Stress Distributions Created by Short and Regular Implants Placed in the Anterior Maxilla at Different Angles: A Finite Element Analysis

Although short implants are seen as alternative treatments that require additional surgical techniques in posterior region, they can be applied to anterior maxilla and various studies are required on this subject. The purpose of this study was to examine and compare the peak von Mises stress distributions in the crown, implant and abutment by using finite element analysis (FEA). Besides, a comparison of the implant-abutment connection types in the short implant with the FEA method was established. A short implant (4 × 5 mm) with a taper-lock connection and a regular implant (4 × 9 mm) with a screw connection were used in maxillary central incisor tooth area. Three different titanium abutments with 0?, 15? and 25? angles were used for abutments. In addition, in order to determine whether the stress change in short implants is due to the length of the implant-abutment connection, a screw was designed for a short implant and it was also evaluated in the same three angles. A total of three groups and nine models were generated. 114.6N load was applied to the cingulum area of the crown at an angle of 135? to the long axis of the crowns. A torque load of 25 Ncm was applied to the regular and short implant screw. Von Mises stress distributions of implants, abutments and crowns were evaluated by using FEA. Increased angle in implants increased von Mises stress values of implant, abutment and crown. Screw connection was found higher at all angles in short implants. Close values were found at different angles in taper-lock short implant crowns. The length and the angle in the bone of implant with the type of implant-abutment connection results in the accumulated stress values. Clinical Implications Taper implant-abutment connection system was found to be more promising in terms of stress accumulation in crowns. Although the amount of stress on the abutment increased due to the length of the implant in short implants, taper implant-abutment connection system slightly reduced related to this increase.

Spindle Cell Carcinoma of the Maxilla: A Case Report of Rare Entity

Spindle cell carcinoma also known as sarcomatoid carcinoma is a rare highly aggressive tumor which is histologically different from squamous cell ca and mesenchymal cancers. Only hands full of cases have been reported in literature since 1957 and hence no proper treatment protocol has been devised yet. We present such a case of thirty-four-year-old female who presented with spindle cell carcinoma of the maxilla at our department and was treated with extensive surgery followed by chemotherapy and radiation therapy. Spindle cell carcinoma is generally associated with poor prognosis and hence literature supports use of post operative Chemo and Radiotherapy for better result and decrease chance of local recurrence.

Radiation-induced osteosarcoma of the maxilla and mandible after radiotherapy for nasopharyngeal carcinoma

Background:The increasing incidence of radiation-induced osteosarcoma of the maxilla and mandible(RIOSM) has become a significant problem that can limit long-term survival.The purpose of this study was to analyze the association of clinicopathologic characteristics with treatment outcomes and prognostic factors of patients who developed RIOSM after undergoing radiotherapy for nasopharyngeal carcinoma(NPC).Methods:We reviewed the medical records of 53,760 NPC patients admitted to Sun Yat-sen University Cancer Center during the period August 1964 to August 2012.Of these patients,47 who developed RISOM and met inclusion criteria were included in this study.Two of these 47 patients refused treatment and were then excluded.Results:For all patients treated for NPC at Sun Yat-sen University Cancer Center during the study period,the total incidence of RIOSM after radiotherapy was 0.084%(47/53,760).Two patients(4.4%) had metastases at the diagnosis of RIOSM.Thirty-nine of the 45(86.7%) patients underwent surgery for RIOSM;most patients(24/39;61.5%) who underwent resection had gross clear margins,with 15 patients(38.5%) having either a gross or microscopic positive margin.All patients died.The 1-,2-,and 3-year overall survival(OS) rates for the entire cohort of 45 patients were 53.3%,35.6%and 13.5%,respectively.The independent prognostic factors associated with high OS rate were tumor size and treatment type.Conclusions:RISOM after radiotherapy for NPC is aggressive and often eludes early detection and timely intervention.Surgery combined with postoperative chemotherapy might be an effective treatment to improve patient survival.

Effects of different types of palatal lateral excisions on growth and development of maxilla and dental arch

Objective:This study aimed to explore the effects of different types of palatal lateral excisions on the growth and development of the maxilla and dental arch, and to investigate the underlying mechanisms. Methods: A total of 112 3-week-old Sprague-Dawley (SD) male rats were randomly divided into a control and 3 experimental groups: the mucoperiosteal denudation group, the mucosal flap excision group, and the periosteum excision group. In the experimental groups, bilateral mucoperiosteal, mucosal flap and periosteum were excised respectively in the lateral one half of the palate. Four rats in each group were randomly chosen for sacrifice every two weeks. The maxilla was dissected following the excision. The widths of the maxilla and dental arch were measured and the histological phenomena were investigated at different phases. At the same time, 12 animals in each group were sequentially injected with calcein every two weeks. Three animals in each group, whose fluorescent labeling was used, were sacrificed for investigating bone formation at Week 8 following injection. Results: (1) Each experimental group presented the constriction of the maxilla and dental arch. The upper first molars in the experimental groups inclined medially. The mucoperio-steal denudation group showed the largest degree of effect followed by the periosteum excision group. The indices of the mucosal flap excision group, which retained the structures of the periosteum layer, had the most approximate values to the control group; (2) Different histological changes among the experimental groups were detected. The fibers penetrated into the palatal bone as Sharpey's fibers in the mucoperiosteal denudation group. The pattern of bone deposition was the bundle type. Sharpey's fibers were not found in the mucosal flap and periosteum excision groups and the depositions of palatal bone were the lamellar type as those in the control group; (3) The rates of bone deposition in the experimental groups decreased compared with the control group. The rates in different phases were the most approximate values to those of the control group in the mucosal flap excision group, which has the same structure of periosteum as the control group. Conclusion: There were different effects on the growth and development of the maxilla and dental arch in different types of palatal lateral excisions. Periosteum is important for bone for-mation and deposition pattern. The prevention of Sharpey's fibers forming and attaching to the palatine can effectively avert the following malformation.

Adenoid cystic carcinoma in the maxillary gingiva: a case report and immunohistochemical study

Gingival adenoid cystic carcinoma (ACC) is a rare malignancy. We describe the diagnosis and treatment of a 43 year- old woman who presented with a persistent oral ulcer for approximately 1 year, and subsequent pain in the left posterior maxillary region. Clinical examination revealed an ulcer in the left upper molar gingiva, with swelling in the region from the second premolar to the third molar. X-ray images demonstrated the involvement of the maxillary alveolar bone. The histopathological and immunohistochemical features were diagnostic of ACC. ACC is often presented as a gingival lesion; thus, it may easily be neglected by patients. The identification of this tumor using specific pathological analyses prevents misdiagnosis and enables clinicians to determine the appropriate treatment. In this case, no recurrence or distant metastasis was observed after 2 years of follow-up.

Angiosarcoma of Maxillary Sinus: A Case Report

Purpose: To describe a rare malignancy involving the sinonasal cavities. To discuss the clinical, diagnostic, and treatment modalities. Study Design: A case report including histopathological, radiological analysis and review of literature. Method: A case report is described from a tertiary care centre. Histopathological and radiological details are reviewed. Results: This case report presents a 29 year old male with 3 days history of bleeding from the left nostril, blood stained saliva with post nasal discharge and head ache. Biopsy demonstrated poorly differentiated Angiosarcoma. On immune stains the tumor cells showed diffuse strong cytoplasmic membrane positivity with CD 31 and few cells are positive for CD34. FLI-1 is also positive. Conclusion: Angiosarcoma is a rare malignancy involving the sinonasal cavities. Multidisciplinary approach is essential to obtain clear diagnoses and appropriate treatment plans.

Investigation of Peri-implant Status and Risk Variables for Implant Failure in Body of Maxilla after Oral Tumor Surgery

The aim of this study was to assess the peri-implant parameters and evaluate the clinical status with the survival of dental implants in body of maxilla after treatments of oral tumor. A follow-up examination included 27 patients who underwent the ablative tumor and （or） reconstructive surgery during a 5-year period. The follow-up protocol included clinical examination, radiological evaluation, and an interview using a standardized questionnaire. The reasons related to implant failure were studied by comparing the amount of failure with the value of marginal bone resorption, probing pocket depth, and plaque index using statistical t-test. The relationship between smoking and implant failure was analyzed statistically by chi-square test. The results showed among the 112 implants observed after implant loading, 29 have failed with the failure rate being 22.14 %. There was no significant correlation between the peri-implant status and the implant failure （P〉0.05）, however, the association of smoking and implant failure was statistically tested （P〈0.05）. It was suggested that the association of peri-implant status and implant failure in the maxilla after tumor surgery can＇t be statistically tested, however smoking was still a mainly significant factor.

Intraosseous venous malformation of the maxilla after enucleation of a hemophilic pseudotumor: A case report

BACKGROUND Hemophilic pseudotumor(HP)is a rare complication in patients with hemophilia.The lesion most frequently occurs in the long bones,pelvis,small bones of the hands and feet,or rarely in the maxillofacial region.Postoperative changes in HP are seldom arrested,whereas angiogenesis characterized by disturbed wound healing in HP may cause vascular malformations.CASE SUMMARY We report the case of an 11-year-old boy who was affected by maxillary intraosseous venous malformation.Enucleation of an HP without factor replacement was performed initially on the right side of the maxilla 3 years ago.The patient was referred to us because of painless swelling in the same location.Factor replacement and subtotal maxillectomy were performed.Pathological examinations revealed intraosseous venous malformation.CONCLUSION This study is the first to document the development of intraosseous venous malformation after enucleation of an HP in the maxillofacial region.Angiogenesis characterized by disturbed wound healing in patients with hemophilia may be pivotal in the pathogenesis of this condition.

A protocol used to manage maxillary hypoplasia in cleft lip and palate patients

Objectives: We report our experience and the protocol we used in managing maxillary hypoplasia in cleft lip and palate patients. Patients and methods: 14 adult cleft lip and palate patients with maxillary hypoplasia were evaluated clinically. Dental models and radiographs including (lateral cephalograms and orthopantographs) were obtained at the initial visit and upon completion of the presurgical orthodontic treatment. Patients with occlusal discrepancies larger than 6 mm and severe palatal scaring underwent Distraction osteogenesis (DO) to advance the maxilla. Patients with an occlusal discrepancy of 6 mm or less, underwent traditional orthognathic surgery including le fort I advancement and Bilateral sagittal split osteotomy (BSSO) to seat the mandible in occlusion. Results: Five patients underwent orthognathic surgery. Two of them underwent double jaw surgery. Three underwent single jaw conventional le fort l advancement. Four patients required bone grafting to repair the residual alveolar defect and to augment the midface deficiency. Nine patients with severe maxillary hypoplasia underwent maxillary advancement using distraction osteogenesis. Conclusion: Patients with a severe maxillary hypoplasia of 6 mm or more and excessive palatal scaring are successfully treated with DO. Conventional le fort I is reserved for patients with less severe maxillary hypoplasia. Both techniques gave promising results providing having followed the proper selection criteria.

Evaluation of speech function on repairing defects of maxilla and palate with temporalis muscle flap

Objective： To evaluate the speech function on repairing defects of maxilla and palate with temporalis muscle flap after benign or malignant turmor resection. Methods： The lateral cephalogram and speech intelligibility were detected in 19 cases with the operations of repairing defects of maxilla and palate by temporalis muscle flap, and their recovery of the speech function were analyzed. Results： Among the 19 patients, there were 15 cases （78.00%） with complete velopharynx, 3 cases （15.80%） with mafiginal velopharynx, and 1 case （5.26%） with insufficient velopharynx. The average speech intelligibility was 94.3%, close to the normal speech intelligibility. Conclusion： The operation of repairing defects of maxilla and palate with temporalis muscle flap can reconstruct the phonatory structure, preserve the palate function and restore the speech function after operation.

An Aggressive Ameloblastic Fibroma in Maxilla of a 5-Year-Old Child—Reconstruction of the Defect with Buccal Flap Advancement—A Conservative Approach

Ameloblastic fibroma (AF) is a rare tumour of mixed odontogenic origin that can occur either in mandible or maxilla but is most frequently found in the posterior region of mandible. Age of occurrence is generally between first and second decades of life. It is often mistaken for a den tigerous cyst due to presence of an impacted tooth. The diagnosis of AF usually occurs accidentally by routine radiographic examination for an impacted tooth. Histologically it consists of odontogenic ectomesenchyme resembling the dental papilla, epithelium resembling dental lamina and enamel organ without dental hard tissues. There is controversy in the literature as to whether the treatment should be conservative or a radical resection should be done. A conservative treatment strategy, such as enucleation and curettage, is usually sufficient. We describe a case of massive ameloblastic fibroma in a 5-year-old child with an unusual position in maxillary posterior region and without any impacted tooth. Surgical resection of the tumor through Weber Ferguson approach was done under GA with 2 years of follow-up without any recurrence.

A Comparative Study of Bone Resorption between Implant Placement Sites and Non-Implant Placement Sites after Autogenous Block Bone Grafts in the Anterior Maxilla

The aim of this study was to compare the bone resorption differences between implant placement sites (IPS) and non-implant placement sites (NIPS) after autogenous block bone grafts in the anterior maxilla. Fourteen patients (58 edentulous sites) with alveolar atrophy in the anterior maxilla were treated with autogenous block bone grafts. CBCT examinations were performed at 1 month before surgery (T0), immediately after surgery (T1), 3 to 4 months after surgery (T2), 6 to 7 months after surgery before implant placement (T3), 12 to 13 months after surgery (T4), and the longest follow-up point (T5). Alveolar crestal and basal bone width (ACBW, ABBW), and alveolar bone height (ABH) were measured and divided into IPS (30 sites) and NIPS (28 sites). All results were compared by the Wilcoxon Signed Rank test. The bone resorption changes for both groups were the same. For these three parameters, ACBW didn’t change significantly from T2 to T3 and T4 to T5, ABBW didn’t change at every period from T2 to T5, and ABH didn’t change from T4 to T5. The bone resorption volume of ACBW and ABH in NIPS were more than in IPS after implant placement surgery, while the volume of ABBW was similar in both groups. At T5, the bone resorption percentages of ACBW, ABBW, and ABH were 25.57%, 16.85% and 43.84% in IPS, and 33.55%, 15.92% and 46.44% in NIPS. A more rapid loss of alveolar crest in NIPS resulted from implant placement surgery, and this reminded us of the importance of immediate implant placement.

Maxillary Distraction Osteogenesis

Background: Distraction Osteogenesis is popular for long bones. And nowadays it has found its role in facial bone deficiency treatments. Purpose: We used our special designed Distractor for advancement of Maxillary deficiencies in cleft lip and palate patients. The purpose of this paper is to compare the treatment of hypoplastic, posteriorly retruded maxillary of cleft palate patients using distraction osteogenesis vs. Le fort I orthognathic surgery for length of advancement, stability and relapse, growth after distraction and soft tissue expansion and soft tissue profile changes. Meterial & Methods: In group A only Le fort I and surgical maxillary advancement sometimes with bone graft were done. In group B we used our special Distractor for Distraction Osteogenesis and advancement of the Maxillary bone. Demographic data, length of retrusion of maxilla, time length of treatment, length of advancement and relapse, SNA and SNB angles were measured and included in the study. The results were compared in each group before and after advancement and between both groups. The rate of distraction was 0.5 mm twice per day to achieve normal occlusion with 2 mm overcorrection more than calculated measures. The devices removed after 10 weeks as latency period. Results: The SNA increased at the end of distraction (p < 0.001), with no significant relapse indicating stability at 1 year after treatment. The total length of advancement in group A was 17 ± 4 mm and in group B was 20 ± 3 mm. The difference between before and after measurements in each group was significant (p = 0.002, p = 0.003 respectively). The mean length of relapse in group A was 3 ± 1 mm and in group B was 1 mm. Discussion: For the deformities and retrusions less than 7 - 8 mm, the Orthognatic surgery is the treatment of choice, however for more retrusions (>10 mm) we recommend Distraction Osteogenesis, and it preferred to start it soon in younger ages.

Case Report: Osteoblastoma of the Maxillar Sinus

Osteoblastoma is an uncommon benign tumor which commonly affects the vertebrae and the long bones. It occasionally arises in the maxilla. It is important to do differential diagnoses which include osteoid osteoma, giant cell bone tumour, aneurysmal bone cyst and fibrous dysplasia giant cell tumor and osteogenic sarcoma. The current study presents the case of a 14-year-old boy with a tumor in the ethmoid cell and maxillary sinus. Previous literature was reviewed and discussed.

Brown Tumor of the Maxilla Revealing Primary Hyperparathyroidism

Brown tumor or localized form of osteitis fibrosa cystic is a focal lesion complicating hyperpara-thyroidism. It’s rarely revelatory of the clinical feature and corresponds to a mass with partly cystic and partly solid areas. A 65-year-old man, followed up for hypertension, complained of a progressive swelling in the left paranasal part of the face lasting for 3 months. Physical examination revealed a left paranasal swelling of 4 cm diameter, with a healthy looking skin. CT facial bones found a round formation of 2 cm involving the left maxilla. He received tumor resection by vestibular pathway. Histological examination showed many giant cells. We then discussed the brown tumor diagnosis. The PTH dosage was high: 645 pg/mL (normal: 15 - 68 pg/mL). The serum calcium was in the superior normal limit (100 mg/dL). Cervical ultrasound revealed a bottom left parathyroid nodule. A lower left parathyroidectomy was performed. Histological results confirmed parathyroid adenoma. Monitoring was marked by a marked decrease of the PTH serum level then a return to normal values, a normocalcemia and no recurrence of the maxillary tumor with Recoil of 14 months. Brown tumor of the maxilla is rare and should be considered even in absence of hypercalcemia.

Success Rate of Dental Implants Placed in the Atrophic Posterior Maxilla with Intentional Sinus Floor Perforation in Lieu of Indirect Sinus Augmentation: A Retrospective Report of 26 Consecutive Patients and Literature Review

Purpose: To assess surgical success rate of placing dental implants in the atrophic posterior maxilla engaging the maxillary sinus floor in patients with inadequate posterior maxillary alveolar bone height (PMABH). Methods: 26 patients with PMABH of 7 - 10 mm had 39 implants placed between July 2012 and June 2014. These implants were placed protruding apically 1 - 3 mm into the maxillary sinus engaging the sinus floor. At stage one, implants and cover screws were placed, followed by stage two, 5 - 6 months later. The implants were considered osseo-integrated in the absence of symptoms, mobility and inflammation. Periapical radiographs were taken to rule out peri-implant radiolucency. Restorative treatment was completed 2 months thereafter. Patients were scheduled to have a dental exam (6 - 12 months after delivery of prosthesis) and the implants were evaluated clinically and radiographically. A retrospective review was conducted to assess the surgical success rate of this treatment modality. Clinic charts, radiographs and digital implant log were reviewed for all patients with PMABH of 7 - 10 mm who received dental implants in the posterior maxilla to determine the success rate of this treatment modality. Results: 26 patients who had 39 implants placed were included in the study. All implants (100%) were osseo-integrated at the time of uncovering (stage 2). None of the implants (0%) had mobility or inflammation around them. Stage 2 was successfully performed on all 39 implants (100%). All implants (100%) in these patients had been restored, and were in good condition without mobility or inflammation, and had been functioning well 6 - 12 months after restoration. Conclusion: This study suggests that a high success rate can be attained placing dental implants in the posterior maxilla while perforating and engaging the cortical maxillary sinus floor. A future prospective study that compares this technique with the internal sinus lift would likely help elucidate this suggestion.

Extensive Odontogenic Myxoma of the Maxilla: A Case Report and Review of Literature

Odontogenic myxomas (OM), also called odontogenic fibromyxomas, are rare tumours of the jawbones. They are benign tumours that can be locally invasive and aggressive, but seldom undergo malignant transformation and do not give rise to metastases. They are often asymptomatic and present as painless swelling. We present herein the case of a 24-year-old patient, with an incidental finding of a maxillary lesion. The lesion expanded to the surrounding soft tissues of the face, the maxillary sinus, the nasal cavity and the ethmoidal cells. After confirmation of OM on biopsy, the patient underwent an extended right radical en bloc maxillectomy with immediate reconstruction of the inferior orbital rim. A literature review of clinical symptoms, radiological presentation, differential diagnosis and surgical management of OM is discussed.

Alveolar Ridge Preservation of an Extraction Socket of Fractured Maxillary Lateral Incisor

Background: Alveolar ridge resorption still continues to be a problem in oral surgery. Cause of bone resorption is including tooth extraction, periodontal disease and inflammatory periapical pathologies. Various methods and materials have been suggested to minimize this resorption. Aim: Goal of this case report is to present alveolar ridge preservation (ARP) following horizontally fractured maxillary lateral incisor with allograft in the aesthetic zone. Case presentation: 30-year-old female patient with fractured tooth was treated by grafting and insertion dental implant. Fractured tooth extraction was performed and extraction socket augmentation was performed by allograft and covered with collagen membrane. Augmented area was treated with bone-level implant. Definitive prosthesis single-tooth porcelain-fused-to-zirconia restorations were fabricated. Conclusions: Before implant insertion, extraction and grafting socket procedure is appropriate treatment for of fractured teeth with granulation tissue.

Juvenile cemento-ossifying fibroma of the maxilla:Report of one case and review of the literature

Juvenile cemento-ossifying fibroma (JCOF) is a rare lesion that exhibits a slow growing but may reach massive proportion and cause considerable cosmetic and functional problems. This lesion has the tendency for recurrence following incomplete excision. A case report of giant JCOF in a 46-year-old female with 23-year history is presented. Local excision and thorough curettage was performed and the normal skeletal structure was maximally preserved. 15-month follow up demonstrated no sign of recurrence.

超短种植体配置下穿颧骨种植定位方案的三维有限元分析

目的:探究上颌窦沟槽(sinus slot,SS)技术和经上颌窦外(extra sinus,ES)技术结合超短种植体行穿颧种植修复后的生物力学分布特点,为功能性修复上颌骨重度萎缩提供理论基础。方法:通过患者的高分辨计算机断层扫描(computed tomography,CT)资料建立有限元分析模型,虚拟化穿颧种植体分别置于SS和ES模型,并结合使用2枚或4枚超短种植体。分析种植体von Mises应力值及牙槽骨中的主应力值。结果:配置2枚超短种植体+2枚ES穿颧种植体的von Mises应力最大(292 MPa);而4枚超短种植体+2枚SS穿颧种植体的最小(184 MPa)。配置2枚超短种植体+2枚SS穿颧种植体的最高主应力值最大(31 MPa);而4枚超短种植体+2枚ES穿颧种植体的最小(12 MPa)。配置4枚超短种植体+2枚SS穿颧种植体的最低主应力值最小(-58 MPa);而2枚超短种植体+2枚ES穿颧种植体的最大(-81 MPa)。结论:2枚SS穿颧种植体结合4枚超短种植体可能在生物力学方面更安全地用于修复重度萎缩的上颌骨。