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1.
J Prosthet Dent ; 125(1): 138.e1-138.e8, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33393474

RESUMEN

STATEMENT OF PROBLEM: Mini implants (<3 mm in diameter) are being used as an alternative to standard implants for implant-retained mandibular overdentures; however, they may exhibit higher stresses at the crestal level. PURPOSE: The purpose of this finite element analysis study was to evaluate the biomechanical behavior (stress distribution pattern) in the mandibular overdenture, mucosa, bone, and implants when retained with 2 standard implants or 2 mini implants under unilateral or bilateral loading conditions. MATERIAL AND METHODS: A patient with edentulous mandible and his denture was scanned with cone beam computed tomography (CBCT), and a 3D mandibular model was created in the Mimics software program by using the CBCT digital imaging and communications in medicine (DICOM) images. The model was transferred to the 3Matics software program to form a 2-mm-thick mucosal layer and to assemble the denture DICOM file. A 12-mm-long standard implant (Ø3.5 mm) and a mini dental implant (Ø2.5 mm) along with the LOCATOR male attachments (height 4 mm) were designed by using the SOLIDWORKS software program. Two standard or 2 mini implants in the canine region were embedded separately in the 3D assembled model. The base of the mandible was fixed, and vertical compressive loads of 100 N were applied unilaterally and bilaterally in the first molar region. The material properties for acrylic resin (denture), titanium (implants), mucosa (tissue), and bone (mandible) were allocated. Maximum von Mises stress and strain values were obtained and analyzed. RESULTS: Maximum stresses of 9.78 MPa (bilaterally) and 11.98 MPa (unilaterally) were observed in 2 mini implants as compared with 3.12 MPa (bilaterally) and 3.81 MPa (unilaterally) in 2 standard implants. The stress values in the mandible were observed to be almost double the mini implants as compared with the standard implants. The stresses in the denture were in the range of 3.21 MPa and 3.83 MPa and in the mucosa of 0.68 MPa and 0.7 MPa for 2 implants under unilateral and bilateral loading conditions. The strain values shown similar trends with both implant types under bilateral and unilateral loading. CONCLUSIONS: Two mini implants generated an average of 68.15% more stress than standard implants. The 2 standard implant-retained overdenture showed less stress concentration in and around implants than mini implant-retained overdentures.


Asunto(s)
Implantes Dentales , Prótesis de Recubrimiento , Prótesis Dental de Soporte Implantado , Análisis del Estrés Dental , Retención de Dentadura , Análisis de Elementos Finitos , Humanos , Mandíbula/diagnóstico por imagen , Estándares de Referencia , Estrés Mecánico
2.
Swiss Dent J ; 131(1): 10-28, 2021 01 11.
Artículo en Inglés | MEDLINE | ID: mdl-33325209

RESUMEN

The mandibular canal is a prominent anatomical structure and it is of great clinical importance since it contains the inferior alveolar nerve. The clinician is advised to proceed cautiously in the vicinity of the mandibular canal to avoid any damage to its neurovascular content. Based on observations in dry mandibles, in panoramic radiographs, and recently in three-dimensional radiography, various anatomical variations of the mandibular canals have been described. One such variant is the so-called bifid mandibular canal (BMC). Embryologically, multiple canals develop and subsequently fuse to form a single mandibular canal; however, occasionally fusion fails or is incomplete resulting in one or multiple BMCs. Clinically relevant issues with regard to the BMCs include hemorrhagic or neurological disorders following damage to these aberrant canals. This literature review presents morphological and quantitative data about BMCs from studies using three-dimensional radiography, i.e. CT and/or CBCT. The reported frequencies of BMCs per patient ranged from 9.8 - 66.5% and per mandibular side from 7.7 - 46.5%. Gender, age or side predilection is currently inconclusive with regard to the occurrence of BMCs. Various types of BMCs have been described in the literature, such as retromolar, dental, forward, or buccolingual canals. BMCs may originate from the mandibular canal along its entire course, but bifurcation appears to be more frequent in the posterior compared to the anterior canal portions. Mean BMC length was reported to range from 10.2 - 16.9 mm, and mean BMC diameter from 0.9 - 2.3 mm. In conclusion, the presence of a BMC must be taken into consideration for treatment planning and anesthetic, endodontic, or surgical interventions in the mandible.


Asunto(s)
Tomografía Computarizada de Haz Cónico , Mandíbula , Humanos , Mandíbula/diagnóstico por imagen , Nervio Mandibular/diagnóstico por imagen , Radiografía Panorámica
3.
Clin Nucl Med ; 46(1): e11-e12, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33156043

RESUMEN

McCune-Albright syndrome is a rare condition consisting of triad of fibrous dysplasia, hyperfunctioning endocrinopathy, and café au lait macules of skin. A 31-year-old man was diagnosed with fibrous dysplasia 18 years before presenting with pathologic fracture. No workup for polyostotic fibrous dysplasia was performed at that time. He now presented with left facial swelling and skeletal features of acromegaly. MRI revealed a 15-cm enhancing tumor diagnosed histopathologically as high-grade osteosarcoma. Tc-methylene diphosphonate bone scintigraphy revealed decreased uptake at the tumor site contrary to the usual finding of avid uptake by the neoplastic bone forming tumor.


Asunto(s)
Neoplasias Óseas/complicaciones , Neoplasias Óseas/diagnóstico por imagen , Displasia Fibrosa Poliostótica/complicaciones , Mandíbula/diagnóstico por imagen , Osteosarcoma/complicaciones , Osteosarcoma/diagnóstico por imagen , Acromegalia/complicaciones , Adulto , Humanos , Imagen por Resonancia Magnética , Masculino
4.
Dentomaxillofac Radiol ; 50(1): 20200108, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-32706991

RESUMEN

OBJECTIVE: The aim was to compare dental and skeletal indices in panoramic radiography between patients undergoing haemodialysis, peritoneal dialysis and age- and sex-matched control group. METHODS: In this comparative cross-sectional study, quantitative Indices including Antegonial Index (AI), Mental Index (MI), Panoramic Mandibular Index (PMI) and qualitative indices including Mandibular Cortical Index (MCI) and Trabecular Pattern (TP) were evaluated in panoramic images of 32 haemodialysis patients, 14 patients under peritoneal dialysis and 52 healthy individuals. The images were also investigated for pulp canal calcification, pulp stones, soft tissue calcification, changes in or loss of lamina dura, radiolucencies associated with brown tumour and ridge resorption. The indices were compared between the three groups and were investigated for association with the patients' blood test parameters and their diseases causing chronic renal failure (CRF). Intraobserver agreement for the 2-week interval of assessment was calculated for the indices. RESULTS: MI (p = 0.574) and PMI (p = 0.100) were not significantly different, but AI (p = 0.01), MCI (p < 0.001) and TP (p = 0.002) were significantly different between the two case groups and the control group. The prevalence of pulp calcification (p = 0.03) and ridge resorption (p = 0.005) was higher in the haemodialysis group. Soft tissue calcification (p = 0.85) and lamina dura changes (p = 0.9) showed no significant difference. Brown tumours were observed in only one case in the haemodialysis group. CONCLUSIONS: AI, MCI and TP showed a reduction in mineral density of the cortical and trabecular bone in CRF patients and more severely in patients under haemodialysis than those under peritoneal dialysis.


Asunto(s)
Densidad Ósea , Diálisis Peritoneal , Estudios Transversales , Humanos , Mandíbula/diagnóstico por imagen , Diálisis Peritoneal/efectos adversos , Radiografía Panorámica , Diálisis Renal
5.
BMJ Case Rep ; 13(12)2020 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-33370934

RESUMEN

A 33-year-old male patient reported to us with the history of assault. The patient was cooperative and oriented, with no sign of head injury. He was assaulted with an axe over the mandible. The patient is having posteroanterior view radiographs of the mandible suggesting isolated horizontal fracture of the anterior mandible. Under general anaesthesia, this unusual fracture was treated by open reduction and internal fixation with a three-dimensional plate and miniplates. The case was managed successfully without any postoperative complications.


Asunto(s)
Fijación Interna de Fracturas , Mandíbula , Fracturas Mandibulares , Reducción Abierta/métodos , Complicaciones Posoperatorias/prevención & control , Adulto , Placas Óseas , Fijación Interna de Fracturas/instrumentación , Fijación Interna de Fracturas/métodos , Humanos , Masculino , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Fracturas Mandibulares/diagnóstico , Fracturas Mandibulares/etiología , Fracturas Mandibulares/cirugía , Radiografía/métodos , Resultado del Tratamiento
6.
J Oral Sci ; 63(1): 83-86, 2020 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-33311011

RESUMEN

PURPOSE: Circadian rhythm is associated with the pathogenesis of systemic disease and bone mineral metabolism. This study aimed to radiographically evaluate morphological characteristics of the interalveolar septum in circadian rhythm deficient animals. METHODS: Heads of 10 brain and muscle arnt-like protein-1 (BMAL1)-knockout (KO) mice and 10 wild-type mice sacrificed at 36 weeks were imaged using micro-computed tomography. The mean depth from the cementoenamel junction to the alveolar ridge (virtual bone sounding: VBS) of the interalveolar septum between the first and second molars, and the bone mineral density (BMD) of the interalveolar septum and the mandibular inferior cortex region were calculated. Tooth diameter was also measured. RESULTS: The VBS of the interalveolar septum in the BMAL1-KO mice was significantly deeper than that in wild-type mice. The BMD in the BMAL1-KO mice was significantly lower than in the wild-type mice in both regions. No significant difference was observed in tooth diameter between BMAL1-KO and wild-type mice. CONCLUSION: These results suggest that low BMD in the interalveolar septum accelerates bone resorption in the interalveolar septum in BMAL1-KO mice.


Asunto(s)
Factores de Transcripción ARNTL , Mandíbula , Factores de Transcripción ARNTL/genética , Animales , Técnicas de Inactivación de Genes , Mandíbula/diagnóstico por imagen , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microtomografía por Rayos X
7.
J Clin Pediatr Dent ; 44(4): 274-282, 2020 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33167022

RESUMEN

OBJECTIVE: To investigate the cephalometric changes following anterior repositioning of the mandible for predicting the treatment effects in Class II adolescent patients. STUDY DESIGN: Lateral cephalograms of 28 patients (ANB > 4°) were taken in centric occlusion (CO) and edge-to-edge bite (EtoE) before orthodontic treatment. The patients were classified into two groups according to their mandibular plane angle [MPA; low MPA (LMPA) ≤ 28° and high MPA (HMPA) > 28°]. Cephalometric changes of hard and soft tissues were measured and analyzed with an x-y cranial base coordinate system. RESULTS: For CO to EtoE, there were no significant cephalometric changes between HMPA and LMPA, but the horizontal ratio of soft to hard tissue pogonion (H-Pog'/H-Pog) change was significantly greater with LMPA than with HMPA while the vertical ratio (V-Pog'/V-Pog) showed vice versa. For CO to EtoE, MPA showed significant correlations with H-Pog'/H-Pog and V-Pog'/V-Pog. Y-axis angle, V-Pog'/V-Pog and H-Pog'/H-Pog can be used as good tools to discriminate between HMPA and LMPA. CONCLUSION: Cephalometric findings for CO to EtoE may be useful in predicting the vertical and horizontal changes of hard and soft tissues with the treatment of growing adolescents having various vertical skeletal patterns of Class II malocclusion.


Asunto(s)
Reposicionamiento de Medicamentos , Maloclusión de Angle Clase II , Adolescente , Cefalometría , Estudios Transversales , Humanos , Maloclusión de Angle Clase II/diagnóstico por imagen , Maloclusión de Angle Clase II/terapia , Mandíbula/diagnóstico por imagen , Pronóstico
8.
Int J Periodontics Restorative Dent ; 40(6): e235-e240, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33151196

RESUMEN

This case report describes the rehabilitation of an extremely atrophic posterior mandible using 4-mm ultrashort implants and reports clinical and radiographic outcomes 7 years after loading. The patient refused to undergo any other treatment, from the removable prosthesis to the reconstructive surgery, and asked for a fixed, minimally invasive solution in the shortest possible time. The residual bone height above the alveolar nerve was an average of about 5 mm, so it was decided to treat the patient with four 4-mm ultrashort implants. Within the limitations of this case report, this procedure appears successful at 7 years after loading in this specific case and could reduce invasiveness, rehabilitative times, and costs. However, longer follow-ups on a large number of patients coming from randomized controlled clinical trials are necessary before making more reliable recommendations.


Asunto(s)
Pérdida de Hueso Alveolar , Aumento de la Cresta Alveolar , Implantes Dentales , Pérdida de Hueso Alveolar/cirugía , Implantación Dental Endoósea , Diseño de Prótesis Dental , Prótesis Dental de Soporte Implantado , Fracaso de la Restauración Dental , Estudios de Seguimiento , Humanos , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Resultado del Tratamiento
9.
Orthod Fr ; 91(1-2): 129-137, 2020 06 01.
Artículo en Francés | MEDLINE | ID: mdl-33146127

RESUMEN

When performed several times over the course of an orthodontic or surgical orthodontic treatment, three-dimensional (3D) imaging like CBCT or CT-Scans can be superimposed. The purpose of this article is to illustrate the implementation of voxel-based 3D superimpositions with a clinical case of mandibular distraction osteogenesis A 13-year old patient underwent a surgical orthodontic treatment with a « 3D ¼ mandibular distractor. He presented a bilateral atrophy of his mandibular condyles due to a staphylococcus aureus bacteremia at birth. 3D general and mandibular regional superimpositions were performed using CT-Scan and CBCT images acquired respectively before and after completion of the distraction osteogenesis. Two superimposition methods were used, one relying on commercially-available software and the other one relying on a series of « open-source ¼ softwares. Using commercially-available software, 3D superimpositions were automatically performed in a few minutes by a sparsely-trained operator. The method relying on « open-source ¼ software asked for more training and time. Results of the superimpositions were presented under various formats. Evaluation of 3D superimposition results is still challenging, as only a qualitative evaluation can be easily performed. In years to come, this interpretation should however become more straightforward for clinicians.


Asunto(s)
Osteogénesis por Distracción , Adolescente , Humanos , Imagenología Tridimensional , Masculino , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Programas Informáticos , Tomografía Computarizada por Rayos X
10.
J Clin Pediatr Dent ; 44(5): 356-365, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-33181848

RESUMEN

OBJECTIVE: The objective of this retrospective study was to investigate the relationship between mandibular symphysis bone density (BD) and mandibular growth direction in adolescent patients by facilitating the measurement of cortical and cancellous BDs at the mandibular symphysis using cone beam computed tomography (CBCT). STUDY DESIGN: 224 adolescent patients (98 males and 126 females) were categorized by sex, age, and mandibular growth direction. Cortical and cancellous BDs were measured along with a sagittal slice at multiple locations. RESULTS: Females exhibited higher cortical BD than males at menton (Me, P =0.002). Patients with a posterior growth direction exhibited a higher cortical BD than those with anterior and normal growth direction at Me (P <0.021, P <0.001, respectively), pogonion (Pog, P =0.037, P =0.037, respectively) and genion (Ge, P =0.007, P =0.008, respectively). Patients with a posterior growth direction exhibited a higher cortical BD than those with anterior growth direction at B point (P =0.009). CONCLUSIONS: Significant differences in BD were identified across anthropometric categories. These findings may be useful in determining mandibular growth direction in adolescents.


Asunto(s)
Densidad Ósea , Tomografía Computarizada de Haz Cónico Espiral , Adolescente , Tomografía Computarizada de Haz Cónico , Femenino , Humanos , Masculino , Mandíbula/diagnóstico por imagen , Estudios Retrospectivos
11.
J Oral Maxillofac Surg ; 78(11): 2099.e1-2099.e9, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-33131550

RESUMEN

PURPOSE: The use of nonvascular bone grafts for immediate mandibular reconstruction has remained a controversial topic. The purpose of the present study was to investigate the variables that might influence graft survival examining the outcomes from 30 years of experience. MATERIALS AND METHODS: We designed a retrospective cohort study to analyze the data from patients at a tertiary university medical center who had undergone segmental mandibular resection with immediate reconstruction with a nonvascularized free bone graft with or without adjuncts from 1989 to 2019. The predictor variables recorded included general demographic data, pathologic diagnosis, resection length, reconstruction modality, bone graft type, and inferior alveolar nerve procedures. The primary outcome variable was graft success, defined as bony union demonstrated on panoramic radiographs and mandibular stability demonstrated on clinical examination at 4 months postoperatively. Descriptive, bivariate, and linear regression models were computed. RESULTS: The sample included 47 subjects with a mean age of 43 ± 16 years; 51.1% were men. Of the 47 patients, 25 had a tissue diagnosis of benign tumor, most of which were ameloblastoma (n = 16) or ossifying fibroma (n = 6), and 22 had a tissue diagnosis of osteomyelitis or medication-related osteonecrosis of the jaw (MRONJ). The average resection size for all the patients was 6.9 ± 2.5 cm and was 6.1 ± 1.5 cm for those with a benign tumor and 7.8 ± 3.1 cm for those with osteomyelitis or MRONJ. The mean defect size of grafts that failed was 10.7 ± 3.5 cm and 6.5 ± 2.0 cm for those that succeeded (P ≤ .001). A linear regression model revealed that graft length correlated significantly with graft outcome (ß-coefficient, -0.548; 95% confidence interval, 0.905 to 1.542; P ≤ .001). CONCLUSIONS: The results of our study have shown that nonvascular bone grafts can be used to immediately reconstruct mandibular defects greater than 6 cm from benign pathologic lesions; however, larger grafts are more likely to fail.


Asunto(s)
Neoplasias Mandibulares , Reconstrucción Mandibular , Adulto , Trasplante Óseo , Femenino , Humanos , Masculino , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento
12.
Head Face Med ; 16(1): 31, 2020 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-33243266

RESUMEN

BACKGROUND: A new distraction osteogenesis assembly system comprising a fully customized CAD/CAM-based fixation unit and ready-made distraction unit was developed. The aim of this study was to introduce our new distraction system and to evaluate its accuracy level in a sampled mandibular distraction osteogenesis. METHODS: Our system consists of a fully customized CAD/CAM-based fixation plate unit with two plates for each moving and anchoring part, and a ready-made distraction unit with attachment slots for fixation plates. The experimental distractions were performed on 3D-printed mandibles for one control and two experimental groups (N = 10 for each group). All groups had reference bars on the chin region and teeth to measure distraction accuracy. The control group had the classical ready-made distraction system, and experimental groups 1 and 2 were fitted with our new distraction assembly using a different distractor-positioning guide design. All distracted experimental mandibles were scanned by CT imaging, then superimposed on a 3D simulation to get their discrepancy levels. RESULTS: The measured 3D distances between the reference landmarks of the surgical simulations and the experimental surgeries for the three groups were significantly different (p < 0.0001) by statistical analysis. The errors were greater in the control group (with a total average of 19.18 ± 3.73 mm in 3D distance between the simulated and actual reference points) than those in the two experimental groups (with an average of 3.68 ± 1.41 mm for group 1 and 3.07 ± 1.39 mm for group 2). The customized distraction assembly with 3D-printed bone plate units in group 1 and 2, however, did not show any significant differences between simulated and actual distances (p > 0.999). CONCLUSION: Our newly-developed distraction assembly system with CAD/CAM plate for the distraction osteogenesis of the mandible produced a greater level of accuracy than that of a conventional distraction device. The system appears to address existing shortcomings of conventional distraction devices, including inaccuracy in vector-controlled movement of the system. However, it also needs to be further developed to address the requirements and anatomical characteristics of specific regions.


Asunto(s)
Osteogénesis por Distracción , Placas Óseas , Diseño Asistido por Computadora , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Osteogénesis
13.
J Contemp Dent Pract ; 21(6): 666-672, 2020 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33025936

RESUMEN

AIM: The development of a class II malocclusion is usually related to a reduced oropharyngeal airway space. In order to prevent airway obstruction, functional appliances are commonly used for orthodontic therapy. The aim of the article is to verify if these appliances could positively influence oropharyngeal diameters preventing the onset of future respiratory disorders. MATERIALS AND METHODS: A group of 10 patients treated at the Dental Clinic of San Gerardo Hospital in Monza with mandibular activator was selected. Ten similar untreated class II subjects with retrognathic mandible were used as control group. The cephalometric tracings were made on lateral teleradiographs of the skull before and after the active therapy with functional devices for the treated group and before and after growth peak for the control one. Descriptive statistical analysis was calculated for all the cephalometric values in both study cases and control group using Excel worksheet. The data distribution was evaluated with Shapiro-Wilk test and the in-between group discrepancies were evaluated with Mann-Whitney U test. RESULTS: At T1 period, both case and control groups showed a class II pattern. At T2 period, the study group shows an improvement in bones relationship with reduced ANB angles and OVJ measurements. The control group otherwise did not show any important changes in maxillo-mandibular discrepancies. The airway size increased in either group in most cases. No significant differences between the treated and control groups were detected for airway size neither in the upper, middle, nor lower level at the T1-T2 interval. CONCLUSION: The upper airway values did not show any significant discrepancies between the two groups during the observation period. CLINICAL SIGNIFICANCE: Functional devices were effective in solving class II relationships, but there is no evidence of successful breathing disorders prevention by using mandibular activators, probably due to the stability of airway tissues reached in pubertal age in both groups.


Asunto(s)
Maloclusión de Angle Clase II , Faringe , Cefalometría , Humanos , Maloclusión de Angle Clase II/diagnóstico por imagen , Maloclusión de Angle Clase II/terapia , Mandíbula/diagnóstico por imagen , Estudios Retrospectivos
14.
Am J Orthod Dentofacial Orthop ; 158(6): 783-798.e20, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33077369

RESUMEN

INTRODUCTION: Safe zone maps are useful for the clinician to plan miniscrew insertion and possibly reduce radiation exposure. This study aimed to investigate the available evidence regarding the presence of sufficient interradicular space and adequate cortical bone thickness in patients with a complete permanent dentition, in the vestibular and palatal or lingual interradicular sites, mesial to the second molar. METHODS: PubMed, Scopus, Web of Science, Cochrane Library, and OpenGrey databases were searched up to January 2019 for observational studies involving patients with fully erupted second molars that investigated the amount of interradicular space and/or the cortical thickness of the alveolar processes using 3-dimensional data sets. A custom tool was prepared and used to assess the risk of bias in individual studies. A meta-analysis was performed when at least 4 different studies evaluated 1 identical parameter homogeneously. Publication bias was assessed with the Egger linear regression test. RESULTS: Twenty-seven observational articles were included in the qualitative synthesis. Only 11 articles were at low risk of bias. Fifteen articles were included in the meta-analysis. The results were graphically reported in "safe-zone" maps. CONCLUSIONS: In the maxilla, the most suitable insertion sites are those from mesial to the first molar to distal to the first premolar, and between the canine and the lateral incisor, all at 6 mm from the cementoenamel junction. In those areas, the cortical bone has adequate thickness, not requiring predrilling. In the mandible, the preferable vestibular interradicular spaces are those between first and second molars and between first and second premolars, both at 5 mm from the cementoenamel junction, and predrilling is suggested in these areas. TRIAL REGISTRATION NUMBER: PROSPERO CRD42016042081.


Asunto(s)
Tomografía Computarizada de Haz Cónico , Raíz del Diente , Hueso Cortical/diagnóstico por imagen , Humanos , Mandíbula/diagnóstico por imagen , Maxilar/diagnóstico por imagen , Raíz del Diente/diagnóstico por imagen
15.
Medicine (Baltimore) ; 99(43): e22778, 2020 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-33120788

RESUMEN

BACKGROUND: To analyze the sagittal positions of the mandibular prominence and maxillary central incisors in adult Chinese Han men to establish their aesthetic profile characteristics. METHODS: Seventy-four Chinese Han men aged 18 to 40 years underwent cone beam computed tomography for detecting the distances between Glabella and Subnasale, Subnasale and Menthon of soft tissue, Condyle and Gonion, Pogonion and Pogonion's Anterior Limit Line, Facial Axis point of maxillary central incisor and the Goal Anterior Limit Line as well as the angle of the Occlusal Plane. Dolphin Imaging and Photoshop software packages were used to generate silhouette profiles. Thirteen orthodontists assessed the silhouette profiles and assigned visual analog scale scores. Scores >70 were assigned to the aesthetic (group 1), scores of 60to 70 to the general (group 2), scores of 50 to 60 to the acceptable (group 3), and scores of <50 to the unaesthetic profile (group 4). RESULTS: A total of 15 men were assigned to group 1, 35 to group 2, 14 to group 3, and 10 to group 4. There were no significant differences in the variables examined between groups 1, 2, and 3, but comparing group 1 with group 4, Pogonion and Pogonion's Anterior Limit Line (1.16 ±â€Š2.61 mm vs -1.44 ±â€Š2.92 mm, P = .046) and Facial Axis-Goal Anterior Limit Line (-0.61 ±â€Š2.54 mm vs 1.70 ±â€Š2.62 mm, P = .038) there were significant differences. CONCLUSION: Compared with the unaesthetic profile group, the sagittal positions of the maxillary central incisors were slightly posterior, and the chin was slightly anterior in adult Chinese Han men with an aesthetic profile.


Asunto(s)
Grupos Étnicos , Incisivo/anatomía & histología , Incisivo/diagnóstico por imagen , Maxilar/anatomía & histología , Maxilar/diagnóstico por imagen , Adolescente , Adulto , Cefalometría/métodos , Mentón/anatomía & histología , Mentón/diagnóstico por imagen , China , Tomografía Computarizada de Haz Cónico/métodos , Humanos , Masculino , Mandíbula/anatomía & histología , Mandíbula/diagnóstico por imagen , Estudios Prospectivos , Valores de Referencia , Adulto Joven
16.
Medicine (Baltimore) ; 99(43): e22779, 2020 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-33120789

RESUMEN

This study aimed to measure temporomandibular joint (TMJ) with 3-dimensional (3D) reconstruction technique in Chinese northeast population, and to clarify the region for fixation and to provide morphological basis for the application of TMJ prosthesis in Chinese setting.Computed tomography (CT) scan and 3D reconstruction were performed with 132 individuals. Structural markers and measurements were further performed with a 3D model of the total TMJ, including the width, thickness and angle of zygomatic arch, the width and height of articular fossa, as well as the area, width, thickness and angle of mandible in the fixation region of the TMJ prosthesis. All the measured indicators values were compared between bilateral sides and gender groups.There was no statistical difference in the measured indicators between the left side and the right side (P > .05). However, certain parameters, including S, L5, L7, P4, and P5, were significantly different among males and females (P < .05).In this study, 3D CT image was used to obtain the measurement data of TMJ, which provided data support for the clinical application of TMJ prosthesis in Chinese population.


Asunto(s)
Imagenología Tridimensional/métodos , Mandíbula/diagnóstico por imagen , Articulación Temporomandibular/diagnóstico por imagen , Adulto , Anciano , Femenino , Humanos , Prótesis Articulares , Masculino , Mandíbula/cirugía , Reconstrucción Mandibular/métodos , Persona de Mediana Edad , Factores Sexuales , Articulación Temporomandibular/cirugía , Adulto Joven
17.
J Craniomaxillofac Surg ; 48(11): 1045-1051, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33012600

RESUMEN

PURPOSE: To evaluate the frequency of deep lingual concavities in the lower jaw, which can cause surgical complications while inserting dental implants. METHODS: Cross-sections of the mandible alveolar ridge at the edentulous sockets were obtained via cone-beam computed tomography. Measurements were carried out using the freeware 'IC Measure' and based on the basic definitions of a previous study. RESULTS: Most (767/826 = 93%) sockets had concavities of various degrees (30-90°), while 59 (7%) sockets had no concavity. However, the majority of the concavities (71%) were mild, with angles > 60°. The other 220 (26%) sockets had deeper concavities of <60°; among these, 12 (1%) had extremely deep concavities of <40°. CONCLUSIONS: Only a few cases have deep lingual concavities that pose a high risk for lingual plate perforation during dental implantation.


Asunto(s)
Implantes Dentales , Boca Edéntula , Tomografía Computarizada de Haz Cónico , Implantación Dental Endoósea/efectos adversos , Humanos , Mandíbula/diagnóstico por imagen , Mandíbula/cirugía , Lengua , Alveolo Dental
18.
Prog Orthod ; 21(1): 36, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-33000308

RESUMEN

OBJECTIVE: To compare the accuracy of complete-arch scans and quadrant scans obtained using a direct chairside intraoral scanner. MATERIAL AND METHODS: Intraoral scans were obtained from 20 adults without missing teeth except for the third molar. Maxillary and mandibular complete-arch scans were carried out, and 4 quadrant scans for each arch were performed to obtain right posterior, right anterior, left anterior, and left posterior quadrant scans. Complete-arch scans and quadrant scans were compared with corresponding model scans using best-fit surface-based registration. Shell/shell deviations were computed for complete-arch scans and quadrant scans and compared between the complete-arch scans and each quadrant scans. In addition, shell/shell deviations were calculated also for each individual tooth in complete-arch scans to evaluate factors which influence the accuracy of intraoral scans. RESULTS: Complete-arch scans showed relatively greater errors (0.09 ~ 0.10 mm) when compared to quadrant scans (0.05 ~ 0.06 mm). The errors were greater in the maxillary scans than in the mandibular scans. The evaluation of errors for each tooth showed that the errors were greater in posterior teeth than in anterior teeth. Comparing the right and left errors, the right side posterior teeth showed a more substantial variance than the left side in the mandibular scans. CONCLUSION: The scanning accuracy has a difference between complete-arch scanning and quadrant scanning, particularly in the posterior teeth. Careful consideration is needed to avoid scanning inaccuracy for maxillary or mandibular complete-arch, particularly in the posterior area because a complete-arch scan might have potential error than a quadrant scan.


Asunto(s)
Anodoncia , Mandíbula/diagnóstico por imagen , Adulto , Algoritmos , Humanos
19.
J Contemp Dent Pract ; 21(7): 756-759, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33020358

RESUMEN

AIM: The cervical vertebral maturation (CVM) method has proved to be effective to assess the adolescent growth peak in both body height and mandibular size. The aim of this study was to evaluate whether cone-beam computed tomography (CBCT) images can be used to detect the changes of cervical vertebral bone mineral density (BMD) distribution and whether these changes are associated with CVM changes and mandibular length. MATERIALS AND METHODS: Samples were collected from the patients of age group between 9 years and 15 years of both sexes, who reported to the Department of Orthodontics and Dentofacial Orthopedics, RajaRajeswari Dental College and Hospital, Bengaluru. All the measurements were done on constructed CBCT three-dimensional images. Gray levels, which are equivalent to the BMD, were obtained for C2 and C3 vertebrae at pretreatment (T1) and six months after starting the treatment (T2). The vertebral variables [mean, standard deviation (SD)], CVM stages, and mandibular length between T1 and T2 were compared. RESULTS: Significant changes in the examined variables were detected during the observation period. The BMD values showed a positive correlation with mandibular length increments. CONCLUSION: The CBCT is an effective tool to analyze the volumetric parameter of BMD in routine dentofacial orthopedics and the BMD distribution changed because of active bone remodeling during the maturation. CLINICAL SIGNIFICANCE: This study proves that CBCT imaging can provide additional information about the growth status of a patient above and beyond that obtained from two-dimensional cephalometric radiographs. CBCT is an effective tool to analyze the volumetric parameter of BMD in routine dentofacial orthopedics with better accuracy and minimum distortion.


Asunto(s)
Densidad Ósea , Vértebras Cervicales/diagnóstico por imagen , Adolescente , Cefalometría , Tomografía Computarizada de Haz Cónico , Femenino , Humanos , Masculino , Mandíbula/diagnóstico por imagen
20.
J Contemp Dent Pract ; 21(7): 765-768, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33020360

RESUMEN

AIM: The present study was conducted to evaluate the reliability of cone-beam computed tomography (CBCT) in dental asymmetry with skeletal midline deviation. MATERIALS AND METHODS: This study was conducted on 124 patients (males 52, females 72) who underwent orthodontic treatment. The CBCT scan was obtained with the Planmica machine. Three maxillofacial radiologists evaluated 10 landmarks and 12 distances on maxillary and mandibular arches on CBCT images in all patients. RESULTS: Interobserver mean difference at point 1 was 0.33; point 2, 0.34; point 3, 0.32; point 4, 0.58; point 5, 0.56; point 6, 0.44; point 7, 0.28; point 8, 0.22; point 9, 0.54; point 10, 0.21; point 11, 0.34; and point 12, 0.36. The discrepancy between intra- and interobserver was not considerable (p > 0.05). CONCLUSION: Cone-beam computed tomography is useful for diagnosis of skeletal asymmetry. CLINICAL SIGNIFICANCE: Cone-beam computed tomography is a reliable and reproducible tool for diagnosis of skeletal asymmetry for successful orthodontic treatment.


Asunto(s)
Tomografía Computarizada de Haz Cónico , Mandíbula/diagnóstico por imagen , Femenino , Humanos , Masculino , Maxilar/diagnóstico por imagen , Reproducibilidad de los Resultados
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