Advancing maxillofacial prosthodontics by using pre-trained convolutional neural networks: Image-based classification of the maxilla.

PURPOSE: The study aimed to compare the performance of four pre-trained convolutional neural networks in recognizing seven distinct prosthodontic scenarios involving the maxilla, as a preliminary step in developing an artificial intelligence (AI)-powered prosthesis design system. MATERIALS AND METHODS: Seven distinct classes, including cleft palate, dentulous maxillectomy, edentulous maxillectomy, reconstructed maxillectomy, completely dentulous, partially edentulous, and completely edentulous, were considered for recognition. Utilizing transfer learning and fine-tuned hyperparameters, four AI models (VGG16, Inception-ResNet-V2, DenseNet-201, and Xception) were employed. The dataset, consisting of 3541 preprocessed intraoral occlusal images, was divided into training, validation, and test sets. Model performance metrics encompassed accuracy, precision, recall, F1 score, area under the receiver operating characteristic curve (AUC), and confusion matrix. RESULTS: VGG16, Inception-ResNet-V2, DenseNet-201, and Xception demonstrated comparable performance, with maximum test accuracies of 0.92, 0.90, 0.94, and 0.95, respectively. Xception and DenseNet-201 slightly outperformed the other models, particularly compared with InceptionResNet-V2. Precision, recall, and F1 scores exceeded 90% for most classes in Xception and DenseNet-201 and the average AUC values for all models ranged between 0.98 and 1.00. CONCLUSIONS: While DenseNet-201 and Xception demonstrated superior performance, all models consistently achieved diagnostic accuracy exceeding 90%, highlighting their potential in dental image analysis. This AI application could help work assignments based on difficulty levels and enable the development of an automated diagnosis system at patient admission. It also facilitates prosthesis designing by integrating necessary prosthesis morphology, oral function, and treatment difficulty. Furthermore, it tackles dataset size challenges in model optimization, providing valuable insights for future research.

Frequently used extraoral maxillofacial prosthetic materials and their longevity - A comprehensive review.

The longevity of an extraoral prosthesis depends on its physical and mechanical properties and user maintenance. Faced with multiple outcome measures, researchers find it difficult to determine the most appropriate extraoral prosthetic material. This comprehensive review evaluates the most used extraoral prosthesis materials and qualitatively assesses their longevity and function. The study aims to identify and interpret the results of current updates on the factors that affect longevity and functionality. This comprehensive review summarizes and evaluates differences in the properties of commonly used extraoral maxillofacial prosthetic materials. The review was planned to focus on all factors related to the longevity and function of the extraoral maxillofacial prosthetics. An electronic search covered English articles in PubMed, Scopus, Google Scholar, Web of Science, and grey literature. Manual searching was also performed. Six authors participated in the screening. Search engines extracted 1107 records, and 88 studies were included for qualitative and bias assessments. Silicones are the most frequently used extraoral maxillofacial prosthetic materials. Heat-cured silicones are more color-stable than those cured at room temperature. Additional ingredients and processing techniques affect prosthesis longevity.

Applications and performance of artificial intelligence models in removable prosthodontics: A literature review.

PURPOSE: In this narrative review, we present the current applications and performances of artificial intelligence (AI) models in different phases of the removable prosthodontic workflow and related research topics. STUDY SELECTION: A literature search was conducted using PubMed, Scopus, Web of Science, and Google Scholar databases between January 2010 and January 2023. Search terms related to AI were combined with terms related to removable prosthodontics. Articles reporting the structure and performance of the developed AI model were selected for this literature review. RESULTS: A total of 15 articles were relevant to the application of AI in removable prosthodontics, including maxillofacial prosthetics. These applications included the design of removable partial dentures, classification of partially edentulous arches, functional evaluation and outcome prediction in complete denture treatment, early prosthetic management of patients with cleft lip and palate, coloration of maxillofacial prostheses, and prediction of the material properties of denture teeth. Various AI models with reliable prediction accuracy have been developed using supervised learning. CONCLUSIONS: The current applications of AI in removable prosthodontics exhibit significant potential for improving the prosthodontic workflow, with high accuracy levels reported in most of the reviewed studies. However, the focus has been predominantly on the diagnostic phase, with few studies addressing treatment planning and implementation. Because the number of AI-related studies in removable prosthodontics is limited, more models targeting different prosthodontic disciplines are required.

Combined digital-conventional workflow to fabricate a definitive obturator from an interim obturator for a patient with an anterior maxillectomy defect.

An existing interim obturator can be reproduced as the definitive one using digital technology, with benefits for a patient with a maxillectomy. By digitally scanning the oral condition and the existing interim obturator, a definitive obturator, including a computer-aided designed and computer-aided manufactured metal framework, was fabricated and delivered to a patient with an anterior maxillectomy defect by following a combined digital and conventional workflow. This technique can hasten the adaptation of the patient to the new obturator and ensure a more comfortable and safer clinical procedure.

Comparison of Praat and Computerized Speech Lab for formant analysis of five Japanese vowels in maxillectomy patients.

Introduction: Speech impairment is a common complication after surgical resection of maxillary tumors. Maxillofacial prosthodontists play a critical role in restoring this function so that affected patients can enjoy better lives. For that purpose, several acoustic software packages have been used for speech evaluation, among which Computerized Speech Lab (CSL) and Praat are widely used in clinical and research contexts. Although CSL is a commercial product, Praat is freely available on the internet and can be used by patients and clinicians to practice several therapy goals. Therefore, this study aimed to determine if both software produced comparable results for the first two formant frequencies (F1 and F2) and their respective formant ranges obtained from the same voice samples from Japanese participants with maxillectomy defects. Methods: CSL was used as a reference to evaluate the accuracy of Praat with both the default and newly proposed adjusted settings. Thirty-seven participants were enrolled in this study for formant analysis of the five Japanese vowels (a/i/u/e/o) using CSL and Praat. Spearman's rank correlation coefficient was used to judge the correlation between the analysis results of both programs regarding F1 and F2 and their respective formant ranges. Results: As the findings pointed out, highly positive correlations between both software were found for all acoustic features and all Praat settings. Discussion: The strong correlations between the results of both CSL and Praat suggest that both programs may have similar decision strategies for atypical speech and for both sexes. This study highlights that the default settings in Praat can be used for formant analysis in maxillectomy patients with predictable accuracy. The proposed adjusted settings in Praat can yield more accurate results for formant analysis of atypical speech in maxillectomy cases when the examiner cannot precisely locate the formant frequencies using the default settings or confirm analysis results obtained using CSL.

Refabrication of an implant-retained obturator using the denture duplication technique in a bilateral maxillectomy patient with a free fibula osteocutaneous flap.

PURPOSE: We aimed to introduce a simple method for refabrication of an implant-retained obturator using the denture duplication technique while retaining the custom abutments for a patient who underwent bilateral maxillectomy and reconstruction with a free fibula osteocutaneous flap. We have proposed this technique to facilitate the impression-making procedure for this extensive maxillary defect and to avoid lengthy and complicated laboratory procedures. METHODS: A custom tray was developed by duplicating the fitting surface of an old obturator using silicone putty. The tray was used for a bite-pressure impression wherein both definitive impression and jaw relation were obtained simultaneously, reducing the time required for the placement of a new obturator. CONCLUSIONS: We used the denture duplication technique to refabricate an implant-retained obturator while retaining the custom abutments. Decreased chairside time, fewer visits, the use of easily available materials, and uncomplicated laboratory procedures make this technique more economical and acceptable for patients. Using this approach, the patient was able to use the old prosthesis until the delivery of the new prosthesis. The replacement obturator that was developed using this method maintained an acceptable level of oral function.

Effect of cut-out rescan procedures on the accuracy of an intraoral scanner used for digitizing an ear model: An in vitro study.

PURPOSE: The purpose of this study was to evaluate the impact of the rescanning of mesh holes of different diameters on the accuracy of an intraoral scanner (IOS) used to digitize an ear model. MATERIALS AND METHODS: An ear model was digitized using an intraoral scanner (Medit i500) to obtain a reference mesh. A baseline experimental scan was created by editing a duplicate of the reference mesh using the cut-out tool of the IOS software. Three equal groups were created based on the diameter of the cut-out areas: 2 mm (G1), 5 mm (G2), and 8 mm (G3) (n = 15). The cut-out areas were rescanned and a total of 45 digital files were exported. The discrepancy between the reference and the experimental digital scans was measured using the root mean square calculation (RMS). The data were analyzed by a Kruskal-Wallis test followed by a post hoc Dunn's test with Bonferroni correction. RESULTS: The trueness values ranged from 19.53 to 27.13 µm. There were significant differences in the RMS error values among the groups tested (p < 0.001) and post hoc multiple comparisons showed significant differences between the G1 and G2 groups (p = 0.04), G1 and G3 groups (p < 0.001), and G2 and G3 groups (p = 0.004). Overall, the precision values ranged from 4.93 to 7.73 µm and significant differences in the RMS values were only found between the G1 and G2 groups (p = 0.014). CONCLUSIONS: Mesh hole rescanning affected the scanning accuracy (trueness and precision) of the IOS tested. The larger the diameter of the mesh holes, the less the trueness of the IOS tested. The precision values seemed to be less affected compared with the trueness by the cut-out and rescanning procedures.

An indirect-direct technique with hot water for fabricating a cast metal crown under an existing removable partial denture.

Fracture or carious lesions in an abutment tooth may require the fabrication of a crown under an existing removable partial denture. Typically, once the crown has been fabricated, the prosthesis will need to be modified or refabricated. However, if the partial denture is in good clinical condition, special techniques may be applied to make the new crown fit the existing prosthesis. This article describes a straightforward indirect-direct technique for fabricating a cast metal crown under an existing removable partial denture with hot water. The technique does not require expertise or any special device and can be performed chairside by general dentists.

Two-piece detachable interlocking mold for low-dose-rate brachytherapy: A dental technique for radiotherapy prosthesis fabrication.

Brachytherapy is a type of radiotherapy used to eradicate malignancies in the head-and-neck region. Early-stage mucosal carcinomas, such as carcinomas of the hard palate and gingival mucosa, can be treated with low-dose-rate brachytherapy by using a radiotherapy prosthesis called a mold. Prosthodontists play a significant role in the design and fabrication of these molds, which deliver therapeutic doses to the primary lesion and protect adjacent tissues from radiation exposure. However, planning and observing ongoing treatment is difficult for radiation oncologists because the shield part cannot be removed from the carrier part or requires an attachment to do so. This article describes a technique for fabricating a 2-piece detachable interlocking mold without any special attachment for low-dose-rate brachytherapy.

The rising challenge of mucormycosis for maxillofacial prosthodontists in the Covid-19 pandemic: A literature review.

PURPOSE: This review examines the importance of prosthetic rehabilitation after surgical treatment of mucormycosis in the context of expected increases in cases during the current COVID-19 pandemic. STUDY SELECTION: Google Scholar, Web of Science, Scopus, and PubMed databases were searched for relevant articles published between 2010 and 2021. Articles that provided a full description of prosthetic treatment after surgical treatment of mucormycosis were included in the review. RESULTS: Out of 30 articles describing orofacial prosthetic rehabilitation after surgical treatment of mucormycosis published during the 12-year target period, 19 reported patients with diabetes, two described mucormycosis as a post-COVID-19 complication, and 25 were reports from India. Most of the prosthetic treatments used a definitive obturator (63.3%) either alone or in combination with other forms of prosthetic rehabilitation. Other prosthetic strategies included an orbital prosthesis (26.6%), a facial prosthesis with or without a nasal replacement (16.6%), a surgical or interim obturator, a conventional complete denture, and a cast partial denture. Six articles (20%) mentioned the use of combined prosthetic rehabilitation involving multiple regions of the face and oral cavity. CONCLUSION: Prosthetic rehabilitation after surgical treatment of mucormycosis is essential for the early restoration of oral function and facial esthetics. Given the aggressive nature of mucormycosis and the increasing number of cases reported during the COVID-19 pandemic, prosthodontists need to share their experiences with prosthetic rehabilitation of the defects that result from this disease to improve patients' quality of life.

Medication-related osteonecrosis of the jaw: Prosthodontic considerations.

Medication-related osteonecrosis of the jaw (MRONJ) can be triggered by several antiresorptive and antiangiogenic medications, including bisphosphonates (BRONJ), denosumab (DRONJ), and other agents used to treat osteoporosis and metastatic bone cancer. Prosthodontists and surgeons continue to face new challenges because of this condition. Despite the current evidence showing that extensive surgical intervention and laser surgery have the highest healing rates, surgical reconstruction is not always possible for large jaw defects requiring prosthetic reconstruction. Moreover, surgical treatment may not be an option in some patients because of other medical conditions. In these patients, MRONJ may develop into a chronic disease with limited resolution and they may seek prosthetic rehabilitation for aesthetic and functional reasons. Therefore, prosthetic intervention may be necessary for some patients with MRONJ even in the absence of a surgical defect. Denture trauma has been reported to be a risk factor for MRONJ, and few reports have discussed the prosthodontic considerations needed for patients with this condition. The aim of this review is to highlight the prosthodontic considerations that would decrease the risk of triggering MRONJ in susceptible patients.