Maxillary Posterior Area Research Articles

Endodontic radiography - what’s displaying the radiograph? The yield of commercial computer screens vs. DICOM calibrated medical screens in endodontic radiography

ObjectiveA comparison between commercial computer screens and DICOM-calibrated medical screens for characterizing anatomy and diagnosing dental pathologies was performed. The aim of this study was to evaluate and compare the ability of each of those screens to identify root apices and widening of the periodontal ligament (PDL) in the posterior maxillary area.Materials and MethodsDigital X-ray images of 53 maxillary molar teeth were examined by means of a commercial computer screen and again two months later with a DICOM screen to compare their ability to help identify and diagnose PDL widening and to locate the root apices of those teeth.ResultsThe DICOM screen had a significantly better ability to identify widened PDLs (from 31.4% to 34.8% of the cases compared to 19% to 26.1% for the commercial screens, P < .001), depending upon the observer. The DICOM screen was also significantly superior in depicting the root apices compared to the commercial screens (from 77.4% to 83.6% of the cases compared to 56% to 66.7% for the commercial screens, P < 0.001), depending upon the observer.ConclusionDICOM-calibrated medical screens were significantly superior to commercial computer screens for identifying widened PDLs and locating the root apex in the posterior maxillary area.

Long-term effectiveness of UV functionalised short (≤ 6mm) dental implants placed in the posterior segments of the atrophied maxilla: controlled case series.

This study evaluated long-term effectiveness UV functionalised short implants (≤ 6mm) placed in the posterior segments of the atrophied maxilla. The study included 47 patients from 2018 to 2023 (aged 27 to 56years, 24 women and 23 men) without any systemic diseases, with unilateral/bilateral missing teeth and vertical atrophy of the posterior maxillary area. Total installed were 64 short UV-functionalized implants and 62 standard implants over 10mm in length in segments maxilla with sufficient bone parameters. Clinical, laboratory and cone beam computed tomography (CBCT) methods were used to plan implant therapy. The clinical indices included the following parameters: ISQ, MBL, OHIP-G scale. For short implants, the median ISQ at placement was 62.2 for primary stability and the median ISQ at 5months was 69.6 ISQ. For standard implant, the mean ISQ at placement was 64.3 ISQ, and ISQ after 5months was 71.6 ISQ. After 6months mean MBL short implants 0.87mm, after 1year 1.13mm, after 5years was 1.48mm. After 6months mean MBL standard implants 0.84mm, after 1year 1.24mm, after 5years was 1.58mm. Mean OHIP-G scores-patients satisfaction with the implant at 4.8 ± 0.3, satisfaction with the operation 4.6 ± 0.4; satisfaction with prosthetics 4.7 ± 0.5. Cumulative success rate 5years short implants was 96.7%, standard implants was 97.4%, and prosthesis cumulative survival rate was 97.2%. Short ultraviolet functionalized implants used in the posterior resorbed segment of maxilla have been shown to be a reliable alternative to sinus lift, demonstrating fewer complications, reduction in the number of additional surgical interventions and showed satisfactory long-term survival.

Research Progress on Titanium Implants for External Maxillary Sinus Augmentation

In patients with missing maxillary posterior teeth, the negative pressure generated by breathing leads to an increase in the gasification of the maxillary sinus cavity, as well as the absorption of alveolar bone due to the lack of physiological stimulation due to missing teeth. This often leads to insufficient bone height during implant restoration in the maxillary posterior tooth area, and maxillary sinus floor elevation surgery can effectively solve this problem. At present, there are two main techniques for lifting the maxillary sinus floor: internal lifting through the top of the alveolar ridge approach and external lifting through the lateral wall approach. Among them, the maxillary sinus alveolar ridge lifting surgery is widely used due to its advantages of small wound size, short surgical time, fewer postoperative complications, low cost, and easy acceptance by patients. With technological innovation, the indications for maxillary sinus floor elevation surgery have gradually expanded to cases with residual bone height (RBH) greater than 2 mm.

EVALUATION OF THE EFFECTIVENESS OF DIFFERENT METHODS SINUS FLOOR ELEVATION THE LATERAL APPROACH

Background: The posterior maxillary area sometimes has insufficient bone mass for dental implants. The augmentation of the sinus floor allows the implant to be placed in the posterior of the upper jaw. Purpose: The aim of this study was to compare the effectiveness antral balloon- assisted maxillary sinus elevation and traditional sinus floor elevation followed by bone graft and delayed implant placement the posterior maxillary area. Material and methods: A total of 68 patients, (aged 27 to 56 years, 32 women and 36 men), without any systemic diseases with unilateral/bilateral missing teeth and atrophy of the posterior maxillary area, who required an enlargement of the sinus prior to implant placement, whom the location of the sinus floor from the crest was 3-5mm, width ≥5 mm were included in the study between 2018 and 2021. Patients underwent a thorough clinical examination according to the generally accepted scheme. All patients were selected after meticulous evaluation of their medical histories and dental examinations, including OPG and dental Computed Tomography (CT) scans. Results: The sinus lift using balloon technique was performed successfully in patients 1 group, with no complications. In 9 patients 2 group, perforation of the sinus membrane occurred during the operation, sinusitis in 4 patients, graft failure in 3 patients. Regardless of the approach used, both approaches showed significant increases in bone mass gain. Though not statistically significant difference, balloon-assisted procedure showed more mean bone gain (8.4 mm) compared to osteotome -assisted procedure (8.1 mm). The mean amount of Marginal Bone Loss (MBL) in patients 1 group 3 years follow-up was 0.86 mm in patients 2 group showed significantly less marginal bone loss 1,16mm. The implant survival rate 3 years follow-up was in patients 1 group was 97.62%, in patients 2 groups was 95.2%. Conclusions: Research has shown that the balloon sinus lifting offers predictable, safe and effective results, and eliminates the complications associated with traditional side window techniques. However, further controlled clinical trials are needed to evaluate the efficacy and safety of these technique for their appropriate implementation in the field of oral implanotology.

Survival Rate of Dental Implants in the Irradiated Jaw Bones of Patients with Oral and Head &amp;amp; Neck Malignancies

Purpose: This study aimed to analyze and report the survival rate of dental implants in patients who underwent radiation therapy for head and neck malignancies. Materials and Methods: A total of 23 patients (male:female ratio = 13:10; mean age 61 years, range, 44–86 years) who underwent dental implant placement after radiation therapy between 2010 and 2020 were enrolled in this study. The cumulative survival rate (CSR) was analyzed using the Kaplan–Meier method, considering variables such as the location of the dental implant, radiation dose, and types of cancers that patients had. Implant placement was considered successful if it showed no mobility, did not cause pain or bleeding, or a minimal marginal bone level change at follow-up.Results: There were two cases of death during the follow-up period. Seven of the 83 implants failed. Among the seven failure cases, four implants were applied in the posterior mandibular area, one in the anterior mandibular area, and two in the posterior maxillary area. When each variable was considered, the CSR of the implant was 91.6%. The correlation between CSR, implant location, and the types of cancer was statistically significant. However, there was no correlation between the CSR and average radiation dose.Conclusion: The survival of implants in the irradiated area of the jaw was lower than that in the normal jawbone. The survival rate of the implants in the irradiated maxillary jaw was lower than that of the implants in the mandible. Additionally, the radiation dose was not significantly correlated with implant failure rate. Also, when compared between patients who had oral cavity cancer and other head and neck cancers, implant survival in patients with oral cavity cancer was lower than that in patients with other head and neck cancers.

Effectiveness of ultra-wide implants in the mandibular and maxillary posterior areas: a 5-year retrospective clinical study.

Ultra-wide implants may be used as a replacement if existing implants fail. This study was conducted to evaluate the factors influencing the prognosis and failure of ultra-wide implants. Patients and. This study evaluated whether sex, age, site, diameter, length, additional surgery, implant stability (primary and secondary), and reason for ultra-wide implant placement affect the 5-year survival and success rates and marginal bone loss (MBL) of ultra-wide implants. Seventy-eight ultra-wide implants that were placed in 71 patients (39 males and 32 females) from 2008 to 2010 were studied. One-way ANOVA analysis was conducted to evaluate the statistical significance of MBL according to the patient's sex, implant site, and diameter. Independent sample t-tests were used to determine the statistical significance of MBL analysis which was used to determine the significance of the 5-year success and survival rates related to the variables. One-way ANOVA was conducted to evaluate the statistical significance of sex, implantation site, diameter, and MBL. Independent sample t-tests were used to evaluate the correlation between implantability and MBL for implantation reasons, while additional surgery, length, and Kaplan-Meier analysis were used to evaluate 5-year survival and success rates. The mean age of patients was 54.2 years with a survival rate of 92.3% and a success rate of 83.3% over a mean 97.8-month period of observation. MBL averaged 0.2 mm after one year of prosthetic function loading and 0.54 mm at the time of final observation. Success rates correlated with primary stability (P=0.045), survival rates correlated with secondary stability (P=0.036), and MBL did not correlate with any variables. Ultra-wide implants can be used to achieve secure initial fixation in the maxillary and mandibular molar regions with poor bone quality or for alternative purposes in cases of previous implant failure.

Evaluation of Dental Implant Angulation on Marginal Bone Loss in Posterior Maxillary Area

Evaluation of Dental Implant Angulation on Marginal Bone Loss in Posterior Maxillary Area

Installation Immediate Implant with Sinus Lift Crestal Approach Technique: A Case Report of 4-year Follow-up

When the first dental implants were developed in 1977, implants were placed 6‒8 months after extraction. The long healing time involves absorption of the extraction socket alveolar bone and a prolonged treatment period. To solve this problem, an “immediate implant” was studied, which is placed immediately after tooth extraction. Along with the timing of implant placement, studies on sinus lift were also conducted to overcome the lack of vertical bone height due to the presence of sinus and resorption of alveolar bone in implant placement in the maxillary posterior area. In this case, extraction, sinus lift, and implant placement were performed simultaneously with a crestal approach through the extraction socket in a patient with insufficient vertical bone height for implant placement. As a result, the treatment period of 3‒4 months was shortened, and the number of surgeries was reduced. The implant has shown satisfactory results in both bone and tissue during a 4-year follow-up.

Techniques and Graft Materials Used in Maxillary Sinus Lift Procedure for Dental Implant Placement

Posterior quadrant of the maxilla consider as special challenges for use of implant active prostheses to restore dental function. Placement of Implant in the posterior part of maxilla influence hesitation due to the lack of sufficient alveolar bone height. This occurs due to the proximity of alveolar crest to the maxillary sinus because of sinus pneumatization, along with resorption of bone of the alveolar ridge secondary to tooth extraction, pathological lesion or trauma. Sinus lifting to augment atrophic maxillary posterior area to create space for implantation has been progressively widespread in latest years. In literatures 2 approaches have been designated for sinus lifting: the direct approach called also lateral approach and the indirect approach called also crestal approach.

Outcomes Following Hydraulic Pressure Indirect Sinus Lift in Cases of Simultaneous Implant Placement With Platelet-Rich Fibrin.

BackgroundTo achieve a better long-term prognosis in the posterior maxilla with poor quality of bone, the sinus lift must ensure bone regeneration till the apex of the dental implant for osseointegration. An indirect sinus lift is a minimally invasive procedure where simultaneous bone condensation is achieved. During the sinus lift procedures, different graft materials are used to gain the height of the bone in the sinus. The present study aimed to evaluate the outcomes of indirect sinus lift with hydraulic pressure and the simultaneous placement of implant using platelet-rich fibrin (PRF).MethodologyIn total, 24 subjects aged 18-74 years with missing maxillary premolars and first and second molars who opted for dental implants placed with indirect sinus lift with hydraulic pressure and had low sinus with less residual ridge height, bone density, and bone height were assessed at one day, one week, one month, three months, and six months.ResultsThe average mean height preoperatively was 5.573 ± 0.66 mm which showed a significant increase postoperatively to 9.603 ± 0.78 mm (p < 0.001). Mean sinus membrane lift was 4.8 ± 2.2 mm at six months. The implant stability quotient increased significantly at six months postoperatively from 69.07 ± 3.39 at the immediate postoperative time to 72.92 ± 2.714 at six months postoperatively (p < 0.001).ConclusionsThe current study suggests that minimally invasive indirect sinus lift with bone augmentation utilizing PRF increased residual alveolar ridge height and implant stability with fewer problems than previous sinus lift procedures in the posterior maxillary area.

Variations in the bony architecture of the greater palatine canal: An anatomical report

IntroductionThe greater palatine canal route has been well‐described in adults for the purposes of anesthetizing the branches of the maxillary division of trigeminal nerve for the relief of sphenopalatine neuralgia [11]. The canal also provides direct access to the contents of the PPF [12]. A complex array of vascular and neural structures characterizes this posterior maxillary region where the GPC is located. Its surgical anatomy can get further complicated by any anatomic variations and identification of vital structures becomes difficult, especially when bleeding during surgery obscures the region. Accurate knowledge of normal anatomy and common anatomical variations therefore remain crucial in minimizing intraoperative and postoperative complications associated with invasive microsurgical approaches to this region. The aim of this study was to explore the architecture of the GPC for any anatomic variations.Material &amp; MethodIn total, 30 adult dried and intact skull specimens were selected. The selection criteria included an intact hard palate with erupted 3rd molars and an intact lateral nasal wall on both sides. The exclusion criteria included any major craniofacial deformities, excessive bone resorption, very old specimens. The bony walls of the GPC were observed by passing a black wire.Findings4 out of 30 specimens showed marked variations in the bony medial wall of the greater palatine canal (GPC). Partial to complete malfusion between the posterior surface of the maxilla and the perpendicular plate of palatine bone was observed. This might be the result of embryological malformation.ConclusionThe present study provided information regarding the existence of some degree of anatomical variation in the bony architecture of greater palatine canal.SignificanceThis might help surgeons visualize over the possibility of the existence of any such variation while performing any surgical procedure in the posterior maxillary area. In order to establish the embryological basis of these findings, investigation on a larger number of specimens is highly suggested by the authors.

Causes of Emergency Bleeding after Nonsurgical Periodontal Therapy in Adult Periodontitis Patients: A Retrospective Analysis.

Background Emergency gingival uncontrollable bleeding after nonsurgical periodontal therapy (NSPT) could be caused by a variety of factors; local oral factors are the main cause of gingival bleeding in most patients. Because the doctor will do a good job of evaluating the patient's physical condition before nonsurgical periodontal therapy. This study is subjected to evaluate the possible factors associated with emergency uncontrollable bleeding within 24-48 hours after NSPT. Material and Methods. A total of fifty-eight patients with emergency bleeding after NSPT in the past four years were enrolled. The related factors in patients, such as age, gender, clotting function, systemic diseases, and baseline periodontitis severity, were analyzed. The site-related factors, such as tooth type, tooth distribution, and alveolar bone resorption at the bleeding site, were compared. The possible relationship of the parameters to the causes of emergency bleeding with NSPT was also evaluated. Results Gingival bleeding after NSPT was registered. In this retrospective study, a total of 58 patients were selected. There were 29 males and 29 females, aged from 20 to 67 years old, with an average age of 35.21 ± 10.09 years. Among them, 8.6% were over 50 years old, and 91.4% were under 50 years old. Completed evaluations were performed in 15.5% gingivitis and 84.5% periodontitis. The causes of emergency bleeding after nonsurgical periodontal therapy in this study were residual subgingival calculus or granulation tissue in 63.79% of cases: severe gingival inflammation, 29.32%; gum trauma, 3.45%; and poor compliance, 3.45%. The therapy method before bleeding includes supragingival scaling accounted for 72.4% and subgingival scaling accounted for 27.6%. 23 cases of horizontal absorption at the bleeding site accounted for 39.66%, and 35 cases of angular absorption accounted for 60.34%. Bleeding of maxillary posterior teeth accounted for 34.48%; mandibular anterior teeth accounted for 15.52%; mandibular anterior teeth accounted for 8.62%; and mandibular posterior teeth accounted for 18.97%; multiple sites accounted for 22.41%; eliminating residual subgingival calculus and granulation tissue were the main and most effective hemostatic methods, 86.21%. Conclusion Residual subgingival calculus or granulation tissue and severe gingival inflammation were the main causes of emergency gingival bleeding after nonsurgical periodontal therapy. Severe gingival inflammation causing emergency bleeding was more common in maxillary posterior teeth areas. Angular alveolar bone resorption was more likely to cause bleeding than horizontal resorption. Careful debridement of residual subgingival calculus and granulation tissue was the main hemostatic method.

Cone-beam computed tomography and digital model analysis of maxillary buccal alveolar bone thickness for vertical temporary skeletal anchorage device placement

This study aimed to quantify the buccal alveolar bone thickness (BABT) in the maxillary molar region to provide a practical guideline for vertical temporary skeletal anchorage device (TSAD) placement using cone-beam computed tomography (CBCT). It also aimed to develop a linear regression model for use in digital models to predict available BABT.The sample for this retrospective study consisted of 31 sites (24 patients; mean age, 28.75 years; range, 18-44 years) in which vertical TSADs were placed successfully in the maxillary posterior interradicular area during the total arch distalization procedure. BABT was measured at 3 points of the interradicular space using CBCT, and the buccal alveolar region thickness (BART), which included buccal-attached gingival thickness and the buccal alveolar bone, was measured using the digital model. In CBCT, BABT was measured at the most convex point of the lamina dura of the root adjacent to the vertical TSAD mesially, at the most convex point of the lamina dura of the root adjacent to the vertical TSAD distally, and the central point between the mesial and distal points. Three linear measurements were obtained at 2, 4, and 6 mm apical to the alveolar crest: the mesial thickness, the central thickness (centralCBCT), and the distal thickness. In the digital model, the most convex points of the clinical crowns of 2 teeth adjacent to vertical TSAD and their contact point along with the corresponding Will Andrews and Lawrence Andrews ridge were identified. The horizontal distance paralleling the model base was digitally measured and recorded at 3 positions: the mesial, central, and distal points. Then, the following 3 linear measurements were taken directly on each 3-dimensional dental model: the mesial thickness, the central thickness (centralModel), and the distal thickness.Both BABT and BART at the central position (centralCBCT, 3.44 mm; centralModel, 6.28 mm) were thicker than at the 2 exterior positions (mesial thickness, 2.16; distal thickness, 2.59 mm; mesial thickness, 2.74 mm; distal thickness, 2.99 mm). BABT was thinnest at 2 mm from the alveolar crest, and there was no statistically significant difference between 4 mm and 6 mm. There was a strong correlation between centralModel and centralCBCT.The mean BABT and BART at the central position, in which we suggest placing vertical TSADs, were 3.44 ± 0.69 mm in CBCT and 6.28 ± 1.11 mm in the digital model, respectively. The minimum BABT and BART at the central position in which vertical TSAD was placed successfully were 2.38 mm in CBCT and 4.25 mm in the digital model. There was a strong correlation between centralCBCT and centralModel, and we developed a linear regression model that resulted in a useful formula for estimating the actual available BABT at the central position: centralCBCT = 0.57 × centralModel - 0.15.

Clinical application of double-layer soft tissue closure technology based on pedicled buccal fat pad in repairing maxillary defects after medication-related osteonecrosis of jaw surgery.

This study aimed to analyze the clinical application effect of the double-layer soft tissue closure technique (DLST) based on pedicled buccal fat pad in repairing maxillary defects after medication-related osteonecrosis of the jaw (MRONJ) surgery. Ten patients with maxillary MRONJ were diagnosed and treated via DLST based on pedicled buccal fat pad. Partial maxillary resection was conducted to remove the MRONJ lesion, and the inflammatory soft tissue in the maxillary sinus cavity was removed but the maxillary sinus mucosa was retained. Patients also underwent resection of the lower segment of the sphenoid pterygoid process. A pedicled buccal fat pad was used to line the maxillary sinus floor and oral mucosa to achieve double-layer soft tissue closure of the wound. The characteristics of the medication for the primary disease, the clinical characteristics and imaging characteristics of osteonecrosis, the surgical treatment effects, pain score, and functional status evaluation of the 10 patients were all reviewed and analyzed. Among the 10 patients, there were 5 cases of breast cancer, 2 cases of lung cancer, 1 case of prostate cancer, 1 case of multiple myeloma, and 1 case of kidney cancer. All 10 patients received zoledronic acid, and the average time of application of zoledronic acid was 34 months. Six patients had upper jaw exposure, and 4 patients had gingival soft tissue fistula; the average time to clinical symptoms was 5.6 months. Among them, 5 patients had a history of tooth extraction, 3 patients with apical periodontitis, 1 patient with periodontitis, and 1 patient with spontaneous teeth loss. The lesions of 10 patients were all located in the maxillary posterior area. CT images can often show sequestration near the maxillary sinus floor, and the maxillary sinus cavity was full of soft tissue inflammation in most patients. During the follow-up period, 8 patients healed by the first intention, and the other patient had partial liquefaction of the buccal fat pad 2 weeks after the operation, and the oral mucosa fistula closed 1 month after the operation. In another patient, MRONJ symptoms recurred 2 months after the operation, and the surgical site occasionally swelled and discharged pus. The patient's symptoms were completely relieved after another operation. The patient's pain and functional status improved significantly after the operation. Maxillary MRONJ is commonly found in the posterior area. The buccal fat pad-based DLST is used to repair the defect after maxillary resection, which is beneficial to seal the oral-maxillary sinus fistula and improve the clinical symptoms of patients with MRONJ.

Feasibility study of cone-beam CT for the analysis of cortical bone thickness in the posterior area of the jaw bone

Objective: To investigate the feasibility of cone-beam CT (CBCT) in evaluating the thickness of cortical bone in jaw bone. Methods: Sixty patients [twenty-three for males and forty-seven for females, at an average age of (43.8±1.7) years] from Center of Stomatology, The First Affiliated Hospital of USTC & Anhui Provincial Hospital with 63 operational regions were included in the present study. Totally 63 bone sections from these areas were all selected at last. Case Viewer and oral dynamic system were used for the measurements in sections and CBCT graphs of the cortical bone thicknesses at alveolar ridges. Paired samples t test was performed to compare the difference between CBCT measurement and Case Viewer measurement. Results: The cortical bone thicknesses measured by Case Viewer were (1.20±0.75), (0.68±0.46) and (1.48±0.77) mm in the posterior, maxillary posterior and mandibular posterior areas, respectively. The cortical bone thicknesses measured by dynamic navigation software were (1.14±0.77), (0.64±0.24) and (1.41±0.83) mm in the posterior, maxillary posterior and mandibular posterior areas, respectively. There were no significant differences between either the two methods or the different areas (P>0.05). Conclusions: CBCT would be a useful equipment for the analysis of cortical bone thickness with a reliable and convincible accuracy.

Short Dental Implants (5 to 7 mm) with Expandable Apex in the Posterior Maxilla-Preliminary Results.

The purpose of this study was to examine whether the use of short dental implants with an expandable compressive design could be a proper alternative to the conventional sinus elevation procedure in cases of deficient alveolar ridge height in the posterior maxillary area. Fifty patients with 73 short dental implants with an expandable compressive design who were treated for posterior maxillary alveolar ridges of 5 to 7 mm in the vertical dimension between 2012 and 2018 were included in a retrospective study. All patients had a minimum postrehabilitation period of 1 year. Patient demographics, implant properties, primary stability, and implant success and survival rates were analyzed. The total success rate was 97.2%, with two failed implants at implant uncovering. The mean bone loss was 1.03 mm. No difference in bone loss was found between sexes or age groups. The results of this study suggest that short dental implants with an expandable apical compressive design could be an alternative to sinus elevation procedures in selected cases of vertically deficient maxillary alveolar ridges.

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.

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.

A Modified Transalveolar Sinus Floor Elevation Approach With a Bilaterally Enlarged Osteotomy.

Sinus floor elevation is the most commonly used method for vertical bone augmentation in the maxillary posterior area. This clinical report describes a modified transalveolar approach to elevate the Schneiderian membrane when placing implants on a severely resorbed maxillary posterior ridge with a buccal-palatal width of more than 8.0 mm. In this approach, the osteotomy prepared on the crestal is bilaterally enlarged to 8.0-10.0 mm. The enlarged osteotomies provide better access, allowing instruments to be in direct contact with the bone of the sinus floor and thus elevate the Schneiderian membrane with a reduced risk of perforation.

Biomechanical Evaluation of Different Implant-Abutment Connections, Retention Systems, and Restorative Materials in the Implant-Supported Single Crowns Using 3D Finite Element Analysis.

This is an in silico study aimed to evaluate the biomechanical influence of different implant-abutment interfaces (external hexagon and Morse taper implants), retention systems (cement and screw retained), and restorative crowns (metal-ceramic and monolithic) using 3-dimensional finite element analysis (3D-FEA). Eight 3D models were simulated for the maxillary first molar area using InVesalius, Rhinoceros, and SolidWorks and processed using Femap and NEi Nastran software. Axial and oblique forces of 200 and 100 N, respectively, were applied on the occlusal surface of the prostheses. Microstrain and von Mises stress maps were used to evaluate the deformation (cortical bone tissue) and stress (implants/fixation screws/crowns), respectively, for each model. For both loadings, Morse taper implants had lower microstrain values than the external hexagon implants. The retention system did not affect microstrain on the cortical bone tissue under both loadings. However, the cemented prosthesis displayed higher stress with the fixation screw than the external hexagon implants. No difference was observed between the metal-ceramic and zirconia monolithic crowns in terms of microstrain and stress distribution on the cortical bone, implants, or components. Morse taper implants can be considered as a good alternative for dental implant rehabilitation because they demonstrated better biomechanical behavior for the bone and fixation screw as compared to external hexagon implants. Cement-retained prosthesis increased the stress on the fixation screw of the external hexagon implants, thereby increasing the risk of screw loosening/fracture in the posterior maxillary area. The use of metal-ceramic or monolithic crowns did not affect the biomechanical behavior of the evaluated structures.