Is Using a Ring External Fixator in the Treatment of Congenital Pseudarthrosis of the Tibia Associated With Better Results or Using a Locking Plate?

BACKGROUND: Congenital pseudarthrosis of the tibia (CPT) is a rare disease. CPT is often unilateral and occurs between the middle and distal third of the tibia. Concurrent involvement of the fibula is present in more than half of cases. histologic studies indicate the presence of fibrous hamartoma tissue and a sick periosteum, which leads to recalcitrant bone fracture and, eventually, pseudoarthrosis. Although there are various surgical techniques, we intend to compare the 2 methods of external fixation versus internal plating. METHODS: Demographic data were collected from 26 patients with frank pseudoarthrosis. After exclusion criteria, patients were compared in groups A (12 patients) and B (11 patients). Resection of hamartoma and sclerotic bone, intramedullary rodding and autologous bone, and periosteal grafting were performed for all patients. In group A, we used a ring external fixator for compression and rotational stability, but in group B, a locking plate was used for these purposes. RESULTS: Plating takes less time to use during surgery. In group A, the primary bony union was obtained in 67% of patients, while in group B, 82% of patients had a primary union. Meanwhile, the average time till the final union in group A was 6 months, while in group B, this time was 3.5 months. Positive union mass was obtained in 58% of the patients in group A and 82% of group B. In addition, plating prevented ankle valgus deformity in group B. CONCLUSIONS: Permanent intramedullary rodding is a surgical requirement for correction of deformity and refracture prevention, but additional stability can be achieved with the use of a ring external fixator or internal plate. Cross union and positive union mass are 2 important factors in the treatment of pseudoarthrosis; these results are achieved to a greater extent and in a shorter period of time using the plate. LEVEL OF EVIDENCE: level IV - case series.

Sex Determination Using Human Sphenoid Sinus in a Northeast Iranian Population: A Discriminant Function Analysis.

Statement of the Problem: Sex determination, using skeletal remains, is of paramount importance in forensic studies. The skull accounts for the most sexual dimorphism after the pelvis. Recent studies have shown that paranasal sinuses are valuable in sex determination and considering the location of the sphenoid sinus, the risk of traumatic injuries to this structure is low. Purpose: The present study aimed to evaluate the morphology of the sphenoid sinus and determine the validity of sphenoid sinus volume (SSV) in sex determination using cone beam computed tomography (CBCT) images. Materials and Method: In this cross-sectional retrospective study, CBCT images of 469 Iranian patients (186 male and 283 female), aged 24-45 years, were selected. The morphology of the sphenoid sinus was recorded. 3D Slicer software (4.10.0) was used to assess SSVs in coronal and axial planes. For data analysis, t-test, chi-square test, and discriminant function analysis (DFA) were performed using predictive analytics software (ver. 18.0). Results: The most common morphology of the sphenoid sinus in both genders was the sellar type (50.5%). SSV was significantly larger in males than in females (p< 0.001). DFA showed that the capability of SSV in sex identification was 86.0% and 92.9% in males and females, respectively. Conclusion: The findings of this study suggest that SSV is a reliable variable in gender discrimination in a northeast Iranian population. However, since the morphology of the sphenoid sinus and sex were independent of each other, the morphology of the sphenoid sinus is not a suitable indicator for sex determination.

Bone Regeneration Effect of Nanochitosan with or without Temporally Controlled Release of Dexamethasone.

INTRODUCTION: Chitosan is a cationic biopolymer, and its modification as a nanoparticle as well as loading a corticosteroid on it may enhance its bone regenerative effect. The aim of this study was to investigate the bone regenerative effect of nanochitosan with or without dexamethasone. METHODS: Under general anesthesia, 4 cavities were created in the calvarium of 18 rabbits and filled with nanochitosan, nanochitosan with a temporally controlled release of dexamethasone (nanochitosan + dexamethasone), an autograft, or left unfilled (control). The defects were then covered with a collagen membrane. The rabbits were randomly divided into 2 groups and were sacrificed at 6 or 12 weeks after surgery. The new bone type, osteogenesis pattern, foreign body reaction, and the type and severity of the inflammatory response were evaluated histologically. The amount of new bone was determined using histomorphometry and cone-beam computed tomographic imaging. One-way analysis of variance with repeated measures was performed to compare results between the groups at each interval. A t test and chi-square test were also conducted to analyze changes in variables between the 2 intervals. RESULTS: Nanochitosan and the combination of nanochitosan and dexamethasone significantly increased the combination of woven and lamellar bone (P = .007). No sample showed a foreign body reaction or any acute or severe inflammation. Chronic inflammation was significantly decreased in number (P = .002) and severity (P = .003) over time. There was no significant difference between the extent and pattern of osteogenesis among the 4 groups, as evaluated by histomorphometry and cone-beam computed tomographic imaging at each interval. CONCLUSION: Nanochitosan and nanochitosan + dexamethasone were comparable with the gold standard of autograft regarding the type and severity of inflammation as well as the level and pattern of osteogenesis; yet, they induced more woven and lamellar bone.

Prognosis of Congenital Pseudarthrosis of the Tibia: Effect of Site of Tibial Pseudarthrososis and Fibular Involvement.

BACKGROUND: Congenital pseudarthrosis of the tibia is a rare condition that has long been one of the most challenging concerns in pediatric orthopedic surgery. When the fracture occurs, a recalcitrant nonunion is expected. This is why successful treatment means maintaining a long-term union. In this study, we aimed to assess the therapeutic outcomes for the middle and distal third fractures of the tibia and to explore whether the treatment of concurrent fibular pseudoarthrosis affects the outcome. METHODS: We studied 12 patients with congenital pseudarthrosis of the tibia (Crawford type 4) from 2014 to 2019. A combination approach including intramedullary rod, Ilizarov apparatus, corticocancellous bone graft, and periosteal graft was used. In the initial surgery, we did not fix the ankle and subtalar joints. RESULTS: As a result, the union was achieved in 67% of the cases after the index surgery. All of the cases with primary nonunion were related to the concurrent fibular and distal third tibial pseudarthrosis. In addition, ignoring the treatment of fibular pseudarthrosis in the index surgery led to ankle valgus deformity both in the middle and in the distal third tibial pseudarthrosis. We finally achieved a 100% union rate in all cases, with no subsequent refracture. CONCLUSIONS: Surgery at an early age was associated with favorable results and minimized deformity. In concurrent fibular and distal third tibial pseudarthrosis, it is recommended to transfix the ankle and subtalar joints to create a cross-union with fibula so that the intense union can be confidently obtained with more cross-section to prevent ankle valgus deformity. LEVEL OF EVIDENCE: Level IV-case series.

The efficacy of five different techniques in identifying C-shaped canals in mandibular molars.

Information regarding the canal anatomy especially in complex cases such as C-shaped canals is essential for a successful treatment. In this study, five different methods for identification of C-shaped canal configuration were compared. 108 extracted mandibular molars with fused roots were studied. Radiographic evaluation was carried out using periapical radiography and CBCT. After access cavity preparation, all specimens were evaluated by direct visual examination and then under dental operating microscope. Finally, the actual anatomy of each sample was determined by preparing horizontal cross sections of the roots (1 mm thick) and examining them under stereomicroscope as the gold standard. Among the techniques used, high-resolution CBCT manifested the highest accuracy, whereas periapical radiography had the lowest. All approaches can be useful in reaching a correct diagnosis. CBCT, especially the low-resolution modality, is an effective technique in the diagnosis of C-shaped anatomy.

Relationship between Anatomical Variations of Sinonasal Area and Maxillary Sinus Pneumatization.

INTRODUCTION: Maxillary sinuses are among the largest paranasal sinuses with various shapes and volumes. The dimensions and volumes of maxillary sinuses play an important role in the surgical treatment plan. The higher levels of pneumatization of alveolar bone lead to the increase of odontogenic sinusitis which cause problems in dental implantation. Therefore, this study aimed to evaluate the relationship between maxillary sinus volume and pneumatization and anatomical factors. MATERIALS AND METHODS: In this cross-sectional study, computed tomography (CT) images of the healthy maxillary sinuses of 199 adult patients were reviewed. Amira software was used for the measurement of sinus volume. Sinus pneumatization of the alveolar bone in coronal CT scan images in the posterior teeth areas was measured. Moreover, anatomical variations of the sinonasal region, such as nasal septal deviation, and size of the ostium were measured and recorded. The Kolmogorov-Smirnov test, the t-test, and the Pearson's and Spearman's correlation coefficients were applied for data analysis. RESULTS: According to the obtained results, the mean value of the maxillary sinus volume and the alveolar bone pneumatization were 15.54 mm3 and 3.54 mm, respectively. The mean value of the maxillary sinus volume was statistically higher among males than females (P<0.001). The prevalence of nasal septal deviation, concha bullosa, and maxillary sinus septa were 14.6%, 14.6% and 6% respectively. There were no association between anatomical factors, including the nasal septal deviation, the size of the ostium, concha bullosa, and maxillary sinus septa and maxillary sinus volume and pneumatization. P-value less than 0.05 was statistically significant. CONCLUSION: No correlation was observed between the anatomical variations of the sinonasal region and maxillary sinus volume and pneumatization.

Evaluation of condylar positions in patients with temporomandibular disorders: A cone-beam computed tomographic study.

PURPOSE: This study was performed to compare the condylar position in patients with temporomandibular joint disorders (TMDs) and a normal group by using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: In the TMD group, 25 patients (5 men and 20 women) were randomly selected among the ones suffering from TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The control group consisted of 25 patients (8 men and 17 women) with normal temporomandibular joints (TMJs) who were referred to the radiology department in order to undergo CBCT scanning for implant treatment in the posterior maxilla. Linear measurements from the superior, anterior, and posterior joint spaces between the condyle and glenoid fossa were made through defined landmarks in the sagittal view. The inclination of articular eminence was also determined. RESULTS: The mean anterior joint space was 2.3 mm in the normal group and 2.8 mm in the TMD group, respectively. The results showed that there was a significant correlation between the superior and posterior joint spaces in both the normal and TMD groups, but it was only in the TMD group that the correlation coefficient among the dimensions of anterior and superior spaces was significant. There was a significant correlation between the inclination of articular eminence and the size of the superior and posterior spaces in the normal group. CONCLUSION: The average dimension of the anterior joint space was different between the two groups. CBCT could be considered a useful diagnostic imaging modality for TMD patients.

Relationship of the Gonial Angle and Inferior Alveolar Canal Course Using Cone Beam Computed Tomography.

OBJECTIVES: Accurate localization of the inferior alveolar canal (IAC) is extremely important in some dental treatments. Anatomical variation of the canal means that it can be difficult to locate. The purpose of this study was to assess the relationship of the gonial angle (GA) size and IAC position using cone beam computed tomography (CBCT). MATERIALS AND METHODS: In this in vitro study, 61 dry adult human hemi-mandibles were used. The CBCT scans were taken of all samples and GA was measured on all CBCT scans. The samples were divided into two groups of low angle (≤125°) and high angle (>125°). The canal dimensions, length and course were evaluated. On the sagittal view, the IAC path was classified as type A, B or C. On the axial view, canal course was defined as A1 or A2 according to the mental foramen angle. RESULTS: The average GA size was 121.8±7.05° at the right side and 123.8±6.32° at the left side. On the sagittal view, there was a significant correlation between the GA size and the canal course (P=0.04). In the high-angle group, type A was dominant; whereas in the low-angle group, type B was more common. On the axial view of IAC course, type A1 was more common (73.43%). CONCLUSION: The results showed that GA size was associated with IAC course. In cases with a larger GA, the canal runs in a more straightforward path, and at the same level as the mental foramen.

Evaluation of c-kit protein (CD117) expression in common salivary gland neoplasms.

BACKGROUND: Adenoid cystic carcinoma (AdCC) is a malignant salivary gland neoplasm with poor long-term prognosis. Differentiating between AdCC and other salivary gland neoplasms can be a diagnostic challenge, particularly in examining tissues obtained from small incisional biopsies. AIM: The aim of this study was to evaluate c-kit expression in four common benign and malignant salivary gland neoplasms. MATERIALS AND METHODS: Immunohistochemical techniques were used to analyze the level of c-kit expression in normal salivary gland (n = 10) and four different types of salivary gland tumors: Pleomorphic adenoma (PA) (n = 17), AdCC (n = 9), polymorphous low-grade adenocarcinoma (PLGA) (n = 4) and mucoepidermoid carcinoma (MEC) (n = 6). Samples were immunostained using monoclonal antibody against c-kit. RESULTS: The immunoreactivity for c-kit was found in all cases of AdCC, PLGA and MEC and majority of PAs. Positive reactivity was observed in more than 50% of the tumor cells of AdCC and less than 50% in PLGA. PA did not show strong immunostaining and c-kit was predominantly localized to the cell membrane. Furthermore, the difference in the expression of c-kit between the benign and malignant neoplasms was not statistically significant. CONCLUSIONS: CD117 expression itself cannot be used as a marker in differential diagnosis of salivary gland neoplasms. However, the percentage of the CD117 immunoreactive cells and the staining intensities appeared to be important factors in distinguishing AdCC from PLGA and PA.

Hand skeletal maturity and its correlation with mandibular dental development.

OBJECTIVES: Assessment of pubertal status and pubertal growth spurt in orthodontic patients has a considerable impact on the diagnosis, treatment plan and the outcome of orthodontic treatments. Hand-wrist radiography is routinely used to evaluate skeletal development. Some studies have shown that there is an association between bone development and different stages of dental calcification; therefore, the stages of dental calcification can be used as the first tool for diagnosis, in case there is an association. This study was performed with the aim to evaluate the association between the phases of dental development and the stages of skeletal maturity. STUDY DESIGN: In this study, a total of 52 patients (26 males and 26 females), referring to Mashhad School of Dentistry for orthodontic treatment, were evaluated; the subjects were within the age range of 9-14 years. Hand-wrist radiographic evaluation of skeletal maturation was performed using Fishman method. Also, the Demirjian method was used to identify the stages of dental calcification by panoramic radiographs. Independent t-test and Spearman correlation coefficient were used for data analyses. RESULTS: The mean age of males and females was 11.05 ± 1.05 and 10.62 ± 1.12 years, respectively (p=0.156). The Spearman correlation coefficients between skeletal maturity indicators (SMIs) and developmental stages of mandibular left and right canines and second molars were significant in males only (p<0.05). Also, correlation coefficients were significant between adductor sesamoid ossification and mandibular right and left canines developmental stages in males (p<0.05). CONCLUSIONS: Findings of this study showed that the correlation between dental developmental stages and skeletal maturity only were significant in males; thus, different skeletal maturity patterns in males and females might be perceptible. Key words:Skeletal maturation, hand-wrist radiography, panoramic radiography.

Cone-beam computed tomography evaluation of maxillary first and second molars in Iranian population: a morphological study.

INTRODUCTION: The aim of this in vitro study was to identify the root and canal morphology of maxillary first and second molars in Iranian population by taking and analyzing cone-beam computed tomography (CBCT) scans. METHODS AND MATERIALS: Extracted maxillary first (n=125) and second (n=125) molars were collected from native Iranians and scanned by using a CBCT scanner. The number of roots and configuration of root canal system were classified according to Vertucci's classification. RESULTS: Two (1.6%) maxillary first and two (1.6%) maxillary second molars had four roots. Prevalence of root fusion was 2.4% and 8.8% in maxillary first and second molars, respectively. The most common canal morphology in the mesiobuccal roots of three-rooted first and second molars was type I (46.4% and 80.8%, respectively), followed by type VI (17.6%) in first molars. The predominant morphology of distobuccal and palatal roots in first and second molars was type I. Additional canal types were also identified. CONCLUSION: Profound knowledge of anatomic variations is necessary prior to cleaning and obturation of the root canal system. The most common discovered root morphology was three separate roots in both tooth types. The greatest variation in canal anatomy was discovered in the MB canals of both the first and second molars.

Expression of E-cadherin and matrix metalloproteinase-9 in oral squamous cell carcinoma and histologically negative surgical margins and association with clinicopathological parameters.

Minimal residual cancer cells may not be detected in surgical margins of oral squamous cell carcinoma (OSCC) with routine histological examination. Using molecular markers at surgical margins can be helpful. We attempted to evaluate the MMP-9 and E-cadherin expression in OSCC samples and tumor-free surgical margins and association with clinicopathological factors. We examined E-cadherin and MMP-9 expression in 58 OSCCs including 19 grade I, 21 grade II and 18 grade III with histological tumor-free surgical margins by immunohistochemistry. Specimens were also divided in two groups: 19 samples as an early and 39 as an advanced stage. For E-cadherin in OSCCs and surgical margins, significant difference was observed between poor and moderate tumor differentiation. Different stages of OSCC demonstrated significant differences with higher expression in early stage tumors. For surgical margins, 82.1% of advanced and 84.2% of early stage samples demonstrated immunoreactivity. Both OSCC samples and surgical margins demonstrated significant differences for MMP-9 between stages with higher immunoreactivity in advanced stage, whereas there were not differences between different grades in surgical margins. E-cadherin and MMP-9 expression at histologically negative surgical margins shows the significance of these markers for prognostic values in OSCC patients with E-cadherin being the preferred predictor.

Residual dentin thickness of bifurcated maxillary premolars following two post space preparation methods.

INTRODUCTION: The aim of this in vitro study was to compare the effect of Gates-Glidden and Peeso reamer drills on residual dentin thickness during post space preparation in order to discover which method has minimum root structure damage. MATERIALS AND METHODS: Thirty extracted human maxillary premolars with bifurcations at root middle were horizontally cut 15 mm coronal to the apical end after root canal treatment. The samples were scannedby Cone Beam Computed Tomography (CBCT) before and after preparing the post space. Residual dentin thicknesses were measured at 4-, 6-, and 8-mm levels from the apex. Data were analyzed using repeated measured ANOVA. RESULTS: Endodontic therapy and post space preparations removed more dentin within the bifurcation of both roots compared to outer dentin. The difference in residual dentin thickness was highly significant regarding stage (before and after post space preparation) in all levels and stage × device in coronal and middle levels (P<.05). This in vitro study emphasizes the minimal dentin width in the buccal root of maxillary premolars, especially near the bifurcation. CONCLUSION: Lack of adequate residual dentin thickness after post space preparation implies that the use of posts in maxillary first premolars should be limited. When mandatory, it is recommended that post space be prepared with Gates-Glidden drill in the palatal root of maxillary first premolars and use of Peeso reamer be avoided.

Dental age assessment of young Iranian adults using third molars: A multivariate regression study.

BACKGROUND: In recent years, a noticeable increase in forensic age estimations of living individuals has been observed. Radiologic assessment of the mineralisation stage of third molars is of particular importance, with regard to the relevant age group. To attain a referral database and regression equations for dental age estimation of unaccompanied minors in an Iranian population was the goal of this study. Moreover, determination was made concerning the probability of an individual being over the age of 18 in case of full third molar(s) development. MATERIALS AND METHODS: Using the scoring system of Gleiser and Hunt, modified by Köhler, an investigation of a cross-sectional sample of 1274 orthopantomograms of 885 females and 389 males aged between 15 and 22 years was carried out. Using kappa statistics, intra-observer reliability was tested. With Spearman correlation coefficient, correlation between the scores of all four wisdom teeth, was evaluated. We also carried out the Wilcoxon signed-rank test on asymmetry and calculated the regression formulae. RESULTS: A strong intra-observer agreement was displayed by the kappa value. No significant difference (p-value for upper and lower jaws were 0.07 and 0.59, respectively) was discovered by Wilcoxon signed-rank test for left and right asymmetry. The developmental stage of upper right and upper left third molars yielded the greatest correlation coefficient. The probability of an individual being over the age of 18 is 95.6% for males and 100.0% for females in case four fully developed third molars are present. Taking into consideration gender, location and number of wisdom teeth, regression formulae were arrived at. CONCLUSION: Use of population-specific standards is recommended as a means of improving the accuracy of forensic age estimates based on third molars mineralisation. To obtain more exact regression formulae, wider age range studies are recommended.

Clinicoradiological findings of benign osteopetrosis: report of two new cases.

Osteopetrosis represents a heterogeneous group of rare, hereditary bone dysplasias that share the hallmark of increased bone density caused by osteoclast dysfunction. It can manifest through a spectrum of symptoms and severity, from neonatal onset with life-threatening complications ("malignant" autosomal recessive osteopetrosis) to two more benign conditions with the incidental radiographic findings, principally affecting adults (autosomal dominant osteopetrosis type I and type II). We report 2 new cases of autosomal dominant osteopetrosis type II. Both subjects were short in stature. Multiple healed fractures of long bones, diminished marrow spaces and hypoplastic maxillary sinuses were remarkable findings. To our knowledge they are the first reported cases of autosomal dominant type II of this disease in Iran.

Periapical Status and Quality of Root canal Fillings and Coronal Restorations in Iranian Population.

INTRODUCTION: This cross-sectional survey determined the dental prevalence of apical periodontitis (AP) in selected Iranian population, and evaluated the influence of the quality of root canal treatment (RCT) and their coronal restorations (CR) on the periapical status. MATERIALS AND METHODS: A total of 1064 panoramic radiographies were evaluated by two observers during 2009. The quality of RCT i.e. length/density of root fillings and CR in addition to periapical status of endodontically treated teeth were recorded. Their interrelationship was analyzed by Chi-squared, logistic regression and Spearman's rho statistics. Hosmer and Lemeshow tests were used for assessing fitness of logistic regression model and one sample k-s test was used for evaluating of normality of the data. RESULTS: Our results showed that 527 teeth (52%) of the endodontically treated teeth presented with AP radiographically. The percentages of teeth which fulfilled the criteria of an acceptable RCT or CR radiographically were 42.3 and 62.5 respectively. Incidence of AP among teeth with acceptable RCT (29.1%) was significantly lower than those suffering from unacceptable RCT (68.8%) (P<0.001). Moreover, adequate CR demonstrated a significantly better periapical status (58.6%) compared to teeth with inadequate CR (30.3%) (P<0.001). The incidence of AP ranged from 25.6% (good qualities) to 79.5% (bad qualities) (P<0.001). Cases with both unacceptable RCT/CR were 11 times more likely to have AP than cases with acceptable RCT/CR. The quality of RCT and CR were found to impact the periapical health of endodontically treated teeth. CONCLUSION: There are a significant high number of technically unacceptable endodontic and restorative treatments in Iran; therefore considerable efforts are needed to improve the standards of endodontic and restorative treatments.