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Purpose To introduce an augmented reality (AR) application for students, patients, and practitioners to use to visualize a maxillectomy defect, the associated obturator prosthesis, and the eventual effects on the patient's facial appearance. Materials and methods Various 3D virtual models related to maxillectomy defects and their prosthetic rehabilitations were used to illustrate the handheld AR application. The AR "scene" was created using Vuforia and Unity3D software. Within this scene, 3D virtual models were linked to the target image by detecting a symbol track marker. The final file was saved as an installable application and exported for Android smart devices. Results The target image containing the maxillectomy defect and the prosthetic rehabilitation were successfully visualized interactively in 3D mode using the handheld AR maxillofacial prosthetic application. Conclusion An AR application for visualizing maxillofacial prosthetic data could interestingly be developed as a pedagogic tool to explain prosthetic treatments.

Purpose To assess the feasibility of using an intraoral scanner for data acquisition of maxillectomy defects. Materials and methods In 10 patients who had undergone a maxillectomy, the maxillectomy defects in dentate and edentulous maxillary arches were intraorally scanned. Intraoral photographs were also taken using a digital camera for comparison. Results Adequate scanning was achieved for the nondefect side of the maxilla and for residual teeth. In some cases, it was impossible to scan the maxillectomy defect, especially the deep sites. Conclusion Improved intraoral scanning technology will increase the feasibility of its use in maxillofacial prosthetics.

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.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.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.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.

OBJECTIVES To evaluate the effect of different amounts of triangular mesh reduction on the trueness of digitized complete-arch dentate and edentulous maxillectomy defects models. MATERIAL AND METHODS Twenty gypsum maxillectomy defect models (dentate and edentate group: n=10) were digitized using the Trios 3 intraoral scanner, scanning the teeth, mucosa and maxillectomy defect. These datasets (reference, R0) were saved as standard tessellation language (STL) files, and triangular mesh reduction was performed using Meshmixer's reduction tool. Digital test-datasets with file sizes reduced by 50%(R1), 75%(R2), and 90%(R3) were generated (each: n=20). Each test-dataset was compared to the R0 file using 3D evaluation software (GOM Inspect), applying automated pre-alignment followed by a global best-fit alignment, and root mean square (RMS) 3-dimensional (3D) deviations were calculated. Statistical analyses were performed, at a level of significance of ��=0.05. RESULTS The number of triangles, and STL file size were synchronized with each other and inversely proportional to the amount of mesh reduction. The resulting mean percentages of the STL file sizes were 50.00% for R1, 24.93% for R2, and 10.00% for R3. There were no 3D deviations at 50% triangular mesh reduction. The 3D deviations increased with the amount of mesh reduction: at 75% reduction the median deviations were lower (dentate:0.0016mm, IQR:0.0015-0.0018; edentate:0.0016mm, IQR:0.0015-0.0016), than at 90% (dentate:0.004mm, IQR:0.0038-0.0041; edentate:0.003mm, IQR:0.0036-0.0039). A statistically significant increase in 3D deviations was observed with higher degrees of mesh reduction (p

Patient A 69-year-old Japanese male with squamous cell carcinoma of the right maxilla (T4M0N0) was referred to our department for a preoperative examination. An immediate surgical obturator was fabricated before surgery. He underwent surgical treatment, which included right subtotal maxillectomy and reconstruction with a split skin graft. One week postoperatively, the immediate surgical obturator was modified to expand the nasal cavity for obturator prosthesis. Oral intake was started 12 days postoperatively with an immediate surgical obturator in situ. The definitive obturator was fabricated after the wound surface had healed 8 months postoperatively. Assessment of the nutritional status included body mass index, serum albumin level, resting energy expenditure (REE) measured using indirect calorimetry, and predicted REE using the Harris-Benedict equation. These assessments were performed several times, from the time of admission until the definitive obturator was applied. Discussion Malnutrition occurs frequently in patients with head and neck cancer because this region is vital for swallowing and mastication. Maxillectomy patients require a maxillofacial prosthesis to improve their nutritional status from the preoperative period to recovery. This case report describes maxillofacial prosthetic treatment from the perspective of nutrition. The patient wore the immediate surgical obturator postoperatively, which was followed by marked weight loss after restoration, and then weight gain returned to the normal range when wearing the definitive obturator. Conclusion Maxillofacial prosthetic treatments should make efforts to maintain nutritional status and achieve optimal function and quality of life in patients with head and neck cancers.

Purpose To geometrically evaluate facial asymmetry in patients with mandibulectomy defects with and without their mandibular prostheses in place and to compare the results to a nonpatient group. Materials and methods Facial data from a convenience sample of 16 patients with mandibulectomy defects and a control group of 16 nonpatients were acquired using a noncontact 3D digitizer. Facial asymmetry was evaluated by superimposing a facial scan onto its mirror scan for each patient's 3D dataset using 3D evaluation software. Results Facial asymmetry was significantly different between mandibulectomy patients and control participants. As expected, asymmetry was significantly different in mandibulectomy patients with and without their prostheses. Conclusion Wearing a mandibular prosthesis notably improved facial asymmetry.

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.

Purpose Wearing a sports mouthguard is not only recommended in collision sports, such as American football, boxing, and rugby football, but also in low-contact sports, such as basketball, handball, and soccer. It is recommended to remove oral prosthetic devices while playing sports to avoid the risk of fracturing the device. However, players with maxillectomy must wear obturator-type prosthetic devices for speech, breathing, and deglutition even while playing sports. Therefore, there is a need for an oral appliance to prevent dental injury while playing sports without the risk of fracturing the device for players who have undergone maxillectomy.In this case, we fabricated and proposed overlay-type and obturator-type customized sports mouthguards for a patient who had undergone maxillectomy and assessments of satisfaction, speech intelligibility, nasopharyngeal closure function, and swallowing function while playing soccer. Results The patient was only satisfied with the obturator-type mouthguard, and the results of the speech intelligibility, nasopharyngeal closure function, and swallowing tests using the obturator-type mouthguard showed no differences compared to those associated with the previously used prosthetic device. Conclusions This case may help highlight the importance of providing obturator-type mouthguards for players who have undergone maxillectomy to prevent dental injury and physical and mental discomfort.

The role of the prosthodontist in radiation therapy includes fabrication of radiation therapy prosthetic applicators. Brachytherapy is a form of cancer treatment that involves direct insertion of radioactive implants into the tissue. In the case of vaginal cancer, brachytherapy requires the radiation oncologist to use a device called an applicator. Conventional applicators have limitations in terms of the number of radiation tubes that can be inserted, positioning of the tubes, applicator misfit, and pain when inserted. A well-fitted applicator is needed to improve the orientation of the radiation source toward the target area and to reduce the amount of scatter radiation and tissue irritation. Using an appropriate dental material to make an impression can serve to achieve these aims. This article describes a technique for fabricating an acrylic resin custom-made applicator by using techniques used in dentistry.

PURPOSE To evaluate the feasibility and accuracy of noncontact three-dimensional (3D) digitization systems for capturing facial defects. MATERIALS AND METHODS A stone model of a facial defect was digitized using high-accuracy industrial computed tomography as a reference scan. The model was also scanned using four different types of noncontact 3D digitizers: a laser beam light-sectioning technology with camera system and three different stereophotogrammetry systems. All 3D images were reconstructed with corresponding software and saved as standard triangulated language (STL) files. The 3D datasets were geometrically evaluated and compared to the reference data using 3D evaluation software. Kruskal-Wallis H tests were performed to assess differences in absolute 3D deviations between scans, with statistical significance defined as P < .05. RESULTS The four noncontact 3D digitization systems were feasible for digitizing the facial defect model, although the median 3D deviation of the four digitizers varied. There was a significant difference in accuracy among the digitizers (P < .001). CONCLUSION Digitization of facial defect models using various noncontact 3D digitizers appears to be feasible and is most accurate with laser beam light-sectioning technology. Further investigations assessing digitization of facial defects among patients are required to clinically verify the results of this study.

Purpose The purpose of this survey was to examine the overview of maxillofacial prosthetic treatment at our department, in order to ascertain the actual status of patients and discuss future needs. Methods Subjects were all patients who visited Clinic for Maxillofacial Prosthetics, Dental Hospital, Tokyo Medical and Dental University (TMDU) in the period from January 1, 1980 to December 31, 2014. Using medical records of the Clinic for Maxillofacial Prosthetics, Dental Hospital, TMDU, patients' data including sex, address, referring institution, and primary condition were analyzed throughout the period. Results The number of patients over 35 years was 6219, with a man-to-woman ratio of 6:4. The number of patients in their 60s, 70s, and 80s showed an increasing trend. Patients with tumors accounted for about 50 % of cases in 1980–1984 and increased to 80 % in 2010–2014. Conclusions The survey showed an increasing number of elderly patients and patients with tumors. This suggests that more awareness and education about maxillofacial prosthetics are needed.

PURPOSE This study aimed (1) to geometrically evaluate areas of facial asymmetry in patients with two different types of maxillectomy defect compared to a control group, (2) to geometrically evaluate the effect of an obturator prosthesis on facial asymmetry, and (3) to investigate the correlation between three-dimensional (3D) deviation values and number of missing teeth. MATERIALS AND METHODS Facial data from 13 normal control participants and 26 participants with two types of maxillectomy defect (groups 1 and 2) were acquired with a noncontact 3D digitizer. Facial asymmetry was evaluated by superimposing a facial scan onto its mirror scan using 3D evaluation software. Facial scans with and without obturator prostheses were also superimposed to evaluate the obturator effect. The correlation between 3D deviation values and number of missing teeth was also evaluated. Statistical analyses were performed. RESULTS Facial asymmetry was significantly different between the control group and each maxillectomy defect group (group 1: P < .0001 and P = .020 without and with obturator, respectively; group 2: P < .0001 for both conditions). There were no significant differences in asymmetry between groups 1 and 2 either without or with obturator (P = .457 and P = .980, respectively). There was a significant difference in the obturator effect between groups 1 and 2 (P = .038). 3D deviation values were positively correlated with number of missing teeth in group 1 (r = 0.594, P = .032), but not in group 2. CONCLUSION A noncontact 3D digitizer and 3D deviation assessment were effective for analyzing facial data of maxillectomy patients. Obturators were effective for improving facial deformities in these patients.

Purpose To identify trends in the application of various types of digital technologies in maxillofacial prosthetics by identifying these digital technologies and their characteristics and reviewing the prevalence of applied digital technologies and their recent trends in the maxillofacial prosthetics literature. Materials and methods Five leading peer-reviewed prosthodontics journals were manually searched for maxillofacial prosthetics articles on the use of digital technologies published from January 2008 to December 2017. Descriptive statistics were used to analyze data collected on productivity, type of digital technology used, type of article, type of defect, number of authors, and geographic distribution. Results Of the 336 maxillofacial prosthetics articles screened, 87 (26%) were selected for analysis. A remarkable increase was found in article productivity in the last 5 years (63%) compared to the first 5 years (37%). There was also a notable increase over the last 10 years in all digital technologies used except for evaluation technologies, which remained almost constant. Case reports most frequently mentioned use of digitization technologies (61%), design technologies (66%), and rapid prototyping technologies (66%). Original research articles most frequently mentioned use of evaluation technologies (89%); 39% of these technologies were used for intraoral defects and 27% for extraoral defects. Most often, articles had four to five authors (54%). Most published articles were from the Asia-Pacific region (44%), followed by North America (22%) and Europe (20%). Conclusion Although the application of digital technologies reported in the maxillofacial prosthetics literature has increased notably in leading prosthodontics journals over the last 10 years, total article productivity has remained relatively small.

Maxillectomy for oral tumours often results in debilitating oral hypofunction, which markedly decreases quality of life. Dysphagia, in particular, is one of the most serious problems following maxillectomy. This study used swallowing sounds as a simple evaluation method to evaluate swallowing ability in maxillectomy patients with and without their obturator prosthesis placed. Twenty-seven maxillectomy patients (15 men, 12 women; mean age 66.0 ± 12.1 years) and 30 healthy controls (14 men, 16 women; mean age 44.9 ± 21.3 years) were recruited for this study. Participants were asked to swallow 4 mL of water, and swallowing sounds were recorded using a throat microphone. Duration of the acoustic signal and duration of peak intensity (DPI) were measured. Duration of peak intensity was significantly longer in maxillectomy patients without their obturator than with it (P < .05) and was significantly longer in maxillectomy patients without their obturator than in healthy controls (P < .025 after Bonferroni correction). With the obturator placed, DPI was significantly longer in maxillectomy patients who had undergone soft palate resection than in those who had not (P < .05). These results suggest swallowing ability in maxillectomy patients could be improved by wearing an obturator prosthesis, particularly during the oral stage. However, it is difficult to improve the oral stage of swallowing in patients who have undergone soft palate resection even with obturator placement.

Objective The aims of this study were to reveal the nutritional status of patients after head and neck tumour treatment by using the Mini Nutritional Assessment-Short Form (MNA-SF) and to analyse the factors affecting nutritional status in patients with head and neck tumour. Background Elderly patients with loss of teeth and maxillary/mandibular bone due to head and neck tumour treatment could be at high risk of malnutrition. However, there are few reports on the nutritional status of these patients. Materials and methods Forty-six participants (average age 74.7 years) were selected from patients who visited the maxillofacial prosthetics clinic of Tokyo Medical and Dental University Hospital Faculty of Dentistry in Japan. Nutritional status was evaluated using the MNA-SF. Multiple regression analysis was used to identify predictors affecting MNA-SF score. The candidate explanatory variables were age, sex, maxillofacial prosthesis use, number of residual teeth, resection side, neck dissection and treatment option. Results The results showed that approximately half of the patients were at risk of malnutrition, and a regression equation for MNA-SF score was developed using two predictors: maxillofacial prosthesis use and neck dissection. Conclusion Use of a maxillofacial prosthesis can improve nutritional status. On the other hand, a medical history of neck dissection can decrease nutritional status.

Purpose: The purpose of this study was to geometrically evaluate the effect of prosthetic rehabilitation on the facial appearance of mandibulectomy patients. Materials and Methods: Facial scans (with and without prostheses) were performed for 16 mandibulectomy patients using a noncontact three-dimensional (3D) digitizer, and 3D images were reconstructed with the corresponding software. The 3D datasets were geometrically evaluated and compared using 3D evaluation software. Results: The mean difference in absolute 3D deviations for full face scans was 382.2 μm. Conclusion: This method may be useful in evaluating the effect of conventional prostheses on the facial appearance of individuals with mandibulectomy defects.

This clinical technique provides a key procedure for successful prosthetic treatment in patients with an anatomical compromise after a maxillectomy. When making a preliminary impression, the clinician must keep the handle of the stock tray parallel to the patient's interpupillary line extraorally to maintain the correct position of the tray and to make a record of the inclination of the occlusal plane. This simple consideration during this first step of making a preliminary impression can be an important guide for both dentists and dental technicians. Information about the correct positioning of the tray and the inclination of the occlusal plane obtained by using a stock tray handle will greatly reduce the stress experienced by dentists, dental technicians, and patients during the fabrication of the prosthesis and will ultimately lead to successful prosthetic treatment in patients with anatomic compromise resulting from a maxillectomy.

Objective This study aimed to compare the denture space of edentulous glossectomy patients with that of a control group from the perspective of artificial teeth positioning by using three-dimensional techniques. Background It is known that the shape of the denture space may be affected by tongue resection or reconstruction. However, the details of artificial teeth positioning in these patients remain unclear. Materials and methods Six edentulous glossectomy patients aged 73-83 years and six normal participants aged 74-85 years participated in the study. Piezography was used to elucidate the characteristics of the denture space. For visualisation, piezographic records were scanned using cone beam computed tomography and the data were converted into stereolithographic format. Three-dimensional images of piezographic records were then constructed. Bucco-lingual widths of the mandibular occlusal surface were reproduced, and the camber line of the occlusal surface was set so as to simulate the position of the artificial teeth. The maximum chord of the occlusal surface on the left and right sides was recorded and measured. The discrepancy and ratio of the larger chord to the smaller chord between the right and left sides was calculated and subjected to statistical analyses using the Mann-Whitney U test. Results There were significant differences in discrepancy and ratio between the left and right in the control group and the glossectomy patients (P ˂ .01). The glossectomy patients showed a greater discrepancy and ratio than the control group. Conclusions The simulated artificial teeth positions on the occlusal surface between the right and left side were asymmetric in glossectomy patients.

Purpose The purpose of this study was to investigate the influence of dento-maxillary prosthesis adjustment procedure on levels of salivary cortisol. Methods Nine participants (six men, three women, mean age 65.9 years) took part in this study. Saliva samples were collected before and after dento-maxillary prosthesis adjustment during the four different visits. Free cortisol levels were determined using a salivary cortisol immunoassay kit (expanded-range high-sensitivity salivary cortisol enzyme immunoassay kit, Salimetrics). Besides, original self-report sheets, a 35-item food intake questionnaire, the University of Washington Quality of Life (UW-QOL) questionnaire version 4, and the Geriatric Oral Health Assessment Index (GOHAI) questionnaire were also administered. The changes of salivary cortisol levels were analyzed using 2-level multilevel linear regression, with adjustment for age, sex, and time. Wilcoxon signed-rank test was used to compare scores of the food intake questionnaire, UW-QOL questionnaire, and GOHAI questionnaire. Results Salivary cortisol levels decreased significantly after carrying out the dento-maxillary prosthesis adjustment procedure. During the third adjustment, the salivary cortisol levels were significantly low. In addition, salivary cortisol levels of participants aged 70 years and over were significantly higher than other aged groups. The total scores for grade III–V of the food intake questionnaire increased significantly. Other questionnaires had a trend toward increasing scores, yet the differences were not significant. Conclusions Within the limitations of this study, the results suggest that a reduction in symptoms of discomfort may have an influence on the decrease of salivary cortisol levels in dento-maxillary prosthesis wearers.

Statement of problem A palatogram aids prosthodontists and speech pathologists in evaluating the precise prosthetic treatment needed and the effectiveness of such treatment to improve speech intelligibility. Powder is commonly used to visualize tongue-palate contact, where wetted areas of powder in the oral cavity reveal such contact during palatography. However, discomfort and the risk of aspiration are among the shortcomings of this method, and an improved method is needed. Purpose The purpose of this in vitro study was to examine the feasibility of a new method of palatography that uses airborne-particle–abraded acrylic resin so that wet areas can be easily distinguished from dry areas. Material and methods Seventy-two specimens of heat-polymerized acrylic resin were prepared in 6 different resin colors. After the specimens had been airborne-particle abraded, CIELab color values for each specimen were measured using a colorimeter under dry and wet conditions and recorded. Color difference (ΔE) was then computed, and a paired Student t test, 1-way analysis of variance, and multiple comparison using the Tukey post hoc analysis were applied (α=.05). Results A significant color difference was found between the 2 conditions in all acrylic resin specimens examined. Mean ΔE ranged from 5.58 to 6.76. Conclusions The results indicated that an airborne-particle–abraded acrylic resin surface can show color differences made by wetting on palatograms.

Purpose Accurate evaluation of speech characteristics through formant frequency measurement is important for proper speech rehabilitation in patients after maxillectomy. This study aimed to evaluate the utility of digital acoustic analysis and vowel pentagon space for the prediction of speech ability after maxillectomy, by comparing the acoustic characteristics of vowel articulation in three classes of maxillectomy defects. Materials and methods Aramany's classifications I, II, and IV were used to group 27 male patients after maxillectomy. Digital acoustic analysis of five Japanese vowels-/a/, /e/, /i/, /o/, and /u/-was performed using a speech analysis system. First formant (F1) and second formant (F2) frequencies were calculated using an autocorrelation method. Data were plotted on an F1-F2 plane for each patient, and the F1 and F2 ranges were calculated. The vowel pentagon spaces were also determined. One-way ANOVA was applied to compare all results between the three groups. Results Class II maxillectomy patients had a significantly higher F2 range than did Class I and Class IV patients (p = 0.002). In contrast, there was no significant difference in the F1 range between the three classes. The vowel pentagon spaces were significantly larger in class II maxillectomy patients than in Class I and Class IV patients (p = 0.014). Conclusion The results of this study indicate that the acoustic characteristics of maxillectomy patients are affected by the defect area. This finding may provide information for obturator design based on vowel articulation and defect class.

Purpose: The aim of this study was to evaluate the feasibility and accuracy of using an intraoral scanner to digitize edentulous maxillectomy defects. Materials and Methods: A total of 20 maxillectomy models with two defect types were digitized using cone beam computed tomography. Conventional and digital impressions were made using silicone impression material and a laboratory optical scanner as well as a chairside intraoral scanner. The 3D datasets were analyzed using 3D evaluation software. Results: Two-way analysis of variance revealed no interaction between defect types and impression methods, and the accuracy of the impression methods was significantly different (P = .0374). Conclusion: Digitizing edentulous maxillectomy defect models using a chairside intraoral scanner appears to be feasible and accurate.

Purpose The purpose of this study was to use cortisol awakening response (CAR) to investigate the differences in daily life stress experienced by individuals wearing either a long-term (LT) or a short-term (ST) dento-maxillary prosthesis following head and neck cancer (HNC) resection. Also we used the University of Washington Quality of Life (UW-QOL) version 4 questionnaire to evaluate the differences in quality of life (QOL) scores between ST and LT wearers of a dento-maxillary prosthesis. Methods Salivary samples were collected from 11 LT and 10 ST prosthesis wearers on two consecutive days at two time points, immediately after waking up (T0) and 30min later (T30), by passive drool collection. Cortisol levels were measured using a high sensitivity salivary cortisol enzyme immunoassay kit (Salimetrics, LLC, State College, PA, USA) and CAR (the differences between the cortisol levels at T0 and T30) was compared between LT and ST prosthesis wearers. In addition, both the groups completed the UW-QOL questionnaire and the scores were compared. Results A significant difference was observed in CAR between the two groups. CAR of the ST prosthesis wearers was significantly lower compared with that of the LT prosthesis wearers; moreover, the ST prosthesis wearers revealed significantly lower total UW-QOL scores and there were significant differences in appearance, activity, recreation, speech, and anxiety. Conclusion Within the limitations of this study, the findings suggest that individuals wearing ST dento-maxillary prostheses following HNC resection experience some sort of daily life stress and complicated socio-demographic factors may influence their QOL.

Although digital technology has advanced the visualization of treatment planning and rehabilitation in prosthodontics, the field of maxillofacial prosthetics is in vital need of an accessible document for exchange of interactive three-dimensional (3D) model visualization without requiring installation of any additional software. This article introduces a 3D data documentation method for effective interactive digital visualization in maxillofacial prosthetics using a portable documentation format (PDF).

This case report describes the reproduction of the current obturator of a frail elderly patient using the digitization concept. A computed tomography scanner was used to scan the obturator. The virtual model was created using three-dimensional modeling software. The model was printed using a plastic with a low melting point with a fused deposition modeling technique in a three-dimensional printer and then conventionally processed. The definitive obturator was inserted and evaluated for fit, function, and esthetics and was successfully delivered at the second visit. The patient was satisfied with the oral function and esthetics of the reproduced obturator. This case report confirms the effectiveness of digitization in the reproduction of an obturator that enabled satisfactory oral function and esthetics.

This report describes the postmaxillectomy prosthetic rehabilitation of a child with maxillary chondrosarcoma over an 8-year period. Specifically, it (1) describes the planning and rehabilitation procedures carried out during the period from before the operation to the time when the patient started elementary school and (2) reports the results of evaluations of the patient's oral and psychosocial function conducted during the school phase. The prosthetic treatment plan was separated into two phases (the preschool and school phases) and was started prior to surgery, when an immediate surgical obturator was designed by the surgeons. After the operation, it was considered important to provide the patient and her mother with training regarding how the defect should be cleaned, trismus prevention, and how the prosthesis should be fitted. In addition, esthetic improvements and the ability to speak clearly were also targeted during treatment planning. After surgery, obturators were fabricated in a conventional manner and fitted at the ages of 2, 4, 6, 8, and 10 years. The patient's oral function during the use of the obturators was evaluated objectively. Marked improvements in oral function were seen during both treatment phases. The patient's ability to perform psychosocial functions at school also improved during the use of the obturators.

Objective evaluation of a patient's speech is needed in prosthetic dentistry because the prostheses can affect the intelligibility of speech. Measurement of voice onset time is one evaluation method of consonant production used in phonetic science. The purpose of this study was to confirm the influence of a palatal prosthesis on consonant production by measuring voice onset time.In this study, voice onset time was measured in 10 healthy women (mean age 26.5 years) under two conditions: with and without an experimental palatal prosthesis. In this study, voice onset time of /ta/ and /ka/ were used to determine the effect of wearing a palatal prosthesis; /pa/ was tested as a control, with the null hypothesis that voice onset time of /ta/ and /ka/ would not change when wearing a palatal prosthesis.Medial voice onset time of /pa/, /ta/, and /ka/ syllables without the palatal prosthesis was 22.5 ms, 19.5 ms, and 42.5 ms, whereas that with the palatal prosthesis was 22.5 ms, 23.5 ms, and 55.0 ms. Voice onset times for /ta/ and /ka/ were prolonged when wearing the experimental palatal prosthesis, whereas /pa/ showed no significant difference.Consonant production was affected by wearing a palatal prosthesis, and this change in sound was detected by measuring voice onset time.

Purpose An objective assessment of speech would benefit the prosthetic rehabilitation of maxillectomy patients. This study aimed to establish a simple, objective evaluation of monosyllable /sa/ utterances in maxillectomy patients by using a psychoacoustic system typically used in industry. Materials and methods This study comprised two experiments. Experiment 1 involved analysis of the psychoacoustic parameters (loudness, sharpness and roughness) in monosyllable /sa/ utterances by 18 healthy subjects (9 males, 9 females). The utterances were recorded in a sound-treated room. The coefficient of variation (CV) for each parameter was compared to identify the most suitable parameter for objective evaluation of speech. Experiment 2 involved analysis of /sa/ utterances by 18 maxillectomy patients (9 males, 9 females) with and without prosthesis, and comparisons of the psychoacoustic data between the healthy subjects and maxillectomy patients without prosthesis, between the maxillectomy patients with and without prosthesis, and between the healthy subjects and maxillectomy patients with prosthesis. Results The CV for sharpness was the lowest among the three psychoacoustic parameters in both the healthy males and females. There were significant differences in the sharpness of /sa/ between the healthy subjects and the maxillectomy patients without prosthesis (but not with prosthesis), and between the maxillectomy patients with and without prosthesis. Conclusion We found that the psychoacoustic parameters typically adopted in industrial research could also be applied to evaluate the psychoacoustics of the monosyllable /sa/ utterance, and distinguished the monosyllable /sa/ in maxillectomy patients with an obturator from that without an obturator using the system.

Purpose: The purpose of this study was to establish an evaluation method using a Nasometer, with several monosyllabic test words, to reveal the level of air leakage in maxillectomy patients without limitations due to language or ability to read.Methods: 20 normal Japanese (Group 1) and 20 international adults (Group 2), were asked to read 7 monosyllables, (5 vowels and 2 combined vowels, /a/, /i/, /u/, /e/, /o/, /am/, /aj/), 6 times each and 12 Japanese maxillectomy patients (Group 3) were asked to read only 3 monosyllables (/a/, /am/, /aj/) 6 times each. The “Nasalance Score” was calculated using a Nasometer (Nasometer II, model 6400 KayPentax, Lincoln Park, NJ, USA).Results: Coefficient of variations (CVs) of three monosyllables /a/, /am/, /aj/ of Group 1 and Group 2 showed less than 0.33. There is significant difference in all pairs of three monosyllables between Group 1 and Group 3 (p < 0.05).Conclusion: Using a Nasometer, these three monosyllables, /a/, /am/ and /aj/, could be used as standard test words and could reveal the level of air leakage in maxillectomy patients.

The current systematic review was performed to assess the functional outcomes of implant-prosthetic treatment on patients who have had surgical resection of oral cavity tumors. The assessment of function, satisfaction, or quality of life (QoL) were the major outcomes that evaluated preoperative and/or before and after implant-prosthetic treatment. Only eight published studies fulfilled the inclusion criteria. Three publications evaluated chewing ability, masticatory performance, and neuromuscular function, and the other five publications used questionnaire as a method of assessment. These publications mainly reported on implant-prosthetic treatment in mandibulectomy patients. It was found that implant-retained prosthesis had a beneficial effect on masticatory performance and masseter muscle activity on the defect side, but not on the non-defect side. Swallowing threshold performance and jaw movement parameters showed no significant differences between non-implant-retained prosthesis and implant-retained prosthesis. Significant improvement in prosthesis and patients' satisfaction with implant-retained prosthesis compared to non-implant-retained prosthesis was observed. However, general improvement in patients' QoL was not observed after implant-prosthetic treatment. Patients with intraoral resection might benefit from implant-retained prosthesis with regard to masticatory function and satisfaction. However, future clinical trials with an adequate sample size are needed to identify the group of patients who are likely to benefit from the implant-prosthetic treatment modality.

Acoustic evaluation is valuable for guiding the treatment of maxillofacial defects and determining the effectiveness of rehabilitation with an obturator prosthesis. Model simulations are important in terms of pre-surgical planning and pre- and post-operative speech function. This study aimed to evaluate the acoustic characteristics of voice generated by an articulation simulation system using a vocal tract model with or without artificial maxillectomy defects. More specifically, we aimed to establish a speech simulation system for maxillectomy defect models that both surgeons and maxillofacial prosthodontists can use in guiding treatment planning. Artificially simulated maxillectomy defects were prepared according to Aramany's classification (Classes I-VI) in a three-dimensional vocal tract plaster model of a subject uttering the vowel /a/. Formant and nasalance acoustic data were analysed using Computerized Speech Lab and the Nasometer, respectively. Formants and nasalance of simulated /a/ sounds were successfully detected and analysed. Values of Formants 1 and 2 for the non-defect model were 675.43 and 976.64 Hz, respectively. Median values of Formants 1 and 2 for the defect models were 634.36 and 1026.84 Hz, respectively. Nasalance was 11% in the non-defect model, whereas median nasalance was 28% in the defect models. The results suggest that an articulation simulation system can be used to help surgeons and maxillofacial prosthodontists to plan post-surgical defects that will be facilitate maxillofacial rehabilitation.

A 47-year-old man underwent surgical resection and reconstruction with a fibula osteocutaneous flap. After the surgery, a surgical obturator was placed and adjusted. After flap healing, a conventional obturator was fabricated with polymethyl methacrylate resin and retained by the anatomical undercuts around the reconstructed fibula bone flap and the posterior part of the defect. As the defect shape changed with time, a second conventional obturator was fabricated and fitted. No further recurrence of myoepithelioma was observed for 2 years, and the patient was satisfied with the obturator during mastication and speech; however, despite having no major complaints, the patient found it difficult to chew on the right side, and the obturator was displaced slightly downward when the mouth was opened wide and shifted when chewing hard and sticky food. Thus, an implant-retained obturator was suggested to provide better retention and stability. Four dental implants were therefore placed into the fibula bone, although one did not osseointegrate because either primary stability was insufficient or overload was affected in the nonloaded implant environment and was replaced. After fitting custom abutments with a magnet, an implant-retained obturator was placed, and the patient was satisfied with the outcome. During 3 years of follow-up, no issues were noted with the implant bodies, abutments, obturator, or reconstructed site. The conventional obturator was displaced slightly downward when the patient opened his mouth wide, and it shifted when chewing hard and sticky food because there was limited fibula bone at the reconstruction site and more available posteriorly. For better retention and stability, the implant-retained obturator was fabricated with a custom abutment and magnetic retention. The patient was satisfied with the results, as improved implant retention increased the stability of the prosthesis. This clinical report describes the rehabilitation of a bilateral maxillectomy patient with a free fibula osteocutaneous flap and an implant-retained obturator. The patient's oral functions were improved when the prosthesis was stabilized by means of dental implants and custom abutments.

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=0.026andZ=−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.

Statement of problem Wind instrument players may dread dental treatment because changes in the oral cavity can affect their performance. However, few studies have investigated the influence of such changes, particularly prosthesis-induced morphologic changes, on the performance of wind instrument players. Purpose The purpose of this study was to determine the effects of prosthesis-induced morphologic changes in the oral cavity on the performance of wind instrument players. Material and Methods Seven women were asked to play a recorder with and without an experimental palatal appliance. Their performances were analyzed by psychoacoustic analysis, with loudness as a parameter, and by performable range analyses with Voice Range Profile software. The Wilcoxon signed rank test was used for the statistical analyses. Results Differences between moderately loud and very soft sounds ( P =.043) and between very loud and very soft sounds ( P =.027), as well as the performable range of frequency and intensity ( P =.028), all decreased significantly in the presence of the palatal prosthesis. Conclusions The results of this study suggest that changes in the oral cavity caused by the presence of a prosthesis affect the psychoacoustic features and the performable range of frequency and intensity during the playing of wind instruments.

Some dental patients use the orofacial region to play wind instruments; however, musical performance has not been objectively evaluated following prosthodontic treatment in such patients. The purpose of this report was to describe prosthodontic treatment for a clarinet player using sound analysis. The patient required a removable partial denture for his maxillary anterior teeth. Sound analysis was performed before and after denture adjustment, and the patient completed a questionnaire regarding his perceptions while playing his clarinet. After adjustment, the denture showed better performance, and patient satisfaction increased compared with that before adjustment.

The objective of this study is to evaluate the usefulness of a denture adhesive in edentulous patients after maxillectomy.Maxillectomy patients suffer from functional impairments. Denture adhesives (DAs) are the solution in such patients. However, little is known about DAs in maxillectomy patients.Eight edentulous patients who had undergone maxillectomy were included and divided into three groups. Group 1 (half ≤ remaining residual maxilla), Group 2 (quarterremaining residual maxillahalf) and Group 3 (remaining residual maxilla ≤ quarter). They were evaluated by a speech intelligibility test and a mixing ability test, respectively. A cream-type DA called New Poligrip(®) (GlaxoSmithKline, Tokyo, Japan) was used.Applying the DA, speech intelligibility showed a higher score than the data without DA.The effects of using a DA depend on the amount of the remaining residual maxilla. Our study showed that if the remaining residual maxilla is less than a quarter (Group 3), it is difficult to have confidence in the effectiveness of the DA to improve masticatory function. On the other hand, the use a DA showed improved speech intelligibility test values in all groups.

Purpose Subjective speech evaluation is important in maxillofacial rehabilitation. In previous research, the automatic speech intelligibility test system using monosyllables was developed using a computerized speech recognition technique, and it was suggested that the system may effectively be used in evaluated maxillectomy patients' speech. However the system showed some disadvantages such as the low sensitiveness for the mild speech disorders. In this study, the system was remodeled employing sentences as test stimuli to overcome the shortcomings. The new system was used to evaluate speech of normal adults and maxillectomy patients. Methods The speech of 10 normal adults and 13 maxillectomy patients was evaluated using the automatic conversation intelligibility test system that employed sentences as test stimuli. Normal subjects repeated the test for three times on different days. The patients' utterances were examined in two conditions: with and without prostheses. The results from patients with and without prostheses were compared to each other, and also compared with their corresponding conversation intelligibility obtained using a perceptual method. Results In normal subjects, there was no significant difference in their scores using the automatic conversation intelligibility test on three different days. The result of the automatic test was significantly improved in patients by wearing prostheses. There were significant correlations between the result of the automatic test and the corresponding conversation intelligibility both in patients with prostheses and without prostheses. Conclusion It was indicated that the automatic conversation intelligibility test system using sentences as stimuli would be effectively used in evaluating maxillectomy patients' speech.

Purpose: The aim of this study was to investigate the factors influencing the outcome of prostheses on speech rehabilitation of mandibulectomy patients.Methods: Eleven patients (6 males and 5 females) who underwent mandibulectomy without glossectomy because of a tumor participated in the study. A Speech Intelligibility (SI) test was applied without and with a prosthesis to evaluate their speech ability. The type of resection, whether soft tissue grafting was undertaken or not, the continuity of mandibular bone, and the number of remaining teeth related to the stability of the prosthesis were determined from the medical records. The some of acoustic features, Formant 1 and Formant 2 range, were investigated to evaluate objectively the limitation of tongue movement. Five questionnaires were sent out to evaluate subjectively the difference in sense of discomfort while speaking with and without the prosthesis. These eleven items were entered into stepwise multiple regression models to determine the predictors of the differences in SI score without and with a prosthesis.Results: Three variables, the ease of tongue movements, whether soft tissue grafting was undertaken or not, and whether the mandibular bone was continuous or not, contributed to the recovery of speech ability with prosthodontic treatment.Conclusion: The ease of tongue movement, no soft tissue grafting, and the continuity of mandibular bone contribute to the recovery of speech ability with prosthodontic treatment.

Purpose Several previous reports have described factors that affect masticatory function. However, there are no known predictors that affect the food mixing ability of the masticatory function, and it has been impossible to predict masticatory function in mandibulectomy and/or glossectomy patients. The purpose of the present study was to develop a numerical formula that could predict the food mixing ability of the masticatory function among mandibulectomy and/or glossectomy patients. The null hypothesis of the study was that five predictors, namely mandibulectomy, mandibular continuity, number of residual mandibular teeth, occlusal units and tongue movement score, were unable to account for the mixing ability index (MAI) in mandibulectomy and/or glossectomy patients. Methods The subjects were 20 patients who had undergone mandibulectomy and/or glossectomy. The above-described five predictors were assessed. Tongue movement was evaluated with a tongue movement test and the MAI was evaluated with a mixing ability test. Multiple regression analysis was used to examine whether the five predictors affected the MAI after prosthetic treatment. Results A regression equation was determined for the five predictors ( R 2 =0.83; adjusted R 2 =0.77; p Conclusion The obtained regression equation could successfully account for the MAI in mandibulectomy and/or glossectomy patients.

Postoperative head and neck cancer patients suffer from speech disorders, which are the result of changes in their vocal tracts. Making a solid vocal tract model and measuring its transmission characteristics will provide one of the most useful tools to resolve the problem. In binary conversion of X-ray computed tomographic (CT) images for vocal tract reconstruction, nonobjective methods have been used by many researchers. We hypothesized that a standardized vocal tract model could be reconstructed by adopting the Hounsfield number of fat tissue as a criterion for thresholding of binary conversion, because its Hounsfield number is the nearest to air in the human body. The purpose of this study was to establish a new standardized method for binary conversion in reconstructing three-dimensional (3-D) vocal tract models. CT images for postoperative diagnosis were secondarily obtained from a CT scanner. Each patient's minimum settings of Hounsfield number for the buccal fat-pad regions were measured. Thresholds were set every 50 Hounsfield units (HU) from the bottom line of the buccal fat-pad region to -1024 HU, the images were converted into binary values, and were evaluated according to the three-grade system based on anatomically defined criteria. The optimal threshold between tissue and air was determined by nonlinear multiple regression analyses. Each patient's minimum settings of the buccal fat-pad regions were obtained. The optimal threshold was determined to be -165 HU from each patient's minimum settings of the Hounsfield number for the buccal fat-pad regions. To conclude, a method of 3-D standardized vocal tract modeling was established.