The role of non-contact digitizer in geometrical evaluation of mandibular prostheses effect on facial asymmetry of mandibulectomy patients

Purpose: This study sought to geometrically evaluate the effect of a mandibular prosthesis on facial asymmetry in patients with one of two different types of mandibulectomy defect. Methods: Facial data from 20 participants (9 men and 11 women; mean age 68 years) with either a reconstructed segmental defect (segmental group,n = 10) or a marginal mandibulectomy defect (marginal group, n =10) were acquired with a non-contact three-dimensional (3D) digitizer. Facial asymmetry was evaluated by superimposing a facial scan onto its mirror scan using 3D evaluation software. Facial scans with and without the mandibular prosthesis in place were also superimposed to evaluate the effect of the mandibular prosthesis. Results: Facial asymmetry differed significantly between subjects with and without the prosthesis in the segmental group (P = 0.005) but not in the marginal group (P = 0.16). There was no significant difference in the effect of the prosthesis on facial appearance between the two groups (P = 0.052). The ratio of 3D deviation of facial asymmetry without the prosthesis and in the mirror scan with the prosthesis differed significantly between the two groups (P = 0.01). Conclusions: Placement of a mandibular prosthesis has a notable effect on facial asymmetry in patients with segmental mandibulectomy defects

Measurement of Voice Onset Time in Maxillectomy Patients

Objective speech evaluation using acoustic measurement is needed for the proper rehabilitation of maxillectomy patients. For digital evaluation of consonants, measurement of voice onset time is one option. However, voice onset time has not been measured in maxillectomy patients as their consonant sound spectra exhibit unique characteristics that make the measurement of voice onset time challenging. In this study, we established criteria for measuring voice onset time in maxillectomy patients for objective speech evaluation. We examined voice onset time for /ka/ and /ta/ in 13 maxillectomy patients by calculating the number of valid measurements of voice onset time out of three trials for each syllable. Wilcoxon’s signed rank test showed that voice onset time measurements were more successful for /ka/ and /ta/ when a prosthesis was used (Z=−2.232, P=0.026 and Z=−2.401, P=0.016, resp.) than when a prosthesis was not used. These results indicate a prosthesis affected voice onset measurement in these patients. Although more research in this area is needed, measurement of voice onset time has the potential to be used to evaluate consonant production in maxillectomy patients wearing a prosthesis

Effect of A Lingual Augmentation Prosthesis for Preventing Salivation After Subtotal Glossectomy: A Clinical Report

A lingual augmentation prosthesis (LAP) is an appliance attached to the mandible to increase swallowing by extending the denture base area. It has been proven that the swallowing function improves with the insertion of an LAP assisting the palatal augmentation prosthesis (PAP). We delivered both the PAP and LAP to a patient with subtotal glossectomy who experienced saliva drooling and masticatory dysfunction. As the dead space between the reconstructed tongue and dentures decreased in both the vertical and anterior directions, his maximum tongue pressure increased, and the status of salivation and food residue improved. LAP assisted not only for saliva drooling control but also mastication. (Int J Maxillofac Prosthetics 2022;5:13-17) &nbsp

Hoarseness Evaluation and Prosthetic Rehabilitation After Maxillofacial Surgery: A Clinical Report

After maxillofacial surgery, some patients have not only articulation disorder, but also voice disorder. It is important for prosthodontists to know what kind of speech disorder patients have so that they can plan and implement rehabilitation. This report describes the case of a 58-year-old man with a speech disorder that developed after mandibulectomy, maxillectomy, neck dissection, and reconstructive surgery because of tumor. Objective evaluation of voice and articulation clarified that the postoperative speech disorder was due to not hypernasality but hoarseness. Conventional postoperative prosthodontic rehabilitation was performed using a delayed surgical obturator and definitive obturator and his voice was objectively analyzed at each stage. The voice disorder improved over time and the results of the voice evaluation helped the prosthodontist to further plan and implement postoperative prosthodontic rehabilitation. (Int J Maxillofac Prosthetics 2021;4:43-46

Facial Prosthesis Fabricated From Dental Material for an Exposed Reconstruction Plate: A Clinical Report

Facial prostheses are often fabricated for cosmetic and psychological reasons for patients with facial defects after tumor resection. Each case is unique, and fabricating a facial prosthesis that is tailored to the individual patient requires use of specific materials and a degree of flexibility. This article describes a facial prosthesis that was made using an Adams clasp and acrylic resin for an elderly patient with metal exposure after mandibulectomy. (Int J Maxillofac Prosthetics 2022;5:10-12

Prevalence of Possible Dementia in Patients with Maxillofacial Defects and Difficulty of Inserting Obturator in Maxillectomy Patients: Toward Better Provision of Supportive Care

As society ages, it is important to understand the prevalence of dementia and the difficulties of inserting prostheses in patients with maxillofacial defects in order to clarify issues in supportive care. We screened 183 patients for dementia using the revised Hasegawa’s dementia scale (HDS-R) at the Clinic for Maxillofacial prosthetics, Tokyo Medical and Dental University, and investigated age and sex differences in HDS-R score. We asked 47 of the 183 participants about the difficulty of inserting a maxillofacial obturator prosthesis and collected subjective comments, information about the prosthesis, and data from five assessments. Multiple regression analysis was used to reveal factors associated with insertion difficulty. Overall, 8.7% of the participants were judged to have possible dementia. Men were more likely than women to have possible dementia, and the risk increased with age. Of the 47 participants, 26 reported difficulty inserting their prosthesis, 12 of whom attributed it to their oral defect. Fourteen patients advised following doctor’s instructions to practice insertion in order to become accustomed to it. A lower HDS-R score had a significant impact on insertion difficulty. Cognitive function and difficulty inserting maxillary obturator prostheses should be considered in the provision of continuous supportive care to patients with maxillary defects

Evaluation of the color stability of three maxillofacial silicone materials after exposure to beverages: An in vitro study

Purpose: Oral cancer often requires treatments like surgical intervention, involving surgical resection of lips and other facial parts. For those patients, prosthetic rehabilitation following surgery promotes social reintegration. This study explores the color stability of various commercially available silicone materials for facial prostheses when exposed to everyday beverages like coffee and tea. The hypothesis is that these beverages can induce color changes in silicones, simulating conditions of daily use. Material and methods: A total of 90 specimens were fabricated. There were 30 specimens deefor each of 3 nonpigmented silicone elastomers: Silfy, A-2186-F and VST-50 and were immersed in tea or coffee at drinking temperature and evaluated for color changes at time points of 0 h, 1 h, and 6 h. The color was measured with a colorimeter that used the CIE L*a*b* system and the color change ΔΕ was calculated to quantify the color change. Statistical analysis was performed by using the Kruskal-Wallis test, the Mann-Whitney U test, and the Wilcoxon signed-rank Test. The threshold for statistical significance was P < .05. Results: Color change was observed for each of the silicones exposed to the beverages (P < .05). The value of ΔE was significantly higher for A-2186-F compared with VST-50 and Silfy (P < .05 in all beverages at 6 h). The color of the elastomers progressively changed while immersed in the beverages over 6 h. The change in color was significantly greater for coffee compared with tea (P < .05). Conclusions: The color stability of nonpigmented silicone elastomers is inherently low, which contributes to the overall color change of silicone prostheses when they are exposed to beverages that contain pigments. The elastomer A-2186-F had greatest values of ΔE among the materials tested. Color changes of silicone prostheses can be lessened by selecting materials with consideration of color stability to improve their longevity and extend their period of use

Consonant Evaluation During Fabrication of A Removable Prosthesis for A Cleft Lip and Palate Patient: A Clinical Report

Objective consonant evaluation using palatograph tracing and digital acoustic assessment methods are valuable tools for speech assessment that can be used to track speech improvement in patients wearing a removable prosthesis. In this case report, we employed the psychoacoustic parameter – sharpness - to compare the quality of consonants in a cleft palate patient while wearing the old prosthesis, the new prosthesis, and the new prosthesis following palatogram guided modification. The result suggests that sharpness can be successfully analyzed as a criterion to monitor consonants quality during prosthesis fabrication for cleft palate patients. (Int J Maxillofac Prosthetics 2022;5:22-24