Maxillary Posterior Region Research Articles

A Huge Lesion in the Maxillary Posterior Region Diagnosed High Grade Mucoepidermoid Carcinoma of Minor Salivary Glands: A Case Report

Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of the minor and major salivary glands. These tumors occur commonly in the major salivary glands, especially the parotid, and they are the most frequently located in the palate intraorally. The similarity between MEC and other odontogenic cysts in the mouth is a critical situation that needs attention in clinical examination. Early diagnosis is very important in the diagnosis of asymptomatic growth, reaching very large sizes easily, its recurrence potential, and malignant character. The treatment and prosthetic rehabilitation of MEC are specified according to histopathological grade, location, and invasion pattern of the tumors. The purpose of this case is to present a 19-years-old female with high-grade MEC of minor salivary glands at the palate.

Osteotome sinus floor elevation with concentrated growth factor and simultaneous implant placement with or without bone grafting: a retrospective study

The aim of this study was to compare the clinical effects of osteotome sinus floor elevation (OSFE) combined with concentrated growth factor (CGF) and simultaneous implant placement with or without bone grafting in the maxillary posterior region, where the residual bone height (RBH) was 4–6 mm. A total of 44 patients who underwent OSFE combined with CGF and the simultaneous placement of 60 implants (group A, 31 implants with bone grafting; group B, 29 implants without bone grafting) were included in this retrospective study. The clinical indicators of implants were observed for 24 months. Sinus floor lift height was 6.02 ± 0.99 mm in group A and 5.81 ± 0.72 mm in group B (P = 0.360) after surgery. There was no significant difference in the vertical bone resorption between the two groups at 24 months (P = 0.097). Postoperative pain at 14 days (visual analogue scale) was significantly greater in patients with bone grafting when compared to those without bone grafting (P < 0.001). There was no significant difference in marginal bone loss (MBL) between the two groups (P = 0.707 for MBL during the first 12 months, P = 0.922 for MBL during months 12–24). The implant success rate was 100% with or without bone grafting. The technique of OSFE with CGF, either with or without bone grafting, is safe and reliable in patients with RBH 4–6 mm.

Central odontogenic fibroma of maxilla: A case report

Central odontogenic fibroma is a rare mesenchymal odontogenic neoplasm with a prevalence of 0.1 of all odontogenic tumors. Herein we present a case of a 63-year-old female with swelling in the left posterior maxillary region which was later diagnosed as a central type of odontogenic fibroma. A painless swelling was noted in the left maxillary tuberosity area. Orthopantamogram was advised which revealed a unilocular lesion with a mixed radiopaqueradiolucent appearance. This was associated with a spherically dense radiopaque mass in the left maxillary sinus region. A provisional diagnosis of the calcifying epithelial odontogenic tumor was made. An incisional biopsy was done and the specimen was sent for histopathological evaluation. The microscopic examination revealed inactive-looking odontogenic islands in the background of mature connective tissue stroma. Few foci of calcifications were also noted. After contemplating all the histological features a final diagnosis of central odontogenic fibroma was given. This case emphasizes the importance of histopathological examination of the unusual and rarely observed central odontogenic fibroma which can be missed due to similarities with other entities.nbsp

Prevalence and Location of Maxillary Sinus Septum and its Relation to Maxillary Sinusitis

Introduction: Maxillary sinus septum is an anatomical variation in the maxillary sinus. Sinus septum is also an important anatomical structure that complicates sinus lift procedure during dental implant placement. Objectives: To assess the prevalence and location of maxillary sinus septa and its relation to maxillary sinusitis using cone beam computed tomography (CBCT scan). Methods: An analytical cross-sectional study was conducted at the Department of Periodontics and Department of Oral Medicine and Radiology, Kantipur Dental College, Kathmandu, Nepal during July 2019 to June 2020 after ethical clearance. In total, 110 subjects and 220 maxillary sinuses were included in the study for evaluation by convenience sampling. The presence of septa, their location and association with maxillary sinusitis were evaluated. Data was analysed using SPSS software with Statistical level set at P&lt;0.05 for significance. Results: The prevalence of maxillary sinus septa in this study was 54 (49.09%). Statistically significant association was found between sinus septa with maxillary sinusitis (p=0.038) and location of septum in the arch (p=0.001). Conclusion: Presence and distribution of maxillary sinus septa is important in planning sinus surgeries and placement of implant in maxillary posterior region.

Maxillary sinus lift using osteotomes: An indirect approach for implant placement in atrophic posterior maxilla

The maxillary posterior edentulous region presents many challenges in implant dentistry. Deficient alveolar ridges often jeopardize the placement of implants in posterior maxilla. This problem mostly occurs when due to ridge resorption, sinus pneumatization is encountered. The procedure of choice is the elevation of the floor of the sinus with the use of the osteotome technique so as to increase the alveolar ridge height for the placement of implant. The purpose of this case report is to demonstrate indirect maxillary sinus lift procedure through alveolar crest using osteotomes to prevent perforation of sinus lining during implant placement and restoring the implants using early loading protocol.

Comparative Efficacy of Osteotome vs CAS Kit Assisted Indirect Maxillary Sinus Lift and Immediate Implant Placement in Posterior Atrophic Maxilla – A Study Protocol

Background: In today’s era implants are mostly used for replacing missing teeth. The greatest challenge for placing an implant is posterior maxillary teeth where the problems arise due to presence of maxillary sinus due which increases the risk of perforating the sinus membrane while implanting. In literature there are many techniques to overcome these problems and place the implant without perforating the sinus membrane. The current study is conducted to check either the traditional technique osteotome or modern technique CAS-Kit is better for placing an implant in posterior maxillary region.&#x0D; Objectives: The aim of these study is to compare and evaluate clinical and radiological outcomes of conventional osteotome technique and CAS kit use for indirect sinus lifting in atrophic posterior maxilla.&#x0D; Methodology: Two groups (study &amp; control) with 20 individuals requiring implant prosthesis in atrophic posterior maxillary region with RBH &lt; 3mm and minimum crestal width of 6mm are considered for the study model. After completion of osteotome and sinus lift procedure, integrity of sinus membrane will be checked by Valsalva manoeuvre. At three months after implant placement a second step surgery will be performed, stability of each implant will be checked. Marginal bone loss and amount of bone generation will be checked on Cone-beam computed tomography systems (CBCT) at 3, 6 &amp; 9 month interval.&#x0D; Expected Results: CAS kit is relatively newer and advanced equipment which is safer in placing implant in posterior atrophic maxilla without perforating sinus membrane with good amount of bone generation and stability of implant. with minimal marginal bone loss.&#x0D; Conclusion: Placement of an implant with CAS-Kit is better option than performing osteotome procedure which is time consumable with high chance of membrane perforation and large amount of marginal bone loss.

Palatal mucosa thickness and palatal neurovascular bundle position evaluation by cone-beam computed tomography-retrospective study on relationships with palatal vault anatomy.

BackgroundMeasuring the thickness of the palatal mucosa at the planning of the surgical procedure is an important step in order to obtain the maximum width and thickness of the graft from the appropriate area. The aim of this study is to determine whether there is a relationship between palatal angle (PA) or palatal depth (PD) and palatal mucosa thickness (PMT) or palatal neurovascular bundle distance (PNBD).MethodsPMT, PNBD, PD and PA were measured on cone-beam computed tomography (CBCT) images of maxillary posterior region of 200 male and 200 female patients. The mean of all parameters according to gender was compared and the significance of the difference detected between groups was evaluated. Potential relationship between PMT or PNBD and PA or PD was also evaluated.ResultsIn females, the palatal mucosa was significantly thinner at all tooth regions (p < 0.005), and PNBD was lower only at the level of the second molar (p < 0.001). In addition, it was found that there was a significant inverse correlation between the palatal depth value and the palatal mucosal thickness, and palatal depth was correlated with the palatal neurovascular bundle distance (p ≤ 0.001).DiscussionConsistent with previous studies, it was observed that the thickest mucosa in the palatal region was located in the region of the premolar teeth, and women had thinner palatal mucosa. In addition, in patients with a deeper palate vault, the palatal mucosa was thinner, but the palatal neurovascular bundle was more distant from the cemento-enamel junction.

Buccal Bone Thickness in Anterior and Posterior Teeth-A Systematic Review.

(1) Background: Immediate dental implant placement has been a subject of great interest over the last decade. Here, information regarding the anatomy and bone thickness of the jaw prior to dental implant placement is crucial to increase the surgery’s success and the patient’s safety. The clinical premises for this approach have been controversially discussed. One of those heavily discussed premises is a buccal bone thickness of at least 1 mm thickness. This meta-analysis aims to systematically review buccal bone thickness (BBT) in healthy patients. Thus, the feasibility of immediate dental implant placement in daily practice can be assessed. (2) Methods: A search in the electronic databases was performed to identify articles reporting on BBT that was measured by computed tomography in adults. (3) Results: We were able to find 45 studies, including 4324 patients with 25,452 analyzed teeth. The analysis showed a BBT at the alveolar crest of 0.76 ± 0.49 mm in the maxillary frontal and of 1.42 ± 0.74 mm in the maxillary posterior region. In the mandible, the average measured values were similar to those in the maxilla (front: 0.95 ± 0.58 mm; posterior: 1.20 ± 0.96 mm). In the maxillary frontal region 74.4% and in the mandibular frontal region 61.2% of the crestal buccal bones showed widths <1 mm. (4) Conclusions: In more than 60% of the cases, the BBT at the alveolar crest is <1 mm in maxillary and mandibular frontal regions. This anatomic data supports careful pre-surgical assessment, planning of a buccal graft, and critical selection of indication for immediate implant placement, especially in the maxillary and mandibular frontal and premolar region.

Estimation of Surface Radiation Dosage to Thyroid Gland and Lower Abdomen While Using Intraoral Periapical Radiography: A Phantom Study.

Background and objectiveEvery dose of radiation has the potential to cause biological harm. Quantitative assessment of radiation doses to radiosensitive organs can aid dental professionals in taking the appropriate protective measures against radiation. This data may also be used among the general public to alleviate fears of radiation exposure in dental radiography. This study aimed to estimate the surface radiation dose at the level of the thyroid and lower abdomen during intraoral periapical radiography (IOPAR).Materials and methodsA total of 80 calcium sulfate (CaSO4) discs were utilized in this cross-sectional in vitro study to estimate the surface radiation dose at the level of thyroid and lower abdomen on a phantom model while using an IOPAR. After exposure, the discs were submitted to the Radiation Laboratory's "Personnel Monitoring Service" to measure the surface radiation dose. Mean and standard deviations were calculated using descriptive statistics for continuous variables. The Mann-Whitney U test was used to compare bi-variate samples of independent groups. All statistical analyses were performed using SPSS Statistics version 21.0 (IBM, Armonk, NY).ResultsThe results showed a statistically significant difference in radiation exposure between the maxillary anterior and mandibular anterior regions when the thermoluminescent dosimeter (TLD) was placed in the lower abdomen (p=0.000). When the maxillary and mandibular posterior regions were compared, there was a statistically significant difference in radiation exposure when the TLD was placed in the lower abdomen (p=0.000).ConclusionWhen the cone was positioned in the maxillary region, there was an increase in surface radiation dosage to the lower abdomen and thyroid.

Survival rates of ultra-short (

BackgroundShort and ultra‐short implants represent a predictable treatment, in terms of implant survival, with patients presenting insufficient available bone volumes. Moreover, single crown restorations represent a gold standard in terms of oral hygiene.PurposeThe aim of this retrospective study was to evaluate implant survival, marginal bone loss, and peri‐implant complications in 333 locking‐taper short and ultra‐short implants.Materials and MethodsImplants were placed in the maxillary and mandibular posterior regions of 142 patients. Clinical and radiographic examinations were performed at 5‐year recall appointments.ResultsAll implants placed consisted of 8.0‐, 6.0‐, and 5.0‐mm length, 38.14%, 34.53%, and 27.33%, respectively. Three hundred thirty‐two implants (one early failure) were rehabilitated with single crowns in 141 patients. In 45.48% of the implants the crown‐to‐implant ratio was ≥2, with a mean value of 1.94. Overall implant‐based survival after 5 years of follow‐up was 96.10%: 96.85%, 95.65%, and 95.60% for 8.0‐, 6.0‐, and 5.0‐mm length implants, respectively (p = 0.82). Overall patient‐based survival was 91.55%. Regarding crestal bone level variations, average crestal bone loss and apical shift of the “first bone‐to‐implant contact point” position were 0.69 and 0.01 mm, respectively. Setting the threshold for excessive bone loss at 1 mm, during the time interval from loading to follow‐up, 28 implants experienced loss of supporting bone greater than 1 mm: 19 of them (67.85%) were surgically treated with a codified surgical regenerative protocol. After 60 months, a peri‐implantitis prevalence of 5.94% was reported, with an overall implant success of 94.06%: 95.93%, 92.73%, and 93.10% for 8.0‐, 6.0‐, and 5.0‐mm length implants, respectively (p = 0.55).ConclusionLong‐term outcomes suggest that short and ultra‐short locking‐taper implants can be successfully restored with single crowns in the posterior area of the maxilla and mandible.

The Learning Curve of Artificial Intelligence for Dental Implant Treatment Planning: A Descriptive Study

Introduction: Cone-beam computed tomography (CBCT) has been applied to implant dentistry. The increasing use of this technology produces a critical number of images that can be used for training artificial intelligence (AI). Objectives: To investigate the learning curve of the developed AI for dental implant planning in the posterior maxillary region. Methods: A total of 184 CBCT image sets of patients receiving posterior maxillary implants were processed with software (DentiPlan Pro version 3.7; NECTEC, NSTDA, Thailand) to acquire 316 implant position images. The planning software image interfaces were anonymously captured with full-screen resolution. Three hundred images were randomly sorted to create six data sets, including 1–50, 1–100, 1–150, 1–200, 1–250, and 1–300. The data sets were used to develop AI for dental implant planning through the IBM PowerAI Vision platform (IBM Thailand Co., Ltd., Bangkok, Thailand) by using a faster R-CNN algorithm. Four data augmentation algorithms, including blur, sharpen, color, and noise, were also integrated to observe the improvement of the model. After the testing process with 16 images that were not included in the training set, the recorded data were analyzed for detection and accuracy to generate the learning curve of the model. Results: The learning curve revealed some similar patterns. The curve trend of the original and blurred augmented models was in a similar pattern in the panoramic image. In the last training set, the blurred augmented model improved the detection by 12.50%, but showed less accuracy than the original model by 18.34%, whereas the other three augmented models had different patterns. They were continuously increasing in both detection and accuracy. However, their detection dropped in the last training set. The colored augmented model demonstrated the best improvement with 40% for the panoramic image and 18.59% for the cross-sectional image. Conclusions: Within the limitation of the study, it may be concluded that the number of images used in AI development is positively related to the AI interpretation. The data augmentation techniques to improve the ability of AI are still questionable.

Comparing the secondary stability of dental implants: immediate gradual loading versus early loading protocol in the posterior maxilla

Abstract Introduction Loading of dental implants has been performed in different protocols to achieve a high success rate and to decrease oral handicap timing. Many factors can contribute to the proper selection of loading protocol. Objectives This study evaluated the effect of early and immediate gradual loading protocols on the secondary stability of dental implants, which was measured by resonance frequency analysis. Material and Methods Ten patients each received two implants in the posterior maxillary region. At one side implants were loaded by progressive gradual loading using healing caps while the other side implants were loaded by early loading protocol. The secondary stability of dental implants measured using resonance frequency analysis afters 6 weeks from implantation day. Results There was no statistically significant difference between (Progressive loading protocol) and (early loading protocol) groups where (p=0.863). The highest mean value was found in (Progressive loading protocol) (77.86 ± 15.74), while the lowest mean value was found in (early loading protocol) (76.29 ± 17.63). Conclusion Trans mucosal healing is possible in the posterior maxilla with a very high success rate, especially if the implant was inserted with high primary stability. However, strict oral hygiene measure is mandatory to avoid plaque accumulation which may lead to mucositis. Progressive loading with a healing cap is not of a great benefit to the patients in terms of bone training, and it might cause pain while replacing healing caps.

Crestal approach for the repair of the Schneiderian membrane perforated during transalveolar sinus elevation

Aim The most common complication during maxillary sinus floor elevation is perforation of the Schneiderian membrane. Most of studies presented repair procedures via a lateral approach, which can induce additional complications. Therefore, in the present study the procedure was performed via crestal approach. Case report This study included three patients who showed a low residual alveolar bone height in the maxillary posterior edentulous region and in whom the placement of implants with sinus floor elevation was planned via a transalveolar approach. Perforation of the sinus membrane occurred during the procedure, and so collagen dressing material was inserted through the drilling hole to cover the perforated membrane. Xenogeneic bone was grafted under the elevated sinus membrane, and implants were placed simultaneously. The final prostheses were delivered at 6 to 8 months after the surgery. There were no complications in any of the patients. Results All implants showed successful stability, and no specific clinical or radiographic complication was observed during follow-ups lasting 2 to 3 years. Conclusion A crestal approach can be a reliable option when repairing a sinus membrane that is perforated during transalveolar sinus floor elevation.

A Six-Year Prospective Comparative Study of Wide and Standard Diameter Implants in the Maxillary and Mandibular Posterior Area.

Background and Objectives: The aim of our study was to test whether wide diameter (6 mm) implants perform differently from standard diameter (4 mm) implants in terms of marginal bone level and survival rate. Materials and Methods: Our sample comprised 72 patients who underwent surgery; a total of 80 implants were placed in the maxillary or mandibular molar region. Patients were divided into two groups according to the diameter of the implant, and were followed up for six years after the final setting of the prosthetics. In the test group, 40 implants with 6-mm diameter were inserted; in the control group, 40 standard diameter implants were inserted. Using panoramic radiographs, we investigated mesial and distal marginal bone levels around the implant fixtures. Results: After the first implant surgery, three implants, including one wide diameter and two standard diameter implants, failed due to lack of osseointegration. We did not note any fixture fracture during the six-year follow-up. After loading, we observed a six-year survival rate of 97.29% with no statistically significant difference from standard diameter implants, with a survival rate of 94.87%. Conclusions: This study shows that 6-mm diameter implants may be considered in the presence of adequate alveolar ridge width in the posterior maxillary and mandibular regions.

DETECTING APICAL RADIOLUCENCIES USING DEEP LEARNING TECHNOLOGY: A PILOT STUDY

<h3>BACKGROUND</h3> Dentists rely on radiographs in making treatment decisions every day. However, if inattentively read, radiographs can lead to over- or undertreatment. <h3>OBJECTIVE(S)</h3> The objectives were to assess the diagnostic performance of a deep learning algorithm at detecting apical radiolucencies (ARs) on intraoral (IO) radiographs and compare the performance of the algorithm vs interpretation by experts. <h3>STUDY DESIGN</h3> A search was conducted using the University of North Carolina cone beam computed tomography (CBCT) referral database for volumes acquired for endodontic evaluation. The inclusion criteria consisted of permanent teeth that exhibited apical radiolucencies measuring ≥2 mm on CBCT with a diagnostic IO radiograph for the same site. The exclusion criteria included patients under 18 years old and CBCT and IO images acquired more than 6 months apart. After applying the inclusion and exclusion criteria, 192 cases were found. The CBCT volumes served as ground truth for the IO radiograph annotation. The IO radiographs were randomly assigned to one of 3 groups: 6 images, observer calibration; 54 images, training the artificial intelligence (AI) algorithm; 132 images, testing set. Additionally, 132 IO radiographs with no evidence of apical radiolucencies were included to serve as controls. For this pilot, 70 images were randomly selected to create a testing subset derived from the main control and positive testing sets. Three experts were presented with this testing subset and asked to independently determine locations of AR and confidence of presence using a 5-point Likert scale. <h3>RESULTS</h3> The standalone software performance results by tooth were as follows: Sensitivity was 93%, specificity was 88%, and the area under the receiver operating characteristic curve (ROC-AUC) was 94% (95% confidence interval [CI], 89%, 98%). The combined results of the experts were as follows: sensitivity was 87%, specificity was 97%, and ROC-AUC was 93% (95% CI, 88%, 98%). Notably, the software performance metrics were lowest in the maxillary posterior region. <h3>DISCUSSION/CONCLUSIONS</h3> Using a limited testing data set, AI provided comparable performance to expert observers for this task. Further AI training is necessary to increase the sensitivity and specificity of AR detection in the posterior maxillary region.

EVALUATION OF USING BUCCAL PAD OF FREE FAT TISSUE TRANSFER WITH IMMEDIATE IMPLANT PLACEMENT IN THE MAXILLARY POSTERIOR AREA (CLINICAL TRIAL)

Introduction: Implants placed immediately after tooth extraction; impose many challenges. One of them is the difference in size and form between the extraction socket and the simultaneously inserted implant. Soft tissue coverage of the implant area is considered substantial to attain bone filling adjacent to the implant. Objectives: Evaluation of free tissue graft of buccal pad of fat (BPF) for primary soft tissue closure with immediately placed implants in the maxillary posterior region. Methods: Ten patients aged between 20 to 45 years were selected from the outpatient clinic of Alexandria University requesting a dental implant to replace an unrecoverable maxillary posterior tooth. One stage surgery including tooth extraction, placement of an immediate implant, bone grafting material and autologous soft tissue graft from the buccal pad of fat was carried out. Clinical and radiographical follow up were done for six months. Results: 10 patients (6 females and 4 males; mean age 34 years) were followed for 6 months .Soft tissue healing, was uneventful with only minor postoperative complications. Bone density and bone thickness measurements were significantly improved after 6 months from implant placement with full bone recovery around the implants compared with the 3months results. Conclusion: Results of the study suggest that, the buccal pad of fat graft application is a new prospective modality for achieving primary soft tissue coverage over immediate implants. Keywords: immediate implants, buccal pad of fat, primary soft tissue coverage. Running Title: immediate implants with buccal pad of fat free graft.

Implant Insertion after Using of Oxidized Regenerated Cellulose as a Graft Material in a Transalveolar Maxillary Sinus Floor Elevation

A clinical study was conducted on sixteen patients, suffering from partially edentulous areas at the maxillary posterior region. Sixteen patients with 18 implants were divided randomly into two equal groups 8 patients with 9 implants in each group.

Biomechanical effect of an occlusal device for patients with an implant-supported fixed dental prosthesis under parafunctional loading: A 3D finite element analysis

Statement of problemWhether providing an occlusal device for a patient with bruxism and an implant-supported fixed dental prosthesis leads to improved biomechanics is unclear. PurposeThe purpose of this 3D finite element analysis (FEA) study was to evaluate the biomechanical behavior of 3-unit implant-supported prostheses under parafunctional forces with and without an occlusal device. Materials and methodsEight 3D models consisting of a posterior (type IV) maxillary bone block with 3 external hexagon implants (Ø4.0×7.0 mm) and 3-unit implant-supported prostheses with different crown connections (splinted or unsplinted) and an occlusal device under functional and parafunctional loading were simulated. The abutment screws were evaluated by von Mises stress maps, and the bone tissue by maximum principal stress and microstrain maps by using a finite element software program. ResultsAn occlusal device improved the biomechanical behavior of the prostheses by reducing stress in the abutment screws and stress and strain in the bone tissue. However, the use of an occlusal device was not sufficiently effective to negate the biomechanical benefit of splinting. ConclusionsThe use of splinted crowns in the posterior maxillary region with an occlusal device was the most effective method of reducing stress in the abutment screws and stress and strain in the bone tissue when parafunction was modeled.

Comparative Evaluation of Marginal Bone Loss and Implant Failure Rate in Smokers and Nonsmokers.

Background:Smoking impose various ill-effects on the alveolar bone concerning dental implants including reduced bone height, delayed healing of bone, poor peri-implant bone formation, increased bone loss, and peri-implantitis.Aims:The present clinical trial was aimed to analyze the smoking effect on dental implant survival rate as well as marginal bone loss in dental implants.Materials and Methods:Out of 86 patients, Group I had 43 patients who were smokers and Group II had nonsmokers. Following the implant placement, marginal bone loss radiographically and mobility were assessed clinically at 3, 6, and 12 months after implant loading.Results:The mean marginal loss seen in smokers at 3 months was 2.13 ± 0.21, 2.46 ± 0.09, 2.60 ± 0.0.92, and 2.74 ± 0.11 for maxillary anterior, maxillary posterior, mandibular anterior, and mandibular posterior regions, respectively. The 12-month recall visit showed a higher proportion of smokers having implant mobility. In smokers, 13.95% (n = 6) of the study participants had implant mobility, whereas 6.97% (n = 3) of the nonsmokers had mobility.Conclusion:Smoking is associated with long-term implant failure which is directly proportional to the duration ad frequency of smoking. Furthermore, smoking has a detrimental effect on dental implants and its surrounding bone.

A 3D finite element analysis of bone tissue in three-unit implant-supported prostheses configurations through varying configuration factors (single-unit and splinted crowns in straight-line and offset configurations) and implant lengths in the maxillary posterior region

The objective of the present study was to analyze the stress and microstrain on cortical bone tissue caused by occlusal forces on three-unit implant-supported prostheses placed in the maxillary posterior region through varying configuration factors and implant lengths using 3D finite element analysis. Fifteen three-dimensional models were simulated with the support of the In Vesalius, SolidWorks 2016, and Rhinoceros 4.0 software programs. Each three-dimensional model included a maxillary bone block corresponding to the region from the 1st premolar to the 1st right molar with three EH implants measuring 4.0 mm in diameter, which supported the three-unit metal-ceramic screw-retained prosthesis through varying configuration factors (single-unit and splinted crowns: straight-line and tripod design) and implant lengths (10, 8.5, and 7 mm × Ø4 mm). The FEMAP 11.4.2 program was used to generate the finite element models in the pre- and post-processing phases. Bone tissue was analyzed using Maximum Principal Stress (MPa) and Microstrain (με) maps. The highest stress/microstrain values were observed in oblique loading. In addition, splinting associated with the offset configuration generated improved biomechanical behavior. Furthermore, the association of short implants with longer implants did not exhibit any biomechanical benefits. Moreover, a reduced implant length (i.e., 7 mm) generated unfavorable biomechanical behavior. Splinting was effective in reducing the stress/microstrain on cortical bone tissue, especially when associated with the offset configuration of the implants. Also, an increased implant length decreased the stress/microstrain in the bone tissue, and splinted short implants presented similar biomechanical behavior to short implants associated with longer implants.