Retention of implant retained obturator using two implant placement configurations for maxillectomy cases: in-vitro study.

BACKGROUND: Implant-retained obturators for maxillectomy cases have several advantages over traditional obturators but prosthetic design for specific conditions after maxillary resection has several challenges and the appropriate implant placement configuration is essential for improving retention and the stability of the implant-retained obturator. OBJECTIVES: The present study aimed to assess the retention force of using linear and nonlinear implant placement configurations using ball and socket attachment in implant-retained obturators at the initial retention and after simulation of six months of use. MATERIALS AND METHODS: Two identical epoxy resin maxillary models of a completely edentulous unilateral maxillary defect (Brown's class IIb) were used for implant placement, in the first model three implants were arranged with linear placement configuration, and in the second model three implants were arranged in nonlinear placement configuration. For proper sample sizing, 26 models and obturator were used. Two equal groups of obturators (13 for each group) were constructed, each with a different implant placement configuration. Both groups used the same attachment design (a non-splinted ball attachment). Using a cyclic loading machine that served as a dental insertion and removal simulator, each study group was subjected to 500 tension-compression cycles simulating 6 months of use. Using the universal testing machine, each obturator was removed at a speed of 50 mm/min for the crosshead. peak load to dislodgement was measured at the initial retention and after the simulations of six months of use. Data were analyzed using independent and paired t-tests while percent change was analyzed using the Mann Whitney U test. RESULTS: There were a statistically significant differences in retention between the nonlinear implant placement configuration for Brown's class IIb maxillectomy and the linear implant placement configuration at initial retention evaluation with p-value of < 0.0001 and after simulation of six months of usage with p-value of < 0.0001 Also, after simulation of 6 months of use group I lose - 24.87 (10.16) % of its retention while group II lose - 17.49 (7.78) %. CONCLUSIONS: Non-linear implant placement is more retentive at the initial retention and after simulation of six months of use than linear and loses less retention after usage.

Immediate rehabilitation of a palatal defected edentulous patient by implant-supported overdenture: a case report.

BACKGROUND: Immediate rehabilitation is a considerable therapeutic challenge but is necessary for edentulous patients with oronasal fistulas, especially those with inadequate residual bone and a history of radiotherapy. CASE PRESENTATION: We report a rare case of a 63-year-old patient who was missing the majority of his maxillary teeth and who had a defect due to palatal mucoepidermoid carcinoma resection. The patient also received radiotherapy twice within one year postoperatively. An implant-supported prosthesis with an obturator was fabricated immediately. CONCLUSION: This technique improved patients' oral function, enhanced the aesthetic effect, and increased their confidence.

Tissue surface adaptation and retention of digital obturator after one year of use.

BACKGROUND: Effect of aging on tissue adaptability and retention of digital obturator is still under investigation. METHODS: A maxillary Armany (class I) epoxy reference model was scanned to fabricate digital obturator fabricated from milled Co-Cr framework and 3D printed bulb. A color map of the scanned reference and digital obturator was made using Geomagic software to evaluate the accuracy of fit before and after cyclic loading using ROBOTA chewing simulator at 37,500, 75,000 and 150,000 cycles to simulate clinically 3-, 6- and 12-months chewing condition. Insertion-removal condition simulating the placement and removal of the obturator was done using repeated 360, 720 and 1440 cycles and retention was evaluated before and after the repeated cycles. Data were collected, tabulated and statistically analyzed using Statistical Package for Social Sciences (IBM SPSS Statistics 26). Student t-test and multi variable ANOVA test were used to detect significance. P-value < 0.05 was considered significant difference. RESULTS: For retention test: There was a significant difference between baseline and 3, 6 and12 months. For the tissue surface adaptation test: There was significant difference at all measured areas (P-value < 0.05) before and after application of load. CONCLUSION: digitally designed and fabricated obturator was highly retentive and has excellent tissue surface adaptation upon fabrication, After application of load; reduction of retention and lack of tissue adaptation were resulted. THE CLINICAL IMPLICATION: of this manuscript is that digital obturator can be used successfully with the shortcomings of loosening retention and adaptation afterwhile. So, clinical trials should investigate the clinical acceptance of these shortcomings.

Combination of CAD/CAM technologies and conventional processing in the fabrication of a maxillary obturator prosthesis: a clinical report.

Soft and hard tissue defects resulting from resective surgeries for carcinomas located in the maxillary arches can cause functional, esthetic, and psychological damage. A removable obturator prosthesis offers several advantages, restoring oral functions and improving patients' quality of life. Technological advancements, such as the use of intraoral scanning and computer-aided design (CAD) and manufacturing, reduce laboratory working time, eliminate the risk of impression material aspiration, and address challenges related to whole tissue undercut impression. Here, we report the case of a partially edentulous female patient with a velo-palatal defect for whom a rigid maxillary obturator prosthesis was fabricated. Digital impressions were taken and the standard tessellation language files of the scans were sent to the laboratory. Using dental CAD software, the maxillary metallic framework was designed and manufactured using selective laser melting technology. The obturators and artificial teeth were conventionally processed, with acrylic resin used for the rigid obturators. The resulting obturator prosthesis made it possible to close the oro-nasal communication and to improve swallowing, speaking, and chewing.

A multi-centric, single-blinded, randomized, parallel-group study to evaluate the effectiveness of nasoalveolar moulding treatment in non-syndromic patients with complete unilateral cleft lip, alveolus and palate (NAMUC study): a study protocol for a randomized controlled trial.

BACKGROUND: Cleft lip and palate (CLP) are among the most common congenital anomaly that affects up to 33,000 newborns in India every year. Nasoalveolar moulding (NAM) is a non-surgical treatment performed between 0 and 6 months of age to reduce the cleft and improve nasal aesthetics prior to lip surgery. The NAM treatment has been a controversial treatment option with 51% of the cleft teams in Europe, 37% of teams in the USA and 25 of cleft teams in India adopting this methodology. This treatment adds to the already existing high burden of care for these patients. Furthermore, the supporting evidence for this technique is limited with no high-quality long-term clinical trials available on the effectiveness of this treatment. METHOD: The NAMUC study is an investigator-initiated, multi-centre, single-blinded randomized controlled trial with a parallel group design. The study will compare the effectiveness of NAM treatment provided prior to lip surgery against the no-treatment control group in 274 patients with non-syndromic unilateral complete cleft lip and palate. The primary endpoint of the trial is the nasolabial aesthetics measured using the Asher McDade index at 5 years of age. The secondary outcomes include dentofacial development, speech, hearing, cost-effectiveness, quality of life, patient perception, feeding and intangible benefits. Randomization will be carried out via central online system and stratified based on cleft width, birth weight and clinical trial site. DISCUSSION: We expect the results from this study on the effectiveness of treatment with NAM appliance in the long term along with the cost-effectiveness evaluation can eliminate the dilemma and differences in clinical care across the globe. TRIAL REGISTRATION: ClinicalTrials.gov CTRI/2022/11/047426 (Clinical Trials Registry India). Registered on 18 November 2022. The first patient was recruited on 11 December 2022. CTR India does not pick up on Google search with just the trial number. The following steps have to be carried out to pick up. How to search: ( https://ctri.nic.in/Clinicaltrials/advsearch.php -use the search boxes by entering the following details: Interventional trial > November 2022 > NAMUC).

Prosthetic rehabilitation of patients with maxillary oncology defects using zygomatic implants.

PURPOSE: Prosthetics for patients after oncological resection of the upper jaw is a complex problem associated with the physiological and anatomical separation of the oral cavity and the nasal/paranasal region. This study reports the clinical results of the use of the zygomatic implants for prosthetic rehabilitation in patients with maxillectomy due to upper jaw tumors. MATERIALS AND METHODS: The study included 16 patients who underwent prosthetic rehabilitation using a zygomatic implant after maxillectomy period from 2021 to 2023. After the tumor was removed, immediate surgical obturators were placed. Main prosthetic rehabilitation was performed 6-12 months after tumor removal, but before that, a temporary obturator was made and used. Six-twelve months after tumor resection, 1-4 zygomatic implants were inserted into the zygomatic bone unilaterally or bilaterally. A total of 42 zygomatic implants were installed, 2 of which were unsuccessful and were removed in 1 patient. The implants were placed using the surgical guide, which was planned and prepared digitally. RESULTS: No postsurgical complications were seen, and the patients were discharged from the hospital after 7-10 days. The patients were able to return to a normal diet (hard food) after just 7 days following surgery, with no further complaints regarding function or pain, apart from the residual edema caused by the intervention. CONCLUSIONS: The use of prostheses fixed on zygomatic implants in patients with maxillary defects is an effective method of prosthodontic rehabilitation in complex clinical cases after maxillectomy.

Dental Versus Zygomatic Implants in the Treatment of Maxillectomy: A Finite Element Analysis.

This study analyzed the stress distributions on zygomatic and dental implants placed in the zygomatic bone, supporting bones, and superstructures under occlusal loads after maxillary reconstruction with obturator prostheses. A total of 12 scenarios of 3-dimensional finite element models were constructed based on computerized tomography scans of a hemimaxillectomy patient. Two obturator prostheses were analyzed for each model. A total force of 600 N was applied from the palatal to buccal bones at an angle of 45°. The maximum and minimum principal stress values for bone and von Mises stress values for dental implants and prostheses were calculated. When zygomatic implants were applied to the defect area, the maximum principal stresses were similar in intensity to the other models; however, the minimum principal stress values were higher than in scenarios without zygomatic implants. In models that used zygomatic implants in the defect area, von Mises stress levels were significantly higher in zygomatic implants than in dental implants. In scenarios where the prosthesis was supported by tissue in the nondefect area, the maximum and minimum principal stress values on cortical bone were higher than in scenarios where implants were applied to defect and nondefect areas. In patients who lack an alveolar crest after maxillectomy, a custom bar-retained prosthesis placed on the dental implant should reduce stress on the zygomatic bone. The stress was higher on zygomatic implants without alveolar crest support than on dental implants.

Influence of different designs of bulb support structures on the accuracy and weight of 3D printed maxillary obturators. An in vitro study.

STATEMENT OF PROBLEM: Evidence is lacking on the influence of different designs of bulb support structures on the accuracy of 3-dimensional (3D) printed obturators. PURPOSE: The purpose of this in vitro study was to evaluate the influence of various infill designs (hollow, honeycomb, and gyroid) for the bulb of an obturator on the accuracy and weight of digital light projection (DLP) 3D printed maxillary obturators. MATERIAL AND METHODS: A maxillary obturator was virtually designed and used to obtain 3 digital reference files which were defined based on the design of the infill support structure within the bulb: hollow, honeycomb, and gyroid. The resultant standard tessellation language (STL) files were used to fabricate the obturators using a DLP 3D-printer in FREEPRINT denture resin material (n=10 per each group design). The fitting surfaces of all printed specimens (n=30) were digitized using a laboratory scanner, and the scan STL files were exported to the Geomagic control X program for dimensional accuracy analysis (trueness and precision) using the digital subtraction technique. One-way analysis of variance (ANOVA) was used for analysis (α=.05) RESULTS: Quantitative analysis revealed no significant difference in root mean square estimate (RMSE) values among the test groups for trueness (P=.326) and precision (P=.140). Hollow bulb design was significantly lighter in weight than both honeycomb and gyroid infill designs (P<.001). Colormaps revealed increased areas of negative deviation around the circumference of the bulb wall in the hollow design compared with both the gyroid and honeycomb groups and the close surface matching of fitting surfaces in the 3 groups. CONCLUSIONS: The lack of significant difference in accuracy among the tested groups and the significantly lighter hollow design obturator compared with honeycomb and gyroid designs favors the selection of the hollow bulb design in the digital fabrication of maxillary obturators.

Tratamento reabilitador com prótese obturadora em paciente acometido por maxilectomia parcial: relato de caso / Rehabilitative treatment with obturator prosthesis in a patient suffering from partial maxillectomy: case report

Introdução: O tratamento de tumores malignos ou benignos, podem resultar em procedimentos cirúrgicos, como a maxilectomia parcial ou total, gerando comunicação bucosinusal nos pacientes. Uma forma de resolver estas alterações maxilofaciais é através do tratamento reabilitador com próteses obturadoras a fim de restabelecer a função mastigatória, estética, fonética e psicológica. Objetivo: o objetivo deste trabalho foi relatar o caso clínico de um paciente oncológico que foi reabilitado com prótese obturadora devido à maxilectomia por neoplasia maligna de seio maxilar. Relato de caso: Paciente de 62 anos, sexo masculino, procurou atendimento odontológico no Centro de Oncologia Bucal da Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP) de Araçatuba ­ SP após a realização de uma maxilectomia parcial com comunicação bucosinusal e foi encaminhado para o Curso de Especialização em Prótese Dentária da Faculdade de Odontologia ­ Unesp/Araçatuba-SP para a reabilitação. Foi proposto, primeiramente a realização da prótese obturadora para fechar a comunicação bucosinusal e uma prótese total inferior para o arco antagonista e, posteriormente, a realização de uma prótese facial. Conclusão: O tratamento reabilitador com próteses obturadoras possui um bom resultado estético e funcional, favorecendo uma melhor função mastigatória e fonética, e melhorando consideravelmente a condição psicológica que é muito afetada nos pacientes submetidos a maxilectomia total ou parcial, sendo necessário uma boa interação com toda a equipe multiprofissional envolvida para que haja um melhor tratamento integrado para a reabilitação e melhora da qualidade de vida(AU)

Introduction: The treatment of malignant or benign tumors can result in surgical procedures, such as partial or total maxillectomy, generating oral communication in patients. One way to resolve these maxillofacial changes is through rehabilitative treatment with obturator prostheses in order to reestablish masticatory, aesthetic, phonetic and psychological function. Objective: the objective of this work was to report the clinical case of a cancer patient who was rehabilitated with an obturator prosthesis due to maxillectomy for malignant neoplasia of the maxillary sinus. Case report: A 62-year-old male patient sought dental care at the Oral Oncology Center of the Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP) in Araçatuba ­ SP after undergoing a partial maxillectomy with oral cavity and was referred for the Specialization Course in Dental Prosthesis at the Faculty of Dentistry ­ Unesp/Araçatuba-SP for rehabilitation. It was proposed, firstly, to create an obturator prosthesis to close the bucosinusal communication and a total lower prosthesis for the antagonistic arch and, later, to create a facial prosthesis. Conclusion: Rehabilitative treatment with obturator prostheses has a good aesthetic and functional result, favoring better chewing and phonetic function, and considerably improving the psychological condition that is greatly affected in patients undergoing total or partial maxillectomy, requiring good interaction with the entire the multidisciplinary team involved so that there is better integrated treatment for rehabilitation and improved quality of life