The Ball Welding Bar: A New Solution for the Immediate Loading of Screw-Retained, Mandibular Fixed Full Arch Prostheses.
ABSTRACT: To present a new intraoral welding technique, which can be used to manufacture screw-retained, mandibular fixed full-arch prostheses.Over a 4-year period, all patients with complete mandibular edentulism or irreparably compromised mandibular dentition, who will restore the masticatory function with a fixed mandibular prosthesis, were considered for inclusion in this study. The "Ball Welding Bar" (BWB) technique is characterised by smooth prosthetic cylinders, interconnected by means of titanium bars which are adjustable in terms of distance from ball terminals and are inserted in the rotating rings of the cylinders. All the components are welded and self-posing.Forty-two patients (18 males; 24 females; mean age 64.2 ± 6.7 years) were enrolled and 210 fixtures were inserted to support 42 mandibular screw-retained, fixed full-arch prostheses. After two years of loading, 2 fixtures were lost, for an implant survival rate of 97.7%. Five implants suffered from peri-implant mucositis and 3 implants for peri-implantitis. Three of the prostheses (3/42) required repair for fracture (7.1%): the prosthetic success was 92.9%.The BWB technique seems to represent a reliable technique for the fabrication of screw-retained mandibular fixed full-arch prostheses. This study was registered in the ISRCTN register with number ISRCTN71229338.
Project description:BACKGROUND:The aim of this three-year prospective study was to examine the outcome of a solution for full-arch rehabilitation through a fixed implant-supported hybrid prosthesis (polyetheretherketone (PEEK)-acrylic resin) used in conjunction with the All-on-4 concept. METHODS:Thirty-seven patients (29 females, 8 males), with an age range of 38 to 78 years (average: 59.8 years) were rehabilitated with 49 full-arch implant-supported prostheses (12 maxillary rehabilitations, 13 mandibular rehabilitations and 12 bimaxillary rehabilitations). The primary outcome measure was prosthetic survival. Secondary outcome measures were marginal bone loss, plaque and bleeding scores, veneer adhesion issues, biological complications, mechanical complications, and the patients' subjective evaluation. RESULTS:There were two patients (maxillary rehabilitations) lost to follow-up, while one patient withdrew (maxillary rehabilitation). One patient with bimaxillary rehabilitation fractured the mandibular PEEK framework, rendering a 98% prosthetic survival rate. Implant survival was 100%. Average (standard deviation) marginal bone loss at 3-years was 0.40 mm (0.73 mm). Veneer adhesion was the only technical complication (n = 8 patients), resolved for all patients. Nine patients (n = 11 prostheses) experienced mechanical complications (all resolved): fracture of acrylic resin crowns (n = 3 patients), prosthetic and abutment screw loosening (n = 4 patients and 3 patients, respectively), abutment wearing (n = 1 patient). One patient experienced a biological complication (peri-implant pathology), resolved through non-surgical therapy. A 90% satisfaction rate was registered for the patients' subjective evaluation. CONCLUSIONS:Based on the results, the three-year outcome suggests the proposed rehabilitation solution as a legitimate treatment option, providing a potential shock-absorbing alternative that could benefit the implant biological outcome.
Project description:The current study aimed to evaluate the mechanical behavior of two different maxillary prosthetic rehabilitations according to the framework design using the Finite Element Analysis. An implant-supported full-arch fixed dental prosthesis was developed using a modeling software. Two conditions were modeled: a conventional casted framework and an experimental prosthesis with customized milled framework. The geometries of bone, prostheses, implants and abutments were modeled. The mechanical properties and friction coefficient for each isotropic and homogeneous material were simulated. A load of 100 N load was applied on the external surface of the prosthesis at 30° and the results were analyzed in terms of von Mises stress, microstrains and displacements. In the experimental design, a decrease of prosthesis displacement, bone strain and stresses in the metallic structures was observed, except for the abutment screw that showed a stress increase of 19.01%. The conventional design exhibited the highest stress values located on the prosthesis framework (29.65 MPa) between the anterior implants, in comparison with the experimental design (13.27 MPa in the same region). An alternative design of a stronger framework with lower stress concentration was reported. The current study represents an important step in the design and analysis of implant-supported full-arch fixed dental prosthesis with limited occlusal vertical dimension.
Project description:The aim of this systematic review was to analyze post-loading implant loss for implant-supported prostheses in edentulous jaws, regarding a potential impact of implant location (maxilla vs. mandible), implant number per patient, type of prosthesis (removable vs. fixed), and type of attachment system (screw-retained, ball vs. bar vs. telescopic crown).A systematic literature search for randomized-controlled trials (RCTs) or prospective studies was conducted within PubMed, Cochrane Library, and Embase. Quality assessment of the included studies was carried out, and the review was structured according to PRISMA. Implant loss and corresponding 3- and 5-year survival rates were estimated by means of a Poisson regression model with total exposure time as offset.After title, abstract, and full-text screening, 54 studies were included for qualitative analyses. Estimated 5-year survival rates of implants were 97.9% [95% CI 97.4; 98.4] in the maxilla and 98.9% [95% CI 98.7; 99.1] in the mandible. Corresponding implant loss rates per 100 implant years were significantly higher in the maxilla (0.42 [95% CI 0.33; 0.53] vs. 0.22 [95% CI 0.17; 0.27]; P = 0.0001). Implant loss rates for fixed restorations were significantly lower compared to removable restorations (0.23 [95% CI 0.18; 0.29] vs. 0.35 [95% CI 0.28; 0.44]; P = 0.0148). Four implants and a fixed restoration in the mandible resulted in significantly higher implant loss rates compared to five or more implants with a fixed restoration. The analysis of one implant and a mandibular overdenture also revealed higher implant loss rates than an overdenture on two implants. The same (lower implant number = higher implant loss rate) applied when comparing 2 vs. 4 implants and a mandibular overdenture. Implant loss rates for maxillary overdentures on <4 implants were significantly higher than for four implants (7.22 [95% CI 5.41; 9.64] vs. 2.31 [1.56; 3.42]; P < 0.0001).Implant location, type of restoration, and implant number do have an influence on the estimated implant loss rate. Consistent reporting of clinical studies is necessary and high-quality studies are needed to confirm the present results.
Project description:This article describes the arch plate technique for treating lumbosacral tuberculosis. Lumbosacral tuberculosis often leads to the destruction of anterior vertebral columns and presacral or iliopsoas abscess, which requires an anterior approach to achieve thorough debridement. Due to the complexity of the anatomical structure of lumbosacral spine and the high requirement of fixation stability, a combined posterior approach to perform internal fixation is necessary, which is rather traumatic. On the other hand, most of the current anterior lumbosacral internal fixation systems cannot be applied to spinal tuberculosis patients who have irregular bony endplate destruction. The arch plate was designed as a cephalic narrow and caudal wide trapezoid or triangle outline according to the preliminary anatomic research. In terms of the endplate bony destruction, a multidirectional technique was introduced in the arch screws, which enables surgeons to arbitrarily change the direction of the screw in the range of 5°-20°, which increases the length and the inclination angles in the sagittal plane of the implant screw and makes sure that the autologous iliac bone graft fits the irregular bone destruction for maximum stability. This study demonstrated the effectiveness of one-stage anterior debridement, bone grafting, and arch plate fixation to treat lumbosacral tuberculosis. The risk of intraoperative and postoperative complications, such as injury to major vessels, could be minimized. This surgical procedure had many advantages, including a shorter operation time, less blood loss, and better functional recovery over the conventional combined anterior and posterior approach.
Project description:Extensive defects of the ear require satisfactory cosmetic reconstruction to enable the patient to achieve full social integration. Although surgical procedures are the gold standard for reconstruction of the ear, in some cases they cannot be performed because of extended scars, threatening tumor, or congenital tissue abnormalities. Prosthetic reconstruction of the auricle is an established and reliable alternative technique to autologous surgical reconstructions. Since studies performed by Brånemark, osseointegrated implants have been widely used to provide a reliable and stable anchorage for a prosthesis (prosthesis anchored to bone). To allow good osseointegration of the titanium screw implants, two stages are necessary. After careful preparation for the surgical procedure (local and general examination, computed tomography scan, skin preparation), screws are implanted into bone, which are then covered by a skin flap. During the second stage, the skin is incised, and penetrating fixtures are attached to the screw implants, which allow fixation of the prosthesis. This procedure is reliable and reproducible, with good to excellent results and stability over time.
Project description:Objective:To describe a clinical case with a severe mandibular crowding treated without extraction and showing a long-term outcome. Methods:A 14-year-old boy in permanent dentition showed a class I molar and cuspid relationship, a severe deep bite of 8?mm, a constricted V-shaped upper arch with moderate crowding, and a severe crowding of about 12?mm in the lower arch. The panoramic X-ray showed an impacted upper right canine. The treatment started with the placement of a transpalatal bar and 0.022 × 0.028 in standard edgewise appliances in the upper arch and a lip bumper bonded on the second lower molars. Initial leveling of the teeth was accomplished with light Australian round wires. Finishing was then performed with rectangular wires. The phase with fixed appliances lasted 2 years and 9 months, and the patient was motivated and cooperative throughout the treatment, although with poor oral hygiene. The patient was treated without extractions. Results:The space was gained with the first and second upper molar derotations using the transpalatal bar and the gingival lip bumper in the lower arch. The upper right canine was well positioned, and the maxillary arch form was improved. The severe lower crowding was completely corrected, and a good overbite was achieved. Conclusion:A conservative, nonextraction treatment approach for this patient with class I malocclusion with severe mandibular crowding was effective, and the results have remained stable after a long-term follow-up (10 years).
Project description:<h4>Background</h4>Funnel technique is a method used for the insertion of screw into thoracic pedicle.<h4>Aim</h4>To evaluate the biomechanical characteristics of thoracic pedicle screw placement using the Funnel technique, trying to provide biomechanical basis for clinical application of this technology.<h4>Methods</h4>14 functional spinal units (T6 to T10) were selected from thoracic spine specimens of 14 fresh adult cadavers, and randomly divided into two groups, including Funnel technique group (n = 7) and Magerl technique group (n = 7). The displacement-stiffness and pull-out strength in all kinds of position were tested and compared.<h4>Results</h4>Two fixed groups were significantly higher than that of the intact state (P < 0.05) in the spinal central axial direction, compression, anterior flexion, posterior bending, lateral bending, axial torsion, but there were no significant differences between two fixed groups (P > 0.05). The mean pull-out strength in Funnel technique group (789.09 ± 27.33) was lower than that in Magerl technique group (P < 0.05).<h4>Conclusions</h4>The Funnel technique for the insertion point of posterior bone is a safe and accurate technique for pedicle screw placement. It exhibited no effects on the stiffness of spinal column, but decreased the pull-out strength of pedicle screw. Therefore, the funnel technique in the thoracic spine affords an alternative for the standard screw placement.
Project description:OBJECTIVE:To compare the accuracy of complete-arch scans and quadrant scans obtained using a direct chairside intraoral scanner. MATERIAL AND METHODS:Intraoral scans were obtained from 20 adults without missing teeth except for the third molar. Maxillary and mandibular complete-arch scans were carried out, and 4 quadrant scans for each arch were performed to obtain right posterior, right anterior, left anterior, and left posterior quadrant scans. Complete-arch scans and quadrant scans were compared with corresponding model scans using best-fit surface-based registration. Shell/shell deviations were computed for complete-arch scans and quadrant scans and compared between the complete-arch scans and each quadrant scans. In addition, shell/shell deviations were calculated also for each individual tooth in complete-arch scans to evaluate factors which influence the accuracy of intraoral scans. RESULTS:Complete-arch scans showed relatively greater errors (0.09 ~ 0.10 mm) when compared to quadrant scans (0.05 ~ 0.06 mm). The errors were greater in the maxillary scans than in the mandibular scans. The evaluation of errors for each tooth showed that the errors were greater in posterior teeth than in anterior teeth. Comparing the right and left errors, the right side posterior teeth showed a more substantial variance than the left side in the mandibular scans. CONCLUSION:The scanning accuracy has a difference between complete-arch scanning and quadrant scanning, particularly in the posterior teeth. Careful consideration is needed to avoid scanning inaccuracy for maxillary or mandibular complete-arch, particularly in the posterior area because a complete-arch scan might have potential error than a quadrant scan.
Project description:Fusion of branchial arch derivatives is an essential event in the development of craniofacial architecture. A unique feature of the mandibular arch development is medial/lateral compartmentalization for the molecular networks. Those networks give rise to multiple region-specific organs, namely teeth, a tongue, salivary glands, and the supporting matrices such as bones and cartilages. We aimed to investigate molecular networks that govern the fusion process during mouse mandibular development. To this end, cDNA microarray technology was employed for screening of spatio-temporal gene expression in developing mandibular arch from E9.7 through E11.5. We conducted to divide a mandibular arch medially and laterally to compare both gene expression. From an embryo at E10.5, a medial (M) sample of the mandibular arch was dissected out -at just the distal end of opposed lateral lingual swellings-, and the bulk of remnant lateral region was collected as (L) sample under a stereomicroscope. Forty embryos for each time-point were used to obtain a pool of total RNA.