Cortical and cancellous bone in mandibular symphysis: implications in osteosynthesis and osteotomy / Hueso cortical y esponjoso en sínfisis mandibular: implicancias en osteotomía y osteosíntesis

The aim of this study was to quantify the presence of cortical and cancellous bone in the mandibular symphysis. A descriptive study was conducted using cone beam computed tomography where skeletal class I and class III subjects were included, defined according to characteristics detected on dental, clinical and dental occlusion x-rays. From the 3D reconstruction, sections were used in relation to the axial axis of the teeth of the anterior sector; the amount of buccal cortical, cortical, lingual, inferior cortical and cancellous bone as well as symphysis height were determined. The measurements were taken using routine methods and analyzed with ANOVA and Tukey's HSD test with p <0.05 for statistical significance. 20 skeletal class I subjects aged 23 years (± 4.5) and 20 class III subjects aged 22 years (± 5.2) were included. Symphysis height was significantly greater in skeletal class III subjects, exceeding by 0.8 mm the height of class I subjects; the buccal cortical bone presented on average 2 mm less at different dental levels, whereas the lingual cortical and inferior basal bones were significantly larger than the buccal cortical bone. The cancellous and cortical bones did not present any significant differences between the two groups (p=0.093). The buccal and basilar cortical bone is smaller than lingual cortical bone.

El objetivo fue determinar la presencia de hueso cortical y esponjoso en sínfisis mandibular. Se realizó un estudio descriptivo en tomografías computadorizadas cone beam donde se analizaron sujetos clase I y clase III esqueletal definidos según características dentales, clínicas y radiográficas de oclusión dental y características radiográficas. Desde la reconstrucción 3D se utilizaron cortes en relación al eje axial de los dientes del sector anterior; en ellos se determinó la cantidad de hueso cortical bucal, cortical, lingual, cortical inferior, hueso esponjoso y altura de sínfisis. Las mediciones fueron realizadas con métodos de rutina y fueron analizados con la prueba ANOVA y HDS Turkey considerando un valor de p <0.05 para considerar significancia estadística. 20 sujetos clase I esqueletal con 23 años (+ 4.5) y 20 sujetos clase III esqueletal con edad de 23 años (+ 4.5) fueron incluidos. La altura de sínfisis fue significativamente mayor en sujetos de clase III esqueletal, superando por 0.8 mm la altura de sujetos clase I; el hueso cortical bucal presento en promedio menor de 2 mm en diferentes niveles dentarios, mientras que la cortical lingual y basal inferior fueron significativamente mayor que la cortical bucal. El hueso esponjoso y hueso cortical no presentó diferencias significativas entre ambos grupos (p=0.093). La cortical bucal y basilar son menores que el hueso cortical lingual.

Management of mandibular symphysis fracture associated with superolateral dislocation of the mandibular condyle: 10 case report / 实用口腔医学杂志

Mandibular symphysis fracture combined with anteromedial dislocated condyle fracture is commom in clinical,but mandibular symphysis fracture associated with superolateral dislocation of the mandibular condyle is rare,which is often misdiagnosed or completely over-looked.Malpractice can lead to ankylosis and other sequelae.This article reviews 10 patients with mandibular symphysis fracture associated with superolateral dislocation of the mandibular condyle,discusses the causative mechanism,diagnostic features and clinical management according to literature data.

Assessment of the mandibular symphysis of Caucasian Brazilian adults with well-balanced faces and normal occlusion: the influence of gender and facial type

OBJECTIVE: This study aimed to establish cephalometric reference values for mandibular symphysis in adults. Dentoalveolar, skeletal and soft tissue variables were measured considering the influence of gender and facial type. METHODS: The sample consisted of sixty cephalometric radiographs of white Brazilian adult patients, with a mean age of 27 years and 6 months, who had not undergone orthodontic treatment and who presented well-balanced faces and normal occlusion. The sample was standardized according to gender (30 males and 30 females) and facial type (20 were dolichofacial, 20 mesofacial and 20 brachyfacial). RESULTS: The results showed that male and female symphyses are similar, except for symphyseal height, which was greater in males. In terms of facial type, the dolichofacial group presented narrower symphysis in dentoalveolar and basal areas, with a more accentuated lingual dentoalveolar inclination. CONCLUSION: The brachyfacial group showed broader symphysis in the dentoalveolar and basal areas and a greater buccal dentoalveolar inclination. The projection of the chin was 6.67 mm below the subnasal vertical line and there was no significant difference between the genders or facial types.

A Case Report of Complications During Mandibular Transverse Symphysis Widening

Distraction osteogenesis on mandible symphysis widening with a bone-borne type distractor

Clinical study of mandible symphysis widening

Mandibular symphyseal distraction osteogenesis is an alternative approach for correcting mandibular transverse deficiencies and dental crowding. The traditional approaches for these are extraction of teeth and arch expansion with traditional orthodontic treatment. Also extractions are usually unavoidable in patients with severe crowding. The purpose of this study is to evaluate the effect of mandibular symphyseal distraction osteogenesis by use of tooth-borne expansion appliance. All of 12 patients had been performed distraction osteogenesis. The surgical procedures were accomplished under local anesthesia and intravenous sedation in an ambulatory surgical setting using a routine distraction protocol. The latency period was 5 days or 7 days after symphyseal osteotomies. The rate and rhyth is a intermittent, 0.75mm or 1.0 mm per day and stabilized for 6, 8 weeks after distraction. The time of orthodontic tooth movement after distraction was variable from 2 weeks to 8 weeks (mean 3 weeks). All patients had been evaluated with study casts, plain periapical films, panorama radiograms before and after surgery. Mandibular symphyseal distraction osteogenesis increased mandibular arch width and corrected dental crowding, with paralleling tooth-borne movement, without proclination of the mandibular incisors.

A study on the morphological changes of lower incisor and symphysis during surgical-orthodontic treatment in skeletal class III malocclusion / 대한치과교정학회지

The purpose of this study was to evaluate the morphological changes of alveolar bone and mandibular symphysis of lower incisor by presurgical orthodontic treatment and orthognathic surgery in skeletal class III malocclusion. The sample consisted of 30 adult class III malocclusion patients who have received bilateral sagittal split mandibular osteotomy. Lateral cephalograms were taken before treatment, after presurgical orthodontic treatment and 3 months after orthognathic surgery. Skeletal and symphyseal measurements were compared and the relationships between them were analysed. The results were as follow: 1. The labial and lingual alveolar bone height in presurgical and postsurgical group were decreased than that of pretreatment group. 2. The vertical measurements of the craniofacial skeleton showed reverse correlationship with anteroposterior width of basal alveolar bone, but IMPA showed correlationship(p<0.01). 3. The craniofacial skeleton and the change of symphyseal measurements(symphyseal length, symphyseal width) showed no correlationship. 4. The labial alveolar bone height showed correlationship with lingual alveolar bone height(p<0.001), and negative correlationship with lingual alveolar crestal width(p<0.01). Labial and lingual alveolar crestal width has negative correlationship (p<0.05). Mandibular symphyseal length and width has positive correlationship(p<0.01). 5. IMPA, LISA showed negative correlationship with labiolingual alveolar bone height and lingual alveolar width and positive correlationship with labial alveolar base bone width.

Quality and Morphology on cortico-cancellous bone in Korean mandibular symphysis area / 대한치주과학회지

In performing implant procedures in the anterior portion of the maxilla, many difficulties exist because of anatomical reasons, such as the proximity of the nasal floor, lateral extension of the incisive canal, and labial concavity. On the other hand, in the posterior region of the maxilla, there is often insufficient recipient bone between the maxillary sinus and alveolar ridge due to alveolar ridge resorption and pneumatization of the maxillary sinus. In order to perform implants in such regions, ridge augmentation procedures such as onlay bone graft, guided bone regeneration, and maxillary sinus grafting are performed. In studies of Caucasians, use of autograft from mandibular symphysis has been reported to be highly successful in maxillary sinus grafting. However, in a clinical study of Koreans, autograft of mandibular symphysis has been reported to have significantly low success rate. It has been hypothesized that this is because of insufficient cancellous bone due to thick cortical bone. In order to test this hypothesis, bone quality and morphology of Koreans can be compared with those of Caucasians. In this study, the bone density and morphology of the cortical bone and cancellous bone in the mandibular symphysis of 35 Korean cadavers were evaluated. The following results were obtained: 1. In terms of bone density, type I, type II, and type III consisted of 1.4%(3/213), 72.3%(154/213), and 26.3%(56/213) of the cross-sectioned specimens, respectively. In general, the bone density tended to change from type II to type III, as cross-sectioned specimens were evaluated from the midline to the canine. Type IV wasn't observed in this study. 2. The distance between the root apex and the lower border of the cancellous bone was 18.34mm-20.59mm. Considering that the bone has to be cut 5mm below the root apex during the procedure, autografts with about 15mm of vertical thickness can be obtained. 3. The thickness of cortical bone on the labial side increased from the root apex to the lower border of the mandible. The average values ranged from 1.43mm to 2.36mm. 4. The labio-lingual thickness of cancellous bone ranged from 3.43mm to 6.51mm. The thickness tended to increase from the apex to the lower border of the mandible and decrease around the lower border of cancellous bone. From the above results, the anatomic factors of the mandibular symphysis (bone density, thickness, quantity and length of the cortical bone and cancellous bone) didn't show any difference from Caucasians, and it cannot be viewed as the cause of failure in autografts in the maxillary sinus for implants.

A study of morphoiogy of mandibular symphysis and location of lower incisor under the influence of the craniofacial skeleton in skeletal Class III malocclusion / 대한치과교정학회지

The purpose of this study was to evaluate the morphology of mandibular symphysis and location of lower incisor under the influence of the craniofacial skeleton in skeletal Class III malocclusion. The sample consisted of 132 adults who, have severe Class III malocclusion(prognathism group, 33 males and 33 females), and who have normal occlusion(normal group, 33 males and 33 females). They had not received any orthodontic treatment or orthognathic surgery. The, lateral cephalograms were evaluated. The results were as follows: 1. Prognathism group were larger than normal group in comparison of facial skeleton (p0.05). 4. The probability by regression test between vertical measurements(angle SN-Mn, angle FMA, angle Pal-Mn, angle LFH) and symphysis measurements(LiACBW, LiABBW, SW, angle LISA) were very high (p<0.001).

The relationship between the morphology of mandibular symphysis and the craniofacial morphology in class lll malocclusion / 대한치과교정학회지

By studying the relationship between the morphology of mandibular symphysis and craniofacial morphology in class III malocclusion, this study aims at deciding whether the morphogy of mandibular symphysis can be used as a predictor on the growth of mandible. The materials used for this study were the cephalometric radiographs of male class III malocclusion. The subjected age groups were 10-12(G1 group) and 20 and above(G2 group); 50 were selected from each group. Each group was again divided, according to the ratio of symphysis, into Large(L), Average(A), and Small(S). The results of this study were summarized as follows: 1. In average the ratio of symphysis, G2 group showed significantly bigger than G1 group(P0.05). 3. In both G1 and G2 groups, there was not distinct difference in the antero-posterior positions among L, A, S subgroups. 4. L and A subgroups showed significantly larger than S subgroup in lower gonial angle and chin angle in G1 group (P<0.05) 5. In the measurements on the vertical relation of the face, anterior total face height(ATFH) and anterior lower face height(ALFH) of L subgroup were significantly larger than that of S subgroup in G1 group(P<0.05) and also mandible showed a tendency to grow downward vertically. 6. In the measurements on the tooth position and inclination, L subgroup showed as compared with S subgroup a tendency of extrusion of maxillary and mandibular teeth in G1 group, but G2 group showed such tendency only in mandibular teeth. 7. In the measurements on the abnormal growth prediction by Schulhof, in G1, there was no significant difference among L, A, S sugroups. 8. In the correlative analysis of the ratio of symphysis and other measurements, G1 group showed significant correlationships in chin angle, PP/MP angle, ANS-Me and other, while G2 group showed the same only in MP-LIT and MP-LMMC(P<0.05, P<0.01). In summarizing the above, in the G1 group, consisting of young males, no difference was noted in horizontal relation between L and S subgroups; in vertical relation, L subgroup showed a stronger tendency of downward growth of mandible than S subgroup. In adult male G2 group, however, no distinct morphological difference of craniofacial complex by the ratio of symphysis.

The relationship between the morphology of mandibular symphysis and the craniofacial morphology in Class III malocclusion / 대한치과교정학회지

By studying the relationship between the morphology of mandibular symphysis and craniofacial morphology in class III malocclusion, this study aims at deciding whether the morphogy of mandibular symphysis can be used as a predictor on the growth of mandible. The materials used for this study were the cephalometric radiographs of male class III malocclusion. The subjected age groups were 10-12(G1 group) and 20 and above(G2 group); 50 were selected from each group. Each group was again divided, according to the ratio of symphysis, into Large(L), Average(A), and Small(S). The results of this study were summarized as follows: 1. In average the ratio of symphysis, G2 group showed significantly bigger than G1 group(P0.05). 3. In both G1 and G2 groups, there was not distinct difference in the antero-posterior positions among L, A, S subgroups. 4. L and A subgroups showed significantly larger than S subgroup in lower gonial angle and chin angle in G1 group (P<0.05) 5. In the measurements on the vertical relation of the face, anterior total face height(ATFH) and anterior lower face height(ALFH) of L subgroup were significantly larger than that of S subgroup in G1 group(P<0.05) and also mandible showed a tendency to grow downward vertically. 6. In the measurements on the tooth position and inclination, L subgroup showed as compared with S subgroup a tendency of extrusion of maxillary and mandibular teeth in G1 group, but G2 group showed such tendency only in mandibular teeth. 7. In the measurements on the abnormal growth prediction by Schulhof, in G1, there was no significant difference among L, A, S sugroups. 8. In the correlative analysis of the ratio of symphysis and other measurements, G1 group showed significant correlationships in chin angle, PP/MP angle, ANS-Me and other, while G2 group showed the same only in MP-LIT and MP-LMMC(P<0.05, P<0.01). In summarizing the above, in the G1 group, consisting of young males, no difference was noted in horizontal relation between L and S subgroups; in vertical relation, L subgroup showed a stronger tendency of downward growth of mandible than S subgroup. In adult male G2 group, however, no distinct morphological difference of craniofacial complex by the ratio of symphysis.