Posterior Mandibular Area Research Articles

Maxillary and Mandibular Split Crest Technique with Immediate Implant Placement: A 5-Year Cone Beam Retrospective Study.

This study aimed to test the effectiveness and reliability of the alveolar ridge-splitting technique in atrophic posterior arches, investigating the middle-term volumetric and clinical outcomes. Atrophic alveolar ridges in the maxillary and mandibular posterior areas were treated with the alveolar ridge-splitting/expansion technique (ARST), immediate implant placement, collagen sponges covering the defect, and healing by secondary intention. Areas were rehabilitated by fixed dental prostheses supported by dental implants. Changes in volume and width of the alveolar ridge were retrospectively calculated by comparing the x-ray tomography scans obtained before and 5 years after surgery. Report of failure in the case sheets was taken into account. Cross-sectional images were also used to assess the thickness of the labial alveolar plates at the implant shoulder. Nonparametric analyses of variance with post hoc and pair-comparison tests were performed with a level of significance of .05. A total of 38 patients were retrospectively selected (23 women and 15 men). Six patients underwent ARST surgeries in both the maxilla and the mandible and were excluded from statistical analysis. Differences between 16 maxillae and 16 mandibles and between 12 single crowns and 20 fixed partial dentures (FPDs) were searched. Episodes of minor swelling occurred within the first 2 days after surgery. Neither mucositis nor flap dehiscence had been registered. The mean values of buccal cortical thickness were 2.46 ± 0.49 mm and 1.15 ± 0.33 mm, respectively, in the maxillary and mandibular areas. After 5 years of survey, maxillary increases in alveolar ridge width and volume were +4.4 ± 0.4 mm and +295 ± 45 mm3, respectively, whereas the same outcome variables (+3.5 ± 0.7 mm and +217 ± 53 mm3) measured in the mandible appeared to be significantly smaller than those in the maxilla (P < .0001). One maxillary single implant failed. Cumulative survival rates at 5 years were 100% for mandibles and 95.5% (95% CI: 86.8% to 100%) for maxillae. Posterior areas of the maxilla displayed a higher increase in alveolar width and volume than mandibular areas, and even if it would be premature to draw survival conclusions at this stage without any statistical support, a lower cumulative survival rate was reported for the maxillary single implants.

Microbial evaluation of implant surface

Aim: The aim of the present study was to evaluate the microbial contamination in internal and external walls of cone morse implant walls. Methods: Eleven patients with edentulous mandibular posterior area were selected to received dental implants, divided into groups: submerged (S), non-submerged (NS), and immediately loaded (IL). Microbiological evaluations (microorganisms’ number, aerobic and anaerobic colony forming units (CFU) number and microorganisms’ qualification) were divided into internal and external collection of the implant walls, at different stages: T0 (surgical procedure), T2 (suture removal), T4 (reopening S group), T6 (suture removal S group), and T8 (abutment placement in S and NS). All data were submitted to statistical analyses, with confidence level of 0.05. Results: There was difference in number of microorganisms observed over time within the same group (p &lt; 0.05). A difference was observed in CFU when evaluated within the same group over time (p &lt; 0.05), except for the IL group. In internal collection, a predominance of non-formation of microorganisms was observed at T0 in all groups, while formation of Gram-positive Diplococci and Gram-positive Bacilli was observed at T8 (p&gt;0.05). In external collection, an increase in number of microorganisms was observed at T0. Conclusion: There was no difference in microbial contamination among the evaluated groups. The microorganism’s colonization changed over time.

Bone Ring Autogenous Graft and Immediate Implant Reconstruction in Atrophic Posterior Mandibular Area

Purpose: to evaluate clinical and radiographic outcome of bone ring grafting technique with immediate implant placement in fresh extraction socket in mandibular posterior area. Patients and methods: Clinical study was conducted on six patients, suffer from deficiency in vertical height at posterior mandibular area. Extraction and immediate implant reconstruction with symphyseal bone grafting in one-stage procedure. All steps of harvesting by trephine bur, implant osteotomy and placement within the socket were guided by computerized surgical stent for donor and recipient sites. Platelet Rich Fibrin (PRF) membrane was prepared to cover the implant at suture line. Patients were followed up clinically and radiographically by Cone Beam Computed Tomography (CBCT) at immediate,3 and 6 months postoperatively to evaluate the implant site and vertical bone height changes. Results: One successful case out of six showed excellent soft tissue healing with implant stability. Clinically one case showed sever infection at 2 weeks postoperatively with looseness of implant. Dehiscence and pain were found in 83.3% of the cases. Four cases had mild pain and one case suffered from severe pain, edema was mild in the majority of patients, numbness was found in 4 cases with 66.7%. CBCT results showed significant decrease in 3D dimensions of vertical bone height from immediate postoperative to 6 months with percentage of resorption (Buccally37.49±12.14, Lingually36.12±12.04, Mesially 39.55±15.05 and Distally10.92±0.76). Conclusion: From our study, Bone ring augmentation technique for fresh defective sockets with immediate implants at posterior mandibular area achieved low success rate, long procedure time and donor site morbidity.

Evaluation of the Influence of Bone Resorption on Dental Implant Systems Using Taguchi Method and Finite Element Analysis

Dental implants are currently the mainstay of dental restoration procedures. They are used to reestablish normal chewing functions for patients. Several studies have reported their high success rate, but post-op bone resorption at the implant site increases the risk of implant fracture, which is especially significant in the posterior mandibular tooth (PMT) area. This study focused on bone resorption at the PMT area to assess and understand the mechanism of implant failure. This study used three implant systems on the posterior mandibular area. Computer tomography (CT) scans and reverse engineering were used to construct mandible and implant systems. The Taguchi method and finite element analysis (FEA) were used to explore the role of biting force on the components of various implant systems in the development of bone resorption. The results of this study found that when the implant site with bone resorption takes a biting force, the stress on the implant is inversely proportional to implant diameter and proportional to its length. For the stress loading, cortical bone thickness does not play a significant role. Instead, the most significant factor is implant diameter, followed by implant length. For better operation outcomes, it is recommended to use implants of larger diameter and less length. Also, it is recommended to avoid the use of implants less than 4.5 mm in diameter, regardless of the implant system, in order to prevent early implant damage or fracture due to bone resorption.

Variations in Anatomical Landmarks of Mandible Using Cone Beam Computed Tomography - A Cross-Sectional Study

Background: Cone beam computed tomography (CBCT) is a diagnostic imaging modality for implant and surgical procedures in anterior and posterior mandibular area. It provides adequate information concerning maxillofacial regions, optimum image quality, excellent geometric accuracy, and low radiation dose. Aim: The aim of this study was to evaluate prevalence and anatomical variations in Mandible (Mandibular Incisive canal, Lingual Foramen, Mental Foramen, and Mandibular canal) in CBCT scans of the maxillofacial region. Methodology: All CBCT cross-sectional images of 40 study participants was analyzed for the presence of anatomical landmarks. All the anatomical parameters were compared with respect to age groups, dentition, gender, and right and left side and their respective distances from the inferior border of mandible and alveolar crest were measured using CS 3D imaging software (Kodak). Results: Lingual Foramen, Mental Foramen, and Mandibular Foramen were seen in all (100%) study samples, incisive foramen 83% and anterior loop in 25% of study samples. On statistical analysis, the difference of the mean distance of incisive foramen, mental foramen, anterior loop and mandibular foramen from lower border of mandible and alveolar crest was significant with relation to gender (P = 0.006) and with relation to dentate, partially dentate, and edentulous were found to be significantly different (P &lt; 0.001). Conclusions: Careful assessment of the anatomical landmarks is essential to avoid neurosensory and bleeding complications using CBCT.

Comparative Evaluation of Classical Inferior Alveolar Nerve Block and Gow-gates Nerve Block for Surgical Removal of Mandibular Third Molar: A Prospective Study.

Background:The most commonly used nerve block procedure to anesthetize the mandibular arch is the classical inferior alveolar nerve block (IANB). In 1973, Gow-Gates developed a new procedure known as the Gow Gates nerve block, to achieve anesthesia in the same area with fewer complications.Methodology:The study comprised 80 patients who reported for the surgical removal of impacted third molar. The patients were randomly assigned into two groups– Group I received Gow-gates nerve block and Group II were administered classical IANB. Positive aspiration, meantime for the onset of anesthesia, mouth opening before and after each block and pain during the surgical procedure were compared.Results:Group 1 yielded positive aspiration in 2.5% of the cases (one patient) and 15% had positive aspiration in Group 2 (six patient). The mean time taken for onset of anesthesia was 6.16 min in Group 1 as compared to 2.78 min in Group 2. While comparing the quality of anesthesia between the blocks, 87.5% of the patients in Group 1 and Group 2 had successful anesthesia equally i.e., 35 of the 40 patients fell into category 1 and 2 of the eight-point category rating scale in both the groups and the remaining five patients (12.5%) in both the groups had unsuccessful anesthesia.Conclusion:Both approaches offer quality anesthesia in the posterior mandibular area when meticulously followed. The percentage of unsuccessful anesthesia in the Gow-Gates group could be attributed to the inexperience of the operator. Postoperative comfort and patient satisfaction were greater in the other group.

Evaluation of Stress and Strain Magnitude in Tapered and Cylindrical Implant Surrounding Bone, Used for Restoration of Mandibular Teeth: Finite Element Analysis in All-on-Four Concept.

The prevalence of the elderly population increased in the 20th century, as described in the World Health Organization 2004 Annual Report. The use of tilted implants parallel to the anterior wall of the maxillary sinus or the mental foramen/inferior alveolar nerve has been proposed for the treatment of the atrophic edentulous ridge. The aim of this study was to evaluate stress and strain magnitude in tapered and cylindrical surrounding bones. A 3D finite element model of an edentulous mandible was constructed. Two models of implants were used: cylindrical and tapered BEGO Semados RI Implants. Four implants were inserted between the bilateral mental foramen according to All-on-Four concept, and a mandibular bar was designed to use with the All-on-Four bar supported models. A vertical and 30 degree vertical load of 100 N was applied to both cylindrical and tapered implants models. Strain and stress were analyzed with ANSYS software (ANSYS R18.0). The maximum stress and strain were applied in all axes for the posterior man-dibular areas in the crestal region of the bone, and for the anterior areas at the intraosseous contact site. Also, the stress and strain of the bone under force in all axes in all areas for tapered implants is less compared to that for cylindrical implants. We found that the highest rate of bone resorption occurs in the posterior areas near the junction of the fixture with the abutment of implant, and in the anterior areas near the end of the fixture of implant. Still, more research on the subject is needed.

Oral Plasmablastic Lymphoma: A Case Report of an HIV Negative Patient with an Unusual Clinical Signature

Plasmablastic Lymphoma (PBL) is an aggressive variant of diffuse large B-cell lymphoma with a low survival rate. It is associated with Human Immunodeficiency Virus (HIV) infection but also affects patients with autoimmune diseases as chronic lymphocytic leukaemia, systemic lupus erythematosus and with long-term immunosuppression for heart and kidney transplants, ulcerative colitis. It has been reported in immunocompetent and HIV negative patients, determining the diagnosis more challenging. A rare case of bleeding gingival hyperplastic PBL in the left posterior mandibular area in a 61-year-old HIV negative male patient is reported. Histological assessment showed that oral mucosa was infiltrated by a monomorphic population of large lymphoid elements with morphological characteristics similar to immunoblasts with a “starry sky” appearance. Immunohistochemical markers were positive for CD138, Kappa and Lambda light chains, and negative for CKAE1/3, Synaptophysine, Chromogranin, CD56, and CD20. The detection of the primary oral manifestation of PBL remains challenging in immunocompetent patients and this case report aims to broaden the knowledge of the possible oral clinical aspects of PBL.

Periimplant bone changes in different abutment heights and insertion timing in posterior mandibular areas: Three-year results from a randomized prospective clinical trial.

To compare the influence of the abutment height and its insertion timing on the marginal bone change (MBC) variation of implants placed at posterior mandibular partial edentulous areas in a medium follow-up period. This randomized clinical trial (RCT) comprised a sample of patients with posterior mandibular edentulous areas, treated with at least two implants and distributed into three groups: implants connected to a 2mm height abutment during the surgical stage (Group A); implants connected to a 1mm height abutment during the surgical stage (Group B); and implants connected to a 2mm height abutment after 2months (Group C). Clinical and radiographic measurements were performed during a 36-month period (T4). The MBC was set as the main variable in study. Statistical significance was set at 0.05. A total of 29 subjects and 59 implants were enrolled in this study. A mean MBC of 0.35±0.46mm, 0.60±0.81mm, and 0.71±0.90mm was computed for groups A, B and C, respectively, at T4. Significant differences were found between groups A and C in terms of MBC variation after 3years of treatment (p=.048). Multiple linear regression analysis showed a significant influence of the first-year MBC and the abutment insertion timing has independent predictor variables for the MBC assessed at T4. The installation of 2-mm prosthetic abutments, at the time of implant placement, in areas with limited keratinized mucosa presents as a favorable treatment option in terms of periimplant marginal bone maintenance.

Biomechanical effects of dental implant diameter, connection type, and bone density on microgap formation and fatigue failure: A finite element analysis

Understanding fatigue failure and microgap formation in dental implants, abutments, and screws under various clinical circumstances is clinically meaningful. In this study, these aspects were evaluated based on implant diameter, connection type, and bone density. Twelve three-dimensional finite element models were constructed by combining two bone densities (low and high), two connection types (bone and tissue levels), and three implant diameters (3.5, 4.0, and 4.5 mm). Each model was composed of cortical and cancellous bone tissues, the nerve canal, and the implant complex. After the screw was preloaded, vertical (100 N) and oblique (200 N) loadings were applied. The relative displacements at the interfaces between implant, abutment, and screw were analyzed. The fatigue lives of the titanium alloy (Ti-6Al-4V) components were calculated through repetitive mastication simulations. Mann-Whitney U and Kruskal-Wallis one-way tests were performed on the 50 highest displacement values of each model. At the implant/abutment interface, large microgaps were observed under oblique loading in the buccal direction. At the abutment/screw interface, microgap formation increased along the implant diameter under vertical loading but decreased under oblique loading (p < 0.001); the largest microgap formation occurred in the lingual direction. In all cases, the bone-level connection induced larger microgap formation than the tissue-level connections. Moreover, only the bone-level connection models showed fatigue failure, and the minimum fatigue life was observed for the implant diameter of 3.5 mm. Tissue-level implants possess biomechanical advantages compared to bone-level ones. Two-piece implants with diameters below 3.5 mm should be avoided in the posterior mandibular area.

Influence of bone condition on implant placement accuracy with computer-guided surgery

BackgroundThe impact of the jaw bone condition, such as bone quantity and quality in the implant placement site, affecting the accuracy of implant placement with computer-guided surgery (CGS) remains unclear. Therefore, this study aimed to evaluate the influence of bone condition, i.e., bone density, bone width, and cortical bone thickness at the crestal bone on the accuracy of implant placement with CGS.MethodsA total of 47 tissue-level implants from 25 patients placed in the posterior mandibular area were studied. Implant placement position was planned on the simulation software, Simplant® Pro 16, by superimposing preoperative computed tomography images with stereolithography data of diagnostic wax-up on the dental cast. Implant placement surgery was performed using the surgical guide plate to reflect the planned implant position. The post-surgical dental cast was scanned to determine the position of the placed implant. Linear and vertical deviations between planned and placed implants were calculated. Deviations at both platform and apical of the implant were measured in the bucco-lingual and mesio-distal directions. Intra- and inter-observer variabilities were calculated to ensure measurement reliability. Multiple linear regression analysis was employed to investigate the effect of the bone condition, such as density, width, and cortical bone thickness at the implant site area, on the accuracy of implant placement (α = 0.05).ResultIntra- and inter-observer variabilities of these measurements showed excellent agreement (intra class correlation coefficient ± 0.90). Bone condition significantly influenced the accuracy of implant placement using CGS (p < 0.05). Both bone density and width were found to be significant predictors.ConclusionsLow bone density and/or narrow bucco-lingual width near the alveolar bone crest in the implant placement site might be a risk factor influencing the accuracy of implant placement with CGS.

A GIANT COMPLEX ODONTOMA ASSOCIATED WITH OSTEOMYELITIS: AN UNCOMMON PRESENTATION

Odontomas are odontogenic tumors/hamartomas composed of dental tissue in a variable proportion. They generally do not exceed 3 cm. The osteomyelitis is an acute or chronic process in the bone marrow or cortical space. Here we report an uncommon presentation and association between complex odontoma and osteomyelitis in a 30-year-old male patient. He reported to our service with a lesion of approximately 3.2 cm in length, yellowish color and hardened consistence, involving the left inferior posterior alveolar ridge, with 2 years’ of evolution. Physical exam also verified facial asymmetry. In the panoramic radiograph, a calcified mass with a radiolucent rim and heterogenous radiopacity, together with an impacted third molar, was seen measuring approximately 30 × 25 × 20 mm in the left posterior mandibular area with buccal cortical bone expansion and thinning. After the excisional biopsy and radiologic, tomographic, and histopathologic findings, the diagnosis of complex odontoma associated with osteomyelitis was confirmed. Odontomas are odontogenic tumors/hamartomas composed of dental tissue in a variable proportion. They generally do not exceed 3 cm. The osteomyelitis is an acute or chronic process in the bone marrow or cortical space. Here we report an uncommon presentation and association between complex odontoma and osteomyelitis in a 30-year-old male patient. He reported to our service with a lesion of approximately 3.2 cm in length, yellowish color and hardened consistence, involving the left inferior posterior alveolar ridge, with 2 years’ of evolution. Physical exam also verified facial asymmetry. In the panoramic radiograph, a calcified mass with a radiolucent rim and heterogenous radiopacity, together with an impacted third molar, was seen measuring approximately 30 × 25 × 20 mm in the left posterior mandibular area with buccal cortical bone expansion and thinning. After the excisional biopsy and radiologic, tomographic, and histopathologic findings, the diagnosis of complex odontoma associated with osteomyelitis was confirmed.

Adenomatoid Odontogenic Tumor in the Posterior Mandible of a Young Child : A Case Report

Adenomatoid odontogenic tumor (AOT) is a rare benign odontogenic jaw lesion. It usually occurs in the anterior maxilla and is mostly related to impacted canines in teenagers.&lt;br/&gt;A 3-year-old girl was referred from a local dental clinic due to delayed eruption of the right primary mandibular 2nd molar. There was no history of pain or swelling. Radiography revealed a large radiolucency lesion with radiopacities around the unerupted right primary mandibular 2nd molar. Surgical enucleation with extraction of the right primary mandibular 2nd molar and surgical biopsy were performed. Based on the clinical and radiological findings, this lesion was defined as an ameloblastic fibro-odontoma which often develops in the mandible of adolescents. However, this lesion was diagnosed as AOT from the results of the histological examination.&lt;br/&gt;This report aimed to present a rare case of AOT in the posterior mandibular area in a very young patient.

Retrospective clinical analysis of risk factors associated with failed short implants.

With advanced technology, short implants are more commonly used and have proven to have a relatively reliable curable efficacy. A consensus has not been reached regarding potential risk factors related to the loss of short implants. This large-sample retrospective study concentrated not only on patient characteristics and medical procedures but also on the features of implants in order to uncover the risk factors associated with short implants. Between 2014 and 2017, a total of 7001 implants were inserted at Nanjing Stomatological Hospital, Medical School of Nanjing University. Among the all, 1236 short implants were included after being evaluated according to the inclusion and exclusion criteria. In organizing the detailed information, seven variables including bone grafting procedure, age, gender, diameter of the implant, implant position, surface treatment, and definitive restorations were taken into consideration. The χ2 test, Kaplan-Meier test, logistic regression, and multifactorial Cox regression analysis were employed to explore the risk factors. The cumulative survival rate of short implants was 96.36%, slightly lower than that of the standard implants (98.16%, P < .001). Most of the short implants (84.44%) were lost at the early stage, mainly because of infection. Based on the results, male gender, implants treated by titanium anodizing and single-crown restoration increased the loss rate of short implants. Comparison of the short implants inserted into the maxillary and mandibular posterior area alone showed that the maxillary molar area was a risk factor for prognosis. Male gender, TA surface treatment, and the presence of a single crown were associated with an increasing rate of short implants loss. Examination of the implant location focused on the posterior area revealed the maxillary posterior area to be a risk factor.

CHERUBISM: IMPORTANCE OF REGULAR FOLLOW-UP AND MAINTENANCE OF HIGH-STANDARD ORAL CARE

Cherubism is a rare developmental condition of the gnathic bones that is usually inherited as an autosomal dominant trait with variable expressivity. An 11-year-old girl was referred because of an asymptomatic bilateral facial progressive swelling. Medical history was noncontributory. Locoregional physical examination revealed a bilateral firm swelling in the cheek and retromolar area covered by normal skin and normal oral mucosa, respectively. Panoramic radiograph and cone beam computed tomography scans showed bilateral extensive multilocular lesions in the mandibular posterior areas. Clinical diagnosis was cherubism, and histologic analysis of the specimen obtained by an incisional biopsy confirmed this hypothesis. The patient has been followed up and is under orthodontic treatment with satisfactory results.

Hybrid Central Odontogenic Fibroma with Central Giant Cell Granuloma Like Lesion ; A Case Report and Review of the Literature

The combination of central odontogenic fibroma and central giant cell granuloma is extremely rare and has been reported in only 46 cases worldwide in previous articles. The lesion is called a hybrid central odontogenic fibroma with central giant cell granuloma like lesion (HCOF-CGCG) due to a histopathological characteristics of multinucleated giant cell and odontogenic epithelium in fibro-cellular background. We report a case of HCOF-CGCG in a 27-year old Thai male patient who was identified as the first case in Thailand. Radiographic examination showed a well-defined radiolucency lesion at posterior mandibular area. Enucleation and curettage were done and microscopic study revealed a fibro-cellular proliferating tissue containing numerous strands, cord of odontogenic epithelium, and numerous multinucleated giant cells. This report also included a literature review of the previous 45 cases.

Fracture Resistance of Monolithic Zirconia Crowns in Implant Prostheses in Patients with Bruxism.

The aim of this study is to determine the minimum required thickness of a monolithic zirconia crown in the mandibular posterior area for patients with bruxism. Forty-nine full zirconia crowns, with seven different occlusal thicknesses of 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 mm, were made by using a computer-aided design/computer-aided manufacturing system (CAD/CAM). Seven crowns in each group were subjected to cyclic loading at 800 N and 5 Hz in a servohydraulic testing machine until fracture or completion of 100,000 cycles. Seven finite element models comprising seven different occlusal thicknesses of 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 mm were simulated using three different loads of vertical 800 N, oblique 10 degrees 800 N, and vertical 800 N + x N torque (x = 10, 50, and 100). The results of cyclic loading tests showed that the fracture resistance of the crown was positively associated with thickness. Specimen breakage differed significantly according to the different thicknesses of the prostheses (p < 0.01). Lowest von Mises stress values were determined for prostheses with a minimal thickness of 1.0 mm in different loading directions and with different forces. Zirconia specimens of 1.0 mm thickness had the lowest stress values and high fracture resistance and under 800 N of loading.

Frecuencia de quistes odontogénicos en pacientes de la Facultad de Odontología, Universidad Nacional de Colombia

Antecedentes: Los quistes odontogénicos se caracterizan por ser asintomáticos. Su hallazgo depende en un 80 % de imágenes radiográficas y en un 20 % de sintomatología esporádica. Colombia presenta pocos datos epidemiológicos sobre esta patología. Objetivo: Describir la frecuencia de los quistes odontogénicos, según la clasificación de la OMS del 2017, en los pacientes de la Facultad de Odontología de la Universidad Nacional de Colombia, sede Bogotá. Métodos: Se realizó un estudio descriptivo de corte transversal. Se seleccionaron historias clínicas con diagnóstico de quiste odontogénico corroborado por análisis histopatológico, y que tuvieran correctamente diligenciados los datos de edad, sexo y localización (zona afectada). Se usó la prueba de Fisher para evaluar independencia entre variables (p=0,05). Resultados: Los quistes odontogénicos más frecuentes fueron: quiste dentígero (66,6 %), quiste radicular (22,2 %) y queratoquiste odontogénico (11,2%). El 77,7 % se diagnosticó en hombres. 38.9 % de ellos se diagnosticaron entre la primera y segunda décadas de la vida (p=0,041) y la zona posterior mandibular fue la más afectada en un 44,4 % (p=0,017). Conclusiones: El quiste dentígero se presentó más durante la segunda década de la vida, en hombres y en la zona mandibular posterior. El quiste radicular no mostró predilección por un sexo, se presentó durante y después de la cuarta década de la vida y afectó la zona maxilar anterior. El queratoquiste odontogénico no tuvo predilección por sexo o zona afectada y se presentó en dos décadas de la vida diferentes.

Computed tomography-aided descriptive analysis of maxillary and mandibular atrophies

IntroductionThe aim of the present retrospective chart review was to analyze by Computed Tomography (CT) scan technique the degree of maxillomandibular atrophies, searching for differences between totally- and partially-edentulous subjects, and possibly identify and classify maxillomandibular atrophy staged patterns for implant planning in both totally- and partially- edentulous jaws. Material and MethodsCT scans of 89 mandibles and 77 maxillae from 111 patients were classified according to six different patterns of residual ridge resorption and to two different groups of edentulism (totally- and partially-edentulous). Maxillomandibular absolute linear dimensions were calculated and results compared for statistically significant differences by Wilcoxon tests. ResultsMaxillomandibular CT cross-section interpretation showed different patterns of linear bone remodelling (height values) between the two groups of edentulism joined with specific positions in the maxilla or mandible. The judgment of the investigator was uncertain in the analysis of the mandibular posterior areas with similar percentages for both totally- and partially-edentulous groups (12.5% and 11.5%, respectively). DiscussionThe 3D analysis is self-explanatory and easy to apply, aided by CT scans. The measurements between the referring planes and inviolable anatomical structures (nasal floor NFD, lower border of mandible LBD, inferior alveolar nerve AND, and sinus floor SFD), showed that class III may not guarantee an optimal implant placement, especially in the totally-edentulous group, due to a major degree of pneumatisation.

Assessment of two different Splinting materials on the immediate functional loading of Implants placed in mandibular unilateral free end saddle cases

Background: The class II Kennedy mandibular removable partial denture has many problemsas the different nature of support as well as crossing the arch for stabilization. The Target of thiswork was to evaluate the changes that occurs in the supporting structures of the implantsplaced in class II Kennedy cases as a result of two different types of splinting materials.Materials and Methods: Thirty implants were placed in ten patients with unmodifiedmandibular Kennedy Class II. For each patient, three implants were placed at the premolar/molarmandibular region. All the implants were immediately loaded following an Immediate FunctionalLoading Protocol. Patients were divided into two equal groups; Group A: received superstructuresthat were splinted with acrylic resin while Group B; received superstructures that were splintedwith metal. Radiographic evaluation using dental CT was carried out at intervals of 0, 6, 12 and24 months after implant surgery.Results: The results comprised the assessment of the bone height changes surrounding thethree implants placed unilaterally in the posterior mandibular areas of ten patients as a result of twodifferent splinting materials; the acrylic resin and the chrome cobalt metal alloy. Statistical analysisshowed that there was a statistically significant difference in the mean bone height values along thewhole study period between both groups (P ≤ 0.05) where there was more favorable bone heightvalues and hard tissue reaction in Group B (metal splinting) than Group A (Acrylic splinting).Conclusion: Within the limitation of this study, it can be concluded that the rigid splintingand immobilization of immediately loaded implants by metallic superstructures reduced thetransmission of micro-motion to the implant bodies and improved peri-implant bone reaction incomparison with the use of the less rigid acrylic resin material.