía , Persona de Mediana Edad , Estadísticas no Paramétricas , Tomografía Computarizada por Rayos X , Raíz del DienteRESUMEN
PURPOSE: The aim of this study was to determine the thickness of the parietal bone in bone graft donor sites and to study the relationship between parietal bone thickness and gender or cephalic index. MATERIALS AND METHODS: We studied 300 parietal bones from 150 human skulls (84 male and 66 female) from individuals aged 18 to 60 years at the time of death. On each parietal bone, 9 areas were drawn by use of reference anatomic landmarks (bregma, lambda, asterion, and pterion), and bone thickness was determined in the areas adjoining the sagittal suture--superior-anterior (Sa), superior-medial (Sm), and superior-posterior (Sp). RESULTS: Mean thickness measurements ranged from 2.30 to 11.25 mm in the Sa area, from 3.08 to 13.32 mm in the Sm area, and from 2.88 to 12.26 in the Sp area. Smaller mean measurements were observed in the Sa area, with the smallest mean thickness being found in brachycephalic female specimens. The largest mean thickness was also found in female specimens in the Sm area. Statistically significant differences between genders were found only in the Sa area in dolichocephalic and mesocephalic specimens. CONCLUSION: Although the best bone graft donor site surgically is different in individuals of different genders and with different cephalic indexes, our findings suggest that harvesting from the anterosuperior area of the parietal bone should not be performed.
Asunto(s)
Cefalometría/métodos , Hueso Parietal/anatomía & histología , Sitio Donante de Trasplante/anatomía & histología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Puntos Anatómicos de Referencia/anatomía & histología , Trasplante Óseo , Suturas Craneales/anatomía & histología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores Sexuales , Recolección de Tejidos y Órganos/métodos , Trasplante Autólogo , Adulto JovenRESUMEN
PURPOSE: The aim of this study was to determine by computed tomography (CT) the interalveolar distance on mandible relative to the canine, first and second pre-molar, and the thickness of the cortical bone in the same region. METHODS: A hundred adult cadaveric dentate human hemi-mandibles were examined. A point (P) above the upper margin of the mental foramen was determined, the height at which monocortical screws are inserted to place miniplate according to the technique to treat mandibular fracture. Then, points A, B and C at the same height as point P, referring to the dental units namely canine, first and second pre-molars were marked to determine the CT cut level to measure cortical bone thickness and the interalveolar distance. RESULTS: The figures showed no statistically significant difference between the sides. The thickness of the vestibular cortical bone was less than 3.0 mm in 96% of the samples. In 91% of the samples the interalveolar distance between canine, first and second pre-molars was greater than 2 mm, a potentially safe condition to insert 2.0-mm diameter monocortical screws at the study points. CONCLUSIONS: The individual actual anatomy of the region where screws are to be inserted above the mental foramen is important to perform the technique safely. We believe that the minimal cortical thickness to obtain sufficient screw anchorage should be studied in order to determine the actually safe shortest screw length. It is important to minimize the risk of tooth root damage or nerve injury and the amount of titanium in the human tissues.