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RESUMEN Introducción: estudios recientes indican que la cresta infracigomática es un sitio favorable para la colocación de mini implantes, sin embargo es importante conocer sus dimensiones anatómicas para colocarlos en una posición segura y lograr buena estabilidad. Objetivo: determinar el área, en diferentes zonas de la cresta infracigomática, que son utilizadas para la colocación de miniimplantes. Materiales y métodos: estudio descriptivo, observacional y transversal de 60 casos, con previo tratamiento de Ortodoncia y que reunieron los criterios de inclusión. Se utilizaron archivos radiográficos y de tomografías con tecnología cone-beam. Se realizó la estadística descriptiva y pruebas ANOVA, t de Student y método de comparación de Tukey para relacionar las variables. Resultados: la zona de mayor área de hueso se encontró a nivel de la cúspide mesiovestibular del segundo molar (30.2+12.1mm2). La clase esqueletal II presentó mayor área (33.6+11.2mm2). Se encontraron diferencias estadísticamente significativas al relacionar las variables área y zona, así como área y clase esqueletal, pero no hubo significancia estadística al relacionar el área con el sexo. Conclusiones. a nivel de la segunda molar superior es la referencia ideal para la colocación de mini implantes, en la cresta infracigomática, ya que esta tiene mayor área. Los casos Clase II presentan también un área mayor. El sexo no fue determinante (AU).
ABSTRACT Introduction: recent studies indicate that the infrazygomatic crest is a favorable site for the placement of miniscrew (mini implante), however it is important to know its anatomical dimensions to place them in a secure position and to obtain good stability. Objective: to determine the area in different sites of the infrazygomatic crest that is used for the placement of mini-implants. Materials and methods: descriptive, observational and cross-sectional study of 60 cases, with previous orthodontic treatment, that fulfilled the inclusion criteria. Radiographic and tomographic files with cone-beam technology were used. Descriptive statistics, ANOVA and t-Student tests, and Tukey's comparison method were used to relate the variables. Results: The zone with the largest area was found at the level of the second molar in the mesiovestibular cusp (30.2 + 12.1 mm2). Skeletal class II showed the largest area (33.6 + 11.2mm2). Statistically significant differences were found when relating the area and site variables as well as area and skeletal class, but there was no statistical significance in relating the area to sex. Conclusions: the level of the upper second molar is the ideal reference for the placement of mini-implants in the infrazygomatic crest since it has a larger area. Class II cases also have a larger area. Sex was not determinant (AU).
Subject(s)
Humans , Stomatognathic System/anatomy & histology , Dental Implants , Alveolar Process/anatomy & histology , Orthodontics , Tomography, X-Ray Computed , Epidemiology, Descriptive , Cross-Sectional Studies , Observational Studies as Topic , MexicoABSTRACT
Objective@#To investigate the soft and hard tissue morphology in the infrazygomatic crest zone by observing the cone-beam computed tomography (CBCT) scans in patients with mini-implants.@*Methods@#CBCT scans of 43 patients performed from January 2014 to December 2016 in the Department of Stomatology, Beijing Friendship Hospital, Capital Medical University, with 84 existing mini-implants in the infrazygomatic crest region were collected. The bone thickness and cortical bone thickness were measured in the palatal and buccal side of the mini-implant. The maxillary sinus membrane thickness, sinus septa, reverse fold, and the sinus opening angle were also determined and analyzed in the maxillary posterior region.@*Results@#The bone thicknesses in the buccal and palatal side of the existing mini-implant were 2.5 (1.5, 3.2) and 5.2 (4.0, 6.4) mm, respectively. However, the corresponding cortical bone thicknesses were only 2.1 (1.3, 2.8) and 1.5 (1.0, 1.9) mm, respectively. The prevalences of the septa and the reverse fold were 33% (28/84) and 45% (38/84), respectively. The sinus opening angle was the largest in the mid-coronal plane of the maxillary first molar (71.6°±15.6°). In the coronal plane located at 10 mm mesially, the angle was the smallest (46.1°±18.0°), and in this area, 20% (16/82) of the angle was less than 30°.@*Conclusions@#The outer cortical plate of the infrazygomatic crest along with the cortical plate of sinus floor could be related to the initial stability of mini-implant anchorage. The anatomic variation such as the reverse fold indicated thorough consideration of insertion depth and angle to avoid unexpected sinus injury.
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Objective To adopt the cone beam computed tomography(CBCT) to analyze the bone thickness of infrazygomatic crest with different vertical skeletal facial types in teenagers.Methods Sixty teenagers of skeletal class were collected,including each 20 cases of high angle,average angle and low angle.The CBCT scanning data of oral maxillofacial region were collected.The bone thickness at different coronary slices in buccal side of infrazygomatic crest region at 13,15,17 mm above the maxillary occlusal plane was measured.The measured data were analyzed statistically.Results The bone thickness of infrazygomatic crest was gradually thinned from down to up,and the difference was statistically significant(P＜0.05);the bone thickness(except 3 points at 13 mm from maxillary plane) at each measured point in the high,average and low angle groups showed the change trend of low angle ＞average angle＞high angle,the difference was not statistically significant(P＞0.05).Conclusion In teenagers,the bone thickness of infrazygomatic crest in skeletal class Ⅱ is gradually thinned from cranial direction and rearward,the high angle is thinnest and the low angle is thickest.
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Objective:To compare 2 position implant-supported molar distalization systems in clinical application.Methods:25 pa-tients with Class II and mild to moderate crowding dentition were included,18 females and 7 males,aged 15 to 29 years old(22.58 on average ).All the patients were treated with non-extraction method by distalizing the upper molar with micro-implant anchorage.In ex-perimental group(n =12)the micro-implants were inserted on infrazygomatic crest above the maxillary first molar mesial buccal root. In control group(n =13)the micro-implants were inserted on buccal alveolar bone between maxillary second premolar and maxillary first molar.In both groups micro-implants were inserted to distalize the maxillary molars.The displacement patterns of maxillary inci-sors and molars were measured and compared.Results:Successful primary micro-implant placement was obtained in 87.5%(21 /24) of the implantation in control group and 100%(26 /26)in experimental group.The distal movement(mm)of the molars in control and experiment group was 2.29 ±0.96 and 2.91 ±0.96 respectively(P >0.05).Experimental group showed significant intrusive displace-ment of the molars.Horizontal incisor displacement in experimental group was more than that in control group.Conclusion:Micro-im-plant inserted in infrazygomatic crest may facilitate intrusion and distalization of the maxillary molar and incisor.