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Avicenna Journal of Dental Research - Volume:9 Issue: 2, Jun 2017

Avicenna Journal of Dental Research
Volume:9 Issue: 2, Jun 2017

  • تاریخ انتشار: 1396/02/18
  • تعداد عناوین: 8
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  • Shapour Yaripoor, Pejman Janbaz * Page 1
    Context: Using a reliable fixation method after ramus sagittal split osteotomy in order to reduce the chances of treatment relapse and condyle changes is still one of the most noteworthy issues discussed among maxillofacial surgeons. In this study, the results of the up-to-date papers were collected, which identify the effects of the fixation method on the post-operative results, to give the reader a comprehensive view of the new concepts.
    Evidence Acquisition: The most frequent mandibular surgeries, setbacks, and advancements via the bilateral sagittal split osteotomy technique were used for a literature search due to the abundance of related articles. Consequently, the following keywords were applied: sagittal split ramus osteotomy, orthognathic surgery, rigid fixation, non-rigid fixation, postoperative relapse, and postoperative stability.
    Results
    The articles were classified according to the surgery procedure: mandibular advancement surgery or mandibular setback surgery. The relapse pattern can be divided into two categories: an early relapse, which is strongly related to the surgery procedure, and a late relapse, which can be attributed to the physiologic changes, such as a growth map. The contributing factors can be considered to be the following: a change in ramus in inclination, the mandibular plane, and the fixation type.
    Conclusions
    Using rigid fixation techniques after bilateral sagittal split ramus osteotomy will optimize the stability, but this stability is not influenced by the method of this rigid fixation; although the most commonly suggested technique, bicortical screws, is in the inverted-L position
    Keywords: Sagittal Split Ramus Osteotomy, Jaw Fixation Technique, Stability
  • Safa Hinnara, Imad Barngkgei *, Jihad Abo Nassar Page 2
    Background
    Numerous studies showed that the convergence angle (CA) of prepared teeth for fixed prosthodontics in the clinical practice is greater than the recommended values.
    Objectives
    This cross-sectional study aimed to compare the total occlusal convergence (TOC) angles of metal ceramic fixed prosthodontics among dental students [final-year undergraduate (UG) and Master Prosthodontics (MS) students] and general practitioners (GP) in their private clinics with the recommended value (≤ 12 degrees).
    Methods
    The buccolingual (BL) and mesiodistal (MD) TOC of 114, 90, and 111 stone dies referred to UG, MS, and GP, respectively, were measured. These dies included incisors, premolars, and molars. One sample Wilcoxon signed rank test, Mann-Whitney U test, Kruskal-Wallis, and Fisher exact test were used for statistical analysis.
    Results
    Mean values of TOC for UG were 27.8 degrees BL and 20.9 degrees MD, whereas they were 30.6 degrees BL and 18.2 degrees MD for MS. GP had TOC of 35.5 degrees BL and 24 degrees MD. GP had significantly higher TOC values than the other groups (0.001 > P value ≤ 0.007). In each group, TOC did not differ when calculated for partial fixed prosthodontic and single crown abutments (0.117 ≤ P value ≤ 0.797). Molars in general had the highest TOC values. Only 0.9%, 3.3%, and 0.9% of UG, MS, and GP, respectively, respected the TOC ≤ 12 degrees.
    Conclusions
    In all the groups, tooth preparations were inconsistent with the recommended TOC values, even among specialists in fixed prosthodontics. These results support the existing literature that the recommended values were rarely achieved and may require reconsideration.
    Clinical Significance: Clinically, the CA values of prepared teeth for fixed prosthodontics exceed the recommended values in most cases, not only among general practitioners, but also among students in academic institutes. Thus, the effects of teeth preparations with CA greater than the recommended values on the longevity of the prosthodontics should be further investigated.
    Keywords: Convergence Angle, Crowns, Partial Fixed Prosthodontic, Taper, Total Occlusal Convergence
  • Massoumeh Khoshhal, Fariborz Vafaee, Oranous Moradi, Neda Rastegarfard*, Erfan Abbasi, Shahram Sharifi Page 3
    Background
    The minimum standard treatment plan for the reconstruction of an edentulous mandible, according to York, is an overdenture supported by two implants.
    Objectives
    The aims of this study were to evaluate and compare the clinical outcomes and peri-implant marginal bone loss around implants in patients treated with mandibular overdentures supported by 1, 2, 3, 4, and 5 implants.
    Materials And Methods
    A total of 25 patients with a mean age of 62.7 years old, who were treated with implant supported mandibular overdentures at Hamedan’s faculty of dentistry, were enrolled in this cross-sectional study. Among these patients, 6 had overdentures supported by one implant, 9 had overdentures supported by two implants, 2 had overdentures supported by three implants, 5 had overdentures supported by 4 implants, and 3 had overdentures supported by 5 implants. The clinical and radiographic parameters around the implants were assessed, including: probing depth, width of keratinized gingiva, bleeding on probing, peri-implant inflammation, calculus formation, implant mobility, adverse events, and radiographic signs of peri-implant bone loss (distance between the implant shoulder and the level of the mesial and distal proximal bone). The ANOVA and the Fisher’s Exact test were used to evaluate the significant differences among the groups.
    Results
    None of the implants had loosened and no adverse events were seen around the implants. Additionally, the clinical variables did not show significant correlation with the number of implants. Overall, the bone resorption showed an inverse and significant relationship with the number of implants (P = 0.001).
    Conclusions
    With mandibular overdentures supported by 1, 2, 3, 4, and 5 implants, favorable clinical outcomes can be achieved. However, when increasing the number of implants, marginal bone loss decreases. For example, the patients with five implants showed less marginal bone loss than those with a lesser number of implants.
    Keywords: Bleeding on Probing, Calculus, Keratinized Gingiva, Mandibular Overdenture, Probing Depth
  • Fatemeh Ezoddini, Soghra Yassaei, Sahar Ghanea * Page 4
    Background
    This study was performed to assess the diagnostic accuracy of panoramic radiography in determining the position of impacted permanent maxillary canines.
    Methods
    This was a diagnostic study to define how accurate panoramic radiography is in determining the position of impacted permanent maxillary canines. In panoramic radiographs of 33 patients (with 44 total impacted maxillary canines), α and β angulation, magnification and superimposition were assessed. The long axis of the impacted canine to the occlusal line was named α angle. The long axis of the impacted canine to the vertebral line was named β angle. The real position of the teeth was determined by CBCT. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of panoramic radiography were calculated. Kappa test was used to assess the agreement between panoramic radiography and CBCT. Roc curves were used to define cut-off point values.
    Results
    α angulation showed 84.3% of palatal impacted maxillary canines and 41.6% of buccal teeth in their real position. β angulation showed these positions in 81.8% and 87.5% of cases, magnification in 37.5% and 58.3% of cases and superimposition in 53.6% and 100% of cases. The degree of agreement between CBCT and α angulation, β angulation, magnification, and superimposition was 0.275, 0.526, 0.03 and 0.224, respectively. Cut-off point values for α angulation, β angulation and CII were 65 degrees, 63 degrees and 1.11, respectively.
    Conclusions
    Among different methods, β angulation showed the highest accuracy in the localization of impacted maxillary canines. α angulation and superimposition ranked second and third in terms of accuracy. Magnification had the least accuracy.
    Keywords: Canine Tooth, Panoramic, Radiography
  • Shahin Setoudehmaram, Sara Masoumi *, Shahla Momeni Danaei, Barbod Zamiri Page 5
    Background
    The hyoid bone position may change in class III patients following different surgical procedures, including mandibular setback, maxillary advancement, and bimaxillary advancement.
    Objectives
    The aim of this study was to conduct a detailed cephalometric evaluation of changes in the hyoid bone position following treatment of class III skeletal deformities via different surgical procedures (ie, mandibular setback, maxillary advancement, and bimaxillary advancement).
    Methods
    A total of 120 consecutive patients, who were diagnosed with skeletal class III deformities, were recruited in this study. All the patients were adults with complete growth and cephalograms taken at 1 month before operation (T1) and 1 to 9 months postoperation (T2) in the natural head position. The patients were divided into 3 groups according to the type of surgery: group 1, bimaxillary advancement; group 2, mandibular setback; and group 3, maxillary advancement. The hyoid bone position was evaluated at both T1 and T2 in each group. The results were compared using paired t test and one-way ANOVA.
    Results
    The hyoid bone position showed no significant changes in groups 1 and 3 (P
    Conclusions
    The hyoid bone position changed only after mandibular setback surgery; the bone was displaced downward and backward following mandibular retraction. On the other hand, neither bimaxillary nor maxillary advancement could change the hyoid bone position.
    Keywords: Orthognathic Surgery, Class III Deformity, Hyoid Bone Position
  • Fatemeh Ahmadi-Motamayel *, Ali Reza Soltanian, Ali Basir Page 6
    Background
    Pattern of tooth eruption (TE) may vary in different communities and may be affected by many factors. It also may cause nutritional problems in infants and anxiety in parents. The current study aimed at investigating the relationship between birth weight and other factors contributing to the time of the first TE.
    Methods
    The current study employed the multistage sampling method to select 126 infants admitted to the health centers of Hamadan, Iran. Health records of infants were listed and relevant information was collected using a questionnaire and interviewing the parents. The tooth emergence was considered as TE in the current study. Finally, the recruited infants were examined for the eruption of the first primary tooth. Descriptive, linear, and the curve regression tests were used with SPSS version 16.
    Results
    Despite the significant differences in weight and height between male and female infants, no significant relationship was observed between time of the first primary TE and most of the studied variables. Height, feeding with formula, family income, and mother's age had inverse effects on TE time. Infants who were fed with synthetic formula milk had earlier TE. Eruption sign and infant height had the most effects on delayed TE.
    Conclusions
    No significant relationship was observed between the eruption time of the first primary tooth and the studied variables. Nevertheless, there was a significant association between the infant’s height and time of the first primary TE.
    Keywords: Tooth Eruption, Deciduous Tooth, Infant
  • Farzaneh Ostovarrad, Faezeh Yousefi, Sepideh Falah-Kooshki, Atena Karimi * Page 7
    Introduction
    Fibrous dysplasia is a developmental bone disease that is characterized by replacement of normal bone with fibrous tissue.
    Case Presentation
    A 58-year-old man came to the Oral and Maxillofacial Radiology Department, Hamadan College of Dentistry, with swelling on the left side of the maxilla. The lesion was diagnosed to be fibrous dysplasia of the maxilla with involvement of the maxillary sinus, based on the radiographic and histopathologic features.
    Conclusions
    Some radiographic features, such as a ground glass appearance and reduction in antrum size while keeping the original shape, are characterizations of fibrous dysplasia.
    Keywords: Fibrous Dysplasia, Maxilla, Radiographic Feature
  • Mohammad Esmaelizadeh, Abbas Shokri, Zakieyeh Donyavi, Farzaneh Ostovarrad, Hadi Ranjzad, Shiva Yarmohammadi *, Frideh Vahidnia Page 8
    Introduction
    A dentigerous cyst is the most commonly developed cyst of the jaw. It is most frequently associated with impacted canines and mandibular third molars. Bilateral dentigerous cysts are rare and are generally associated with developmental syndromes or systemic diseases.
    Case Presentation
    We report on an eight-year-old boy who presented with a complaint of bilateral malposed first mandibular molars. There was no complaint of pain and no swelling. An intraoral examination revealed buccal tipping of both the right and left first mandibular molars with slight swelling. The overlying mucosa was completely normal and there was no tenderness on palpation. This unusual case occurrence associated with the crowns of the bilateral impacted lower second molars. There are no cases reported with bilateral dentigerous cyst involving mandibular second molars. The clinical and radiographic findings, especially the cone beam computed tomography (CBCT) views, were suggestive of dentigerous cysts.
    Conclusions
    After the surgical removal of the cysts, the specimens were sent for histopathological evaluation. A microscopic examination suggested infected dentigerous cysts.
    Keywords: Cone Beam Computed Tomography, Bilateral Dentigerous Cyst, Nonsyndromic