Search

Objectives: Evaluating the effect of shape and size of implant scan body on the accuracy of optical 3D scanning., Materials and Methods: Fifteen PEEK scan bodies were milled, including 1 spherical, 9 cylindrical, and 5 cuboidal. The 3D position and angulation of each scan body were measured using a CMM 3 times and a laboratory scanner 10 times. The linear and angular trueness and precision of the scans were calculated by comparing with the CMM measurements., Results: The linear accuracy of the cylindrical scan bodies (9.5 ± 6.2 µm) was significantly higher than those of the cuboidal (17.7 ± 8.1 µm) and spherical scan bodies (12.5 ± 6.5 µm). The cuboidal (0.050±0.009°) showed significantly better angular accuracy than the cylindrical (0.065±0.040°). In the cylindrical group, the narrow (∅4.8 mm) demonstrated significantly inferior accuracy than the wider (∅5.5 mm and ∅6.5 mm)(p = 0.003). The tall (12 mm) showed significantly higher angular trueness than the shorter (8 and 4 mm)(p < 0.001). In the cuboidal group, the 24 mm 2 exhibited significantly poorer angular trueness compared to the 18 mm 2 and 30 mm 2 (p < 0.001) CONCLUSIONS: The shape and size of the implant scan body significantly affect the scanning accuracy. Spherical scan bodies cannot transfer implant angulation. Scan bodies with a size of >∅4.8 mm and >8 mm seem accurate for transferring the 3D implant position., Clinical Significance: The shape and size of scan bodies directly influence the accuracy of 3D scanning. Well-designed scan bodies offer better transfer results, which is crucial for ensuring passive fit of implant prostheses and improving long-term clinical outcomes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: To develop a new post-processing strategy that utilizes an auxiliary device to adjust intraoral scans and improve the accuracy of 3D models of complete-arch dental implants., Materials and Methods: An edentulous resin model with 6 dental implants was prepared. An auxiliary device, consisting of an opaque base and artificial landmarks, was fabricated and mounted onto the resin model. Twenty intraoral scans (raw scans) were taken using this setup. A new post-processing strategy was proposed to adjust the raw scans using reverse engineering software (verified group). Additionally, ten conventional gypsum casts were duplicated and digitized using a laboratory scanner. The linear and angular trueness and precision of the models were evaluated and compared. The effect of the proposed strategy on the accuracy of complete-arch intraoral scans was analyzed using one-way ANOVA., Results: The linear trueness (29.7 µm) and precision (24.8 µm) of the verified group were significantly better than the raw scans (46.6 µm, 44.7 µm) and conventional casts (51.3 µm, 36.5 µm), particularly in cross-arch sites. However, the angular trueness (0.114°) and precision (0.085°) of the conventional casts were significantly better than both the verified models (0.298°, 0.168°) and the raw scans (0.288°, 0.202°)., Conclusions: The novel post-processing strategy is effective in enhancing the linear accuracy of complete-arch implant IO scans, especially in cross-arch sites. However, further improvement is needed to eliminate the angular deviations., Clinical Significance: Errors generated from intraoral scanning in complete edentulous arches exceed the clinical threshold. The elimination of stitching errors in the raw scans particularly in the cross-arch sites, through the proposed post-processing strategy would enhance the accuracy of complete-arch implant prostheses., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Objectives: This study aimed to investigate the colour accuracy of digital photographs captured by a single-lens reflex (SLR) camera and a smartphone camera in a clinical setting., Methods: Dentate subjects were recruited, and their maxillary anterior teeth were photographed along with a colour target and a dental shade guide. There were eight groups: Group 1: SLR camera with a 100 mm macro-lens and a ring-flash (SLRC); Group 2: SLRC with a polarizer; Group 3: SLRC with white-balance calibration; Group 4: SLRC with a polarizer and white-balance calibration. Groups 5 to 8 were similar to Groups 1 to 4, except a smartphone camera and an external light source (SC) were used. The CIE LAB coordinates of the colour target, shade guide, and centre of the maxillary right central incisor (tooth 11) in the digital photographs were retrieved. The colour difference ΔE=[(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 ] 1/2 to the reference colour coordinates or the reading of the dental spectrophotometer was calculated. The results were analysed by the Kruskal-Wallis test at α=0.05 with Bonferroni correction., Results: Thirty-nine subjects were photographed. SLRC with a polarizer showed the largest ΔE in this study (P<0.001). When capturing tooth 11, SLRC with calibrated white-balance resulted in the smallest ΔE in this study (P<0.001), and the use of a polarizer and/or calibrated white-balance did not result in a smaller ΔE than that of SC alone (P>0.001)., Conclusion: Calibration for white-balance is recommended for the SLRC. The use of a polarizer does not show an improvement in colour accuracy. SC alone may be sufficient for intraoral photography., Clinical Significance: When capturing intraoral photography using a single-lens reflex camera, it is recommended to calibrate the white-balance. The use of a polarizer does not significantly improve colour accuracy. However, a smartphone camera with an external light source can serve as a viable alternative., Competing Interests: Declaration of Competing Interest The study has been presented at the 2022 IADR/APR General Session & Exhibition., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Objectives: The aim of this in-vitro study was to compare the virtual techniques for registering single-implant position to the physical gold standard using a universal-coordinate system., Materials and Methods: Thirty dentate maxillary resin models with a dental implant inserted in the incisor region were prepared. On each model, a tooth-supported acrylic stent with a 1 cm x 1 cm x 1 cm cubic-corner (CC) was prepared. The Cartesian x,y,z-coordinate of the implant neck and apex were measured physically by a coordinate-measuring machine (CMM) with reference to this CC and served as the gold-standard. The resin models were scanned by a benchtop scanner (Group BS), cone-beam computed tomography (Group CBCT), and intraoral scanner (Group IOS). Stone casts, poured from open-tray polyether impression of the resin models, were scanned by the benchtop scanner (Group BS-cast). The implant neck and apex coordinates with reference to the CC were measured and the differences in the coordinates (∆x, ∆y, ∆z) and distance r from the gold standard were calculated. The data were analyzed by one-sample t-test and one-way ANOVA/Kruskal-Wallis test with the level of significance set at 0.05., Results: The implant neck and apex positions of Group BS were statistically different from that of the CMM, r>0 (p<0.001). Group IOS showed a significant less ∆z and r at the implant neck than Group BS-cast (p = 0.006). No significant difference was found in the coordinates and distance at implant apex among Groups BS, CBCT, IOS and BS-cast., Conclusions: The physical measurements could be adopted as the gold standard in assessing the single-implant positions. The IOS was more accurate in registering the single-implant neck positions than scanning of the cast., Clinical Significance: A universal-coordinate system defined by the cubic-corner allows comparing the virtual techniques in registering single-implant positions to the physical gold standard., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objectives: To develop a novel auxiliary device for improving the accuracy of intraoral implant scanning in the complete-edentulous arch., Materials and Methods: A standard model of edentulous maxilla with six dummy implants was prepared. Scan bodies were attached to the model, which was scanned by a laboratory scanner. A simulated mucosa (Group 0), a resin base (Group 1), a resin base with a cuboidal reference block and 4 fiduciary spheres (Group 2) or artificial teeth (Group 3) in between the implants were mounted on the model, respectively. Each group were consecutively scanned using an intraoral scanner (n = 10). The scans were analysed for trueness and precision in inter-implant distances and angles by inspection software. Effects of the auxiliary device and different quadrants on the accuracy of complete-arch intraoral scanning were analysed by two-way ANOVA., Results: Significant effects of the auxiliary device and quadrant were found on both linear and angular accuracies. The lowest linear accuracy was found in group 0. Group 1 and group 3 showed the best linear accuracy in quadrant 1 and quadrant 2, respectively. Group 2 showed the least angular precision among the three groups., Conclusions: The three designs of auxiliary devices significantly improved the accuracy of complete-arch intraoral implant scanning. The base-only design showed good scanning accuracy in a single quadrant, while the base with tooth-shaped landmarks design showed better accuracy in cross-arch. The fiduciary spheres might compromise the precision of scanning., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: To compare the accuracies of 4 laboratory scanners using a new custom-made block for complete-arch implant rehabilitation., Materials and Methods: A block comprised 4 cylinders, with 2 in the anterior (0° angulation) and 2 in the posterior region (45° distal angulation) (Experimental group) and a standard block with 2 parallel cones in 16° taper (ISO group), were fabricated. Both blocks were scanned consecutively for 15 times by 4 laboratory scanners: IScan, Zfx, 3Shape, and KaVo. Measurements were also made by a coordinate measuring machine (CMM) as the reference. Acquired digital models were inspected with a metrology software. Linear and angular distortions were computed evaluation of trueness, precision and expanded uncertainty of scanners. Effects of blocks and scanners on the scanning trueness and precision were analyzed by Two-way ANOVA (α = 0.05)., Results: The linear trueness and precision of scanners was significantly poorer when the Experimental block instead of ISO block was used. Significant greater distortions were noticed at the 45° sites than the 0° sites and no significant effect of inter-implant distance on the scanning accuracy was found. Zfx, IScan and 3Shape exhibited comparable expanded uncertainties (10.6∼11.8) but KaVo showed the greatest (19.3) in complete-arch implant scans., Conclusion: The ISO block might not be more suitable than the Experimental block for evaluating the accuracy of laboratory scanner for complete-arch implant scanning. All the scanners tested except one demonstrated acceptable accuracy for complete-arch implant digitization. Scanning accuracy was compromised by unfavourable angulation of implants., Clinical Significance: It is questionable whether the laboratory scanners validated for tooth-borne cases could also perform well for implant cases. It might be necessary to develop a new calibration object specifically for complete-arch implant scenarios to verify the capability of laboratory scanners in the implant workflow., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Purpose: To systematically review the current evidence on clinical and patient-reported outcomes of implant-supported palatal obturator prostheses., Materials and Methods: An electronic search of the PubMed, Web of Science, and Cochrane databases was carried out in June 2019. The titles and abstracts of all articles were screened by two independent reviewers. The references of the subsequently selected studies were further screened for potential articles. Assessment of the selected full texts was performed independently according to established inclusion and exclusion criteria. The quality of the selected studies was determined using the Newcastle-Ottawa scale. Interrater agreement on study selection was calculated using Cohen kappa statistic., Results: The search yielded a total of 2,797 records. Ten studies were selected for data extraction, with a Cohen kappa value of 0.856. Five studies were prospective, and five were retrospective. The survival rates for conventional implants ranged from 21.42% to 100%, whereas for zygomatic implants, the survival rates varied from 30% to 100%. Four studies reported prosthodontic complications, with screw loosening being the most common. Patient quality of life (QoL) was analyzed in six studies., Conclusion: In spite of the limitations of the present review, it can be concluded that the clinical outcomes are acceptable in terms of survival rates, implant and prosthodontic complications, and QoL associated with implant-supported maxillary obturator prostheses. QoL of implant-supported prostheses in these patients are acceptable. The general study design was not homogenous between studies.

Converting the patient's clinical information into the virtual world is a prerequisite for the computer-aided design and computer-aided manufacturing (CAD-CAM) of dental restorations. This article describes a modified facebow which facilitates the radiation-free registration of the maxillary teeth to a 3-dimensional face image for transfer to a virtual articulator. This facebow can be easily fabricated with minimal materials and adjusted to fit different patients; its error in tooth registration was demonstrated to be less than 1 mm., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objectives: To investigate the salivary anionic changes of patients with nasopharyngeal carcinoma (NPC) treated by radiotherapy., Material and Methods: Thirty-eight patients with T1-4, N0-2, M0 NPC received conventional radiotherapy. Stimulated whole saliva was collected at baseline and 2, 6 and 12 months after radiotherapy. Salivary anions levels were measured using ion chromatography., Results: A reduction in stimulated saliva flow and salivary pH was accompanied by sustained changes in anionic composition. At 2 months following radiotherapy, there was a significant increase in chloride, sulphate, lactate and formate levels while significant reductions in nitrate and thiocyanate levels were found. No further changes in these anion levels were observed at 6 and 12 months. No significant changes were found in phosphate, acetate, or propionate levels throughout the study period., Conclusions: Conventional radiotherapy has a significant and prolonged impact on certain anionic species, likely contributing to increased cariogenic properties and reduced antimicrobial capacities of saliva in NPC patients post-radiotherapy.

Statement of Problem: Fluorophlogopite glass ceramic (FGC) is a biocompatible, etchable, and millable ceramic with fluoride releasing property. However, its mechanical properties and reliability compared with other machinable ceramics remain undetermined., Purpose: The purpose of this in vitro study was to compare the mechanical properties of 3 commercially available millable ceramic materials, IPS e.max CAD, Vitablocs Mark II, and Vita Enamic, with an experimental FGC., Material and Methods: Each type of ceramic block was sectioned into beams (n=15) of standard dimensions of 2×2×15 mm. Before mechanical testing, specimens of the IPS e.max CAD group were further fired for final crystallization. Flexural strength was determined by the 3-point bend test with a universal loading machine at a cross head speed of 1 mm/min. Hardness was determined with a hardness tester with 5 Vickers hardness indentations (n=5) using a 1.96 N load and a dwell time of 15 seconds. Selected surfaces were examined by scanning electron microscopy and energy-dispersive x-ray spectroscopy. Data were analyzed by the 1-way ANOVA test and Weibull analysis (α=.05). Weibull parameters, including the Weibull modulus (m) as well as the characteristic strength at 63.2% (η) and 10.0% (B10), were obtained., Results: A significant difference in flexural strength (P<.001) was found among groups, with IPS e.max CAD (341.88 ±40.25 MPa)>Vita Enamic (145.95 ±12.65 MPa)>Vitablocs Mark II (106.67 ±18.50 MPa), and FGC (117.61 ±7.62 MPa). The Weibull modulus ranged from 6.93 to 18.34, with FGC showing the highest Weibull modulus among the 4 materials. The Weibull plot revealed that IPS e.max CAD>Vita Enamic>FGC>Vitablocs Mark II for the characteristic strength at both 63.2% (η) and 10.0% (B10). Significant difference in Vickers hardness among groups (P<.001) was found with IPS e.max CAD (731.63 ±30.64 H(V))>Vitablocs Mark II (594.74 ±25.22 H(V))>Vita Enamic (372.29 ±51.23 H(V))>FGC (153.74 ±23.62 H(V))., Conclusions: The flexural strength and Vickers hardness of IPS e.max CAD were significantly higher than those of the 3 materials tested. The FGC's flexural strength was comparable with Vitablocs Mark II. The FGC's Weibull modulus was the highest, while its Vickers hardness was the lowest among the materials tested., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objectives: To determine the prevalence of proximal contact loss between posterior implant-supported prostheses and the adjacent anterior natural tooth and to identify potential contributing factors., Materials and Methods: Forty-five consecutive patients, who had received either implant-supported fixed partial denture (FPD) or implant-supported single crown (SC) in the posterior region and were under regular review, were recruited. Interproximal space was assessed by the number of matrix bands that could be placed, and tooth mobility was assessed by Periotest®. A self-reported questionnaire was administered. Effects of various patient and prosthesis parameters on interproximal space were analyzed by Kruskal-Wallis test or Mann-Whitney U test. Correlations were tested by Spearman's rank correlation coefficient. Differences were considered significant if P < 0.05., Results: Forty-three of 66 (65%) prostheses showed proximal contact loss. Frequent food packing was reported in 40% of the prostheses. The mean interproximal space was 167 (SD = 125) μm, and it was positively correlated with patients' age (P = 0.031) and time since prostheses delivery (P = 0.002). The interproximal space in the FPD group was significantly larger than the SC group (P = 0.008)., Conclusion: Proximal contact loss is not uncommon in posterior implant-supported prostheses. In this study, age of the patient, prosthesis type and time since delivery of prosthesis were found to be contributing factors., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The majority of studies examining anionic composition in human saliva have focused on inorganic anions only, and accompanying organic anion concentration has often been overlooked in the development of artificial salivas. The purpose of this study was to examine the major organic anionic species profile of human saliva, with a view to gaining further insight into human salivary chemistry., Methods: Unstimulated whole saliva was collected from 11 healthy volunteers over a period of 18months. Samples were subjected to ion chromatography for detection and quantification of organic and inorganic anions., Results: Among organic anions, acetate was predominant (0.24±0.38mmol/l), with lactate (0.01±0.04mmol/l), propionate (0.03±0.07mmol/l), and formate (0.02±0.03mmol/l) detected at lower levels. Acetate, propionate, and formate were detected in at least 80% of the saliva samples. Positive partial correlations were found between phosphate and sulfate (r=0.510, p-value=1.545×10(-4)), and between propionate and acetate (r=0.836, p-value=7.510×10(-14))., Conclusion: Organic anionic species were consistently detected at low levels in saliva samples collected longitudinally over a period of 18months. These salivary components must be considered in order to understand saliva chemistry, and should not be neglected during the continuing development of artificial salivas., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Radiotherapy may compromise the integration of implant and cause implant loss. Implant surface modifications have the possibility of promoting cell attachment, cell growth, and bone formation which ultimately enhance the osseointegration process. The present study aimed to investigate the effects of calcium phosphate nanocrystals on implant osseointegration in irradiated bone. Sixteen rabbits were randomly assigned into control and nano-CaP groups, receiving implants with dual acid-etched surface or dual acid-etched surface discretely deposited of nanoscale calcium-phosphate crystals, respectively. The left leg of all the rabbits received 15 Gy radiation, followed by implants placement one week after. Four animals in each group were sacrificed after 4 and 12 weeks, respectively. Implant stability quotient (ISQ), ratio of bone volume to total volume (BV/TV), bone growth rate, and bone-to-implant contact (BIC) were evaluated. The nano-CaP group showed significantly higher ISQ (week 12, P = 0.031) and bone growth rate (week 6, P = 0.021; week 9, P = 0.001) than that in control group. No significant differences in BV/TV and BIC were found between two groups. Titanium implant surface modified with CaP nanocrystals provides a potential alternative to improve bone healing around implant in irradiated bone.

Objective: The present study aimed to investigate the effect of fluoride-modified titanium surface on adhesion of irradiated osteoblasts., Materials and Methods: Fluoride-modified surface was obtained and the morphology, roughness, and chemical composition of the surface were evaluated by scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy, respectively. The adhesion of irradiated osteoblast-like cells, in terms of number, area, and fluorescence intensity on the titanium surface, was evaluated using immunofluorescence staining., Results: Numerous nanosize pits were seen only in the F-TiO surface. The pits were more remarkable and uniform on F-TiO surface than on TiO surface; however, the amplitude of peaks and bottoms on F-TiO surface appeared to be smaller than on TiO surface. The Sa value and Sdr percentage of TiO surfaces were significantly higher than those of F-TiO surface. The concentrations of main elements such as titanium, oxygen, and carbon were similar on both surfaces. The number of irradiated osteoblasts adhered on the control surface was larger than on fluoride-modified surface. Meanwhile, the cells on the fluoride-modified surface formed more actin filaments., Conclusions: The fluoride-modified titanium surface alters the adhesion of irradiated osteoblasts. Further studies are needed to investigate the proliferation, differentiation, maturation, gene expression, and cytokine production of irradiated osteoblasts on fluoride-modified titanium surface.

Excessive movable tissue is a challenge in complete denture prosthetics. A modified impression technique is presented with polyvinyl siloxane impression material and a custom tray with relief areas and perforations in the area of the excessive movable tissue., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Molar-incisor hypomineralization (MIH) is a developmental enamel hypomineralized condition characteristically involving the first permanent molars and sometimes also the incisors. The affected teeth are predisposed to tooth surface loss (TSL) which may not only compromise the esthetics and function but also endanger the pulp and longevity of the teeth. This report describes the management of a patient with MIH complicated with localized TSL and lack of occlusal clearance due to dentoalveolar compensation. The atypical TSL pattern involved all anterior teeth and required the placement of Dahl appliances on both arches.

Aim: The aim of the present study was to compare the effectiveness of DNA extraction using an extraction kit against the standard boiling technique for the detection of Epstein-Barr virus (EBV) DNA in nasopharyngeal carcinoma (NPC) patients., Methods: Stimulated whole saliva samples from newly-diagnosed NPC patients were collected. EBV DNA was extracted by both techniques (n = 23) followed by quantitative real-time polymerase chain reaction (PCR) using the primer/probe set for BALF5., Results: The results of the quantitative real-time PCR were reproducible in both groups. The two techniques were moderately correlated (r = 0.67, P < 0.05), and the degree of agreement was good. However, the mean EBV DNA level in the boiling group (3.02 ± 8.67 × 10(6) copies/μL) was significantly higher than the extraction kit group (1.15 ± 2.66 × 10(6) copies/μL) (P < 0.05). The EBV DNA level was higher in patients at an advanced overall stage (P = 0.05)., Conclusion: The results of the present study showed that the performance of the extraction kit was not superior to the simple boiling technique for the detection of salivary EBV DNA in NPC patients using real-time PCR. The salivary EBV DNA level in patients at an advanced overall stage appeared to be higher than in patients at an early stage., (© 2013 Wiley Publishing Asia Pty Ltd.)

Objectives: To investigate the impact of cover screw, resin embedment, and implant angulation on artifact of microcomputed tomography (micro-CT) scanning for implant., Materials and Methods: A total of twelve implants were randomly divided into 4 groups: (i) implant only; (ii) implant with cover screw; (iii) implant with resin embedment; and (iv) implants with cover screw and resin embedment. Implants angulation at 0°, 45°, and 90° were scanned by micro-CT. Images were assessed, and the ratio of artifact volume to total volume (AV/TV) was calculated. A multiple regression analysis in stepwise model was used to determine the significance of different factors. One-way ANOVA was performed to identify which combination of factors could minimize the artifact., Results: In the regression analysis, implant angulation was identified as the best predictor for artifact among the factors (P < 0.001). Resin embedment also had significant effect on artifact volume (P = 0.028), while cover screw had not (P > 0.05). Non-embedded implants with the axis parallel to X-ray source of micro-CT produced minimal artifact., Conclusions: Implant angulation and resin embedment affected the artifact volume of micro-CT scanning for implant, while cover screw did not., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: The aim of the study was to investigate the dose-dependent effect of radiation on dental implant stability and osseointegration using a series of quantitative analyses., Material and Methods: Six rabbits were randomly assigned to 15 and 30 Gy radiation groups. Each rabbit received radiation at the tibial and femoral metaphyseal region of left hind leg. The right leg was used as control. Implant surgery was performed on tibial and femoral metaphyses after 1 week. Totally 24 implants were inserted. The animals were killed at postoperative week four. Implant stability was measured using resonance frequency analysis. Ratio of bone volume to total volume (BV/TV), rate of bone growth, and bone-to-implant contact (BIC) were assessed using micro-computed tomography (micro-CT), fluorochrome labeling analysis, and histomorphometric analysis, respectively., Results: After 4 weeks of healing, all implants were integrated (n = 6). Implant stability was significantly compromised by 15 Gy (P = 0.010) and 30 Gy (P = 0.025) of radiation. Radiation decreased BV/TV, and the significant effect was detected at the dose of 15 Gy (P = 0.008) and 30 Gy (P < 0.001). Bone growth in osseointegration was impaired by radiation. In 15 Gy group, the radiation side showed significant lower rate of bone growth than the control side at week 3 (P = 0.001), while the undistinguishable signals on 30 Gy radiation side suggested the low rate of new bone formation at each time point. Histomorphological BIC had no significant difference between 15 Gy control side and 15 Gy radiation side. 30 Gy radiation side showed a significantly lower BIC than 30 Gy control side (P < 0.001) as well as 15 Gy radiation side (P < 0.001)., Conclusions: Implant stability and osseointegration were compromised by radiation. Radiation compromised osseointegration in a dose-dependent manner., (© 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.)

Introduction. The psychosocial and quality of life (QoL) of patients with deformed or missing ears are frequently compromised. The aim of this study is to develop innovative techniques using CAD/CAM technology in prosthetic auricular rehabilitation and provide improvement in the treatment outcomes, including their psychology and QoL. Methods. This is a preliminary clinical cohort study. Six patients requesting for auricular reconstruction were recruited and rehabilitated with implant-supported prosthesis using CAD/CAM technology. Different treatment outcomes including QoL and psychological changes were assessed at different time points. Results. A significant reduction in severity of depressive symptoms (P = 0.038) and an improving trend of satisfaction with life were found at 1 year postoperatively when compared with the preoperative findings. The domain scores in ''Body image", ''Family/friends/strangers", and ''Mood" were also significantly higher (P < 0.05) at 1 year postoperatively than 1 week postoperatively. However, only 50% of the patients wear their auricular prosthesis regularly. Conclusion. This preliminary study has confirmed that implant-supported auricular prosthesis could induce improvement in the psychology and QoL with statistically significant differences in the domains of the body image, social interaction, and mood. Our present findings can inform research design and hypotheses generation of future studies.

Oral rehabilitation after a mandibulectomy is a challenge for prosthodontists. This clinical report describes the management of a 54-year-old man, who, after a mandibulectomy, had rotation of the mandible, with a revascularized flap, followed by an implant-supported prosthesis and ceramic restorations., (Copyright © 2013 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Purpose: The aim of this study was to develop and evaluate a new stereoscopic technique for conversion of radiographic guide into surgical guide for dental implant placement., Materials and Methods: Ten partially dentate patients requiring 18 implants for tooth replacement were recruited. Radiographic guides were modified with the addition of index rods for double computed tomography scanning. Implant positions were planned with implant planning software, and the stereoscopic angulations were measured. The radiographic guides were converted into surgical guides using either a generic bench drill (Group A, n = 9) or a milling machine (Group B, n = 9). Stereolithographic surgical guides were also made for three patients (Group S, n = 5). Differences between the planned and actual angulations were tested by pair-sample t-test. Difference of mean angle deviation among groups was tested by Brown-Forsythe test. Differences were considered significant if p < .05., Results: Eighteen implant sites were successfully treated with the converted surgical guides. The mean angle deviation of Group A (1.3 ± 0.6°) was significantly greater than Group S (0.4 ± 0.6°), while no differences were found between Group B (0.9 ± 0.3°) and Group S. The linear error was greatest in Group A with 1.5 mm at the head and 1.8 mm at the apex of the implant., Conclusions: The use of this new stereoscopic technique appears to be an acceptable alternative method for converting radiographic guide into surgical guide., (© 2011 Wiley Periodicals, Inc.)

Objectives: The aim of this study was to compare the effects of three different surface treatments in enhancing porcelain zirconia bonding., Methods: Totally, 160 densely sintered zirconia specimens were prepared and randomly divided into four study groups: control (no treatment, Group C), sandblasting (Group S), sandblasting followed by regeneration firing (Group SH), and laser irradiation (pulse mode) on a CO₂ laser system (Group L). After surface treatment, porcelain powders were veneered on zirconia surface. Half of the specimens in each group were evaluated without aging (initial shear bond strength - initial SBS), and the other half was tested after being stored in water for one month (aging SBS). X-ray diffractometry (XRD) was used to observe any crystallographic transformation at zirconia surface. Results were statistically analyzed using analysis of variance (ANOVA) and Turkey test (=0.05)., Results: The initial average SBS values of Group S, Group SH, and Group L were 31.3 ± 5.7 MPa, 29.2 ± 7.0 MPa and 32.1 ± 7.5 MPa, respectively. The differences among these three groups were not significant. The control group had significantly lower value, 24.8 ± 6.7 MPa, than those of Group S and Group L. Furthermore, there was no significant difference between initial and aging values in each group. XRD analysis showed that sandblasting caused tetragonal to monoclinic phase transformation. Regeneration firing reversed such a transformation. However, crystallographic transformation could not be detected in laser treated specimens., Significance: Both sandblasting and laser irradiation increased porcelain zirconia bond strength. The presented new modified laser pre-treatment might be an alternative way to sandblasting for improving zirconia/porcelain integration., (Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)

Objective: Alveolar distraction osteogenesis (ADO), a novel bone augmentation technique, is gaining acceptance in restoring the vertical bone discrepancy between the transplanted graft and the residual alveolar bone after mandibular reconstruction. This case series presents the outcomes of ADO in fibula-reconstructed mandibles rehabilitated with dental implants, with an emphasis on clinical indications, surgical protocol, clinical outcomes, histologic evidence, and complications., Materials and Methods: Five patients underwent fibula distraction procedures after undergoing mandibular reconstruction with a vascularized fibula bone graft. The indication for the application of ADO was for the correction of the vertical discrepancy between the top of the reconstructed fibula and the adjacent alveolar crest to achieve adequate vertical bone height before implant placement., Results: The mean vertical bone height achieved was 13.58 mm. Twenty-two dental implants were placed in 5 patients. All patients were rehabilitated with implant-supported prostheses. Bone biopsies showed the distracted area was filled with newly formed, bony trabeculae between the transported fibula and the basal segments. The most common complication was transient infection around the distractor rod., Conclusions: ADO can be performed on fibula-reconstructed mandibles to achieve the restoration of alveolar height, which then can be rehabilitated with dental implant-supported prostheses. The procedure has a minor risk of infection associated with the distractor rod, which does not compromise the bone regeneration from distraction. Patients with mandibles reconstructed with fibulas can attain dental implant rehabilitation with ADO, achieving good esthetic and occlusal outcomes., (Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

This study was to validate a mandarin Chinese version of Oral Health Impact Profile (OHIP-49) in China and to develop a shortened version of OHIP appropriate for use in partially dentate patients with implant-supported prostheses. The original 49 items of OHIP were translated into mandarin Chinese using a forward-backward method and administered to 580 subjects selected by stratified random sampling. Self-perceived oral health status and treatment need were also collected. Reliability and validity of the Chinese version of OHIP (OHIP-C49) were validated. A shortened version (OHIP-I) was derived from the OHIP-C49 by exploratory factor analysis (EFA) as well as expert-based approach in partially dentate patients (n=102) with implant-supported prostheses. For validation of the new modified shortened version, another independent sample of 97 partially dentate patients completed OHIP-I and their self-perceived oral health status at baseline and at least 3 months after dental implant rehabilitation. Five hundred and thirty-seven effectual questionnaires were reclaimed from the 580 subjects interviewed. Cronbach's alpha ranged from 0.78 to 0.96 and test-retest correlation coefficients ranged from 0.84 to 0.97 for subscale and summary scores. Construct validity was demonstrated by priori hypothesised associations between the OHIP-C49 scores and self-perceived oral health (P<0.001). The reliability and validity of OHIP-I were similar to which of the OHIP-C49, and the responsiveness appeared able to measure the effect of dental implant therapy effectively. The mandarin version of OHIP-49 showed sufficient psychometric properties for Chinese. The modified shortened version (OHIP-I) may be appropriate for the evaluation of implant therapy outcomes in partially dentate Chinese patients., (© 2012 Blackwell Publishing Ltd.)

Purpose: To investigate the changes in salivary function and oral health-related quality of life for patients with nasopharyngeal carcinoma treated by intensity-modulated radiotherapy (IMRT)., Methods and Materials: A total of 57 patients with early-stage nasopharyngeal carcinoma received IMRT. The parotid and whole saliva flow was measured, and the Medical Outcomes Study 36-item short form, European Organization for Research and Treatment of Cancer Quality of Life questionnaire-C30, European Organization for Research and Treatment of Cancer Quality of Life questionnaire 35-item head-and-neck module, and Oral Health Impact Profile questionnaires were completed at baseline and 2, 6, 12, 18, and 24 months after IMRT., Results: Parotid saliva flow recovered fully after 1 year and maintained. Whole saliva flow recovered partially to 40% of baseline. A general trend of deterioration in most quality of life scales was observed after IMRT, followed by gradual recovery. Persistent oral-related symptoms were found 2 years after treatment., Conclusion: IMRT for early-stage nasopharyngeal carcinoma could only partially preserve the whole salivary function and oral health-related quality of life., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Nasopharyngeal carcinoma (NPC) is a solid tumor closely associated with Epstein-Barr virus (EBV) infection. The purpose of this investigation was to detect and quantify the EBV DNA level in salivary samples of NPC patients following treatment using real-time PCR. A total of 175 consecutive newly diagnosed NPC patients' whole saliva samples were collected before treatment, and the EBV DNA level was measured by real-time PCR, with the primers and probe targeting the BamHI-W region of the EBV genome. The post-treatment salivary EBV DNA level was also assessed in 46 patients. The change of EBV DNA level before and after treatment and relationship of EBV DNA level to demographic data and tumor staging were tested by Wilcoxon signed-rank test and Mann-Whitney U test, respectively with the level of significance set at 0.05. The EBV detection rate of pre-treatment saliva samples was 80%. The EBV DNA level of post-treatment saliva samples was significantly higher than the pre-treatment ones (P<0.01). There is a trend that patients with advanced-stage showed a higher EBV DNA level than patients with early-stage. The detection of EBV DNA in saliva using real-time PCR might be a feasible and non-invasive method for early diagnosis of NPC., (Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.)

Amelogenesis imperfecta is a genetic disorder that causes defective enamel development in both the primary and permanent dentitions. Significant tooth structure damage often results in various pulpal symptoms, occlusal disharmony, impaired function, and esthetic disfigurement. These problems pose great challenges to the clinician when rehabilitating patients with amelogenesis imperfecta. This case report describes an uncomplicated and logical way to reorganize, temporize, and completely restore an extensively damaged dentition caused by amelogenesis imperfecta.

Objective: To describe the dental implant practice profile of Hong Kong general dental practitioners in 2008 and the trend since 2004., Materials and Methods: A self-administered questionnaire was mailed to 630 dentists through systematic sampling of registered dentists., Results: A total of 290 completed questionnaires were returned (response rate, 53%). Implant dentistry was practiced by 61% of the respondents. The survey also revealed that 84% of those respondents who own their private practice performed implant dentistry. About half of the dentists (49%) who performed implant dentistry placed or restored 5 or more implants per quarter. Among those dentists not practicing implant dentistry, the majority (85%) were interested in attending continuing education courses in dental implantology., Conclusion: There has been a significant increase in the number of general dental practitioners practicing implant dentistry in Hong Kong since 2004. By 2008, more than half of the general dental practitioners (61%) are practicing implant dentistry. Most of them not practicing implant dentistry expressed a desire to learn more about dental implants. This survey revealed a high demand for continuing professional development in implant dentistry in Hong Kong.

Purpose: The aim of this study was to compare the relative accuracy of the ridge-mapping method against that of standard computed tomography (CT)., Materials and Methods: Consecutive partially edentulous subjects requiring dental implants were recruited for this prospective study. Vacuum-formed radiographic templates with reference points were used for the ridge-mapping procedure and CT scanning. Ridge-mapping measurements were translated onto study models, which were subjected to CT scanning with the templates in place. CT images of the study models obtained from the ridge-mapping method were compared with CT images of the subjects. The data were analyzed with the Wilcoxon signed-rank test. Differences were considered significant if P < .05., Results: Fourteen subjects were recruited and a total of 21 implant sites were evaluated. The ridge dimensions measured by the bone-mapping method and CT scanning were significantly different (P < .05). The mean difference ranged from 0.3 to 0.5 mm, and large variations were found in the sulcus region., Conclusion: Measurements of the alveolar bone dimension using the ridge-mapping method are different from CT scanning, with a mean difference of about 0.4 mm.

There is limited knowledge about the changes that proximal contacts between implant-supported prostheses and adjacent teeth undergo over time. This report describes the management of a clinical situation with the loss of proximal contact between implant-supported prostheses and adjacent natural teeth in a partially edentulous patient., (Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Prosthodontic rehabilitation of a surgically resected/reconstructed jaw with a conventional tissue-borne dental prosthesis is often challenging, if not impossible, because of the suboptimal conditions of the soft and hard tissue topography/architecture of the reconstructed site. Placing dental implants in grafted bone to provide appropriate support, stability, and retention for prosthodontic rehabilitation offers the potential for improved oral function. There are, however, some clinical conditions for which an implant-supported removable prosthesis may be preferred to a fixed implant prosthesis. This clinical report describes the design and fabrication of a milled bar and a tooth- and implant-supported removable dental prosthesis for oral rehabilitation of a reconstructed mandible, which considers patient factors associated with oral and financial conditions, ease of oral hygiene procedures, and long-term maintenance., (Copyright 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Early loss of magnetic keepers in cast gold posts is seen in clinical practice., Purpose: The purpose of this vitro study was to investigate the effect of burn-out temperature on the retention of magnetic keepers in cast gold alloy and on the thickness of the oxide layer at the keeper-alloy interface., Material and Methods: One hundred and five keepers (Magfit EX) were cast with gold alloy (Protor 3) at 3 different burn-out temperatures: 500 degrees C, 600 degrees C, or 700 degrees C (n=35). To test for retention of keepers, 60 specimens (n=20) were tested to failure in tension mode in a universal testing machine (UTM); 45 specimens (n=15) were sectioned, and the interface was evaluated under a scanning electron microscope (SEM). Tensile force data were analyzed with 1-way ANOVA, and SEM data were analyzed with 1-way repeated measures ANOVA. Bonferroni multiple comparisons were performed for post hoc analysis (alpha=.05)., Results: Retention of the keepers was significantly higher at lower burn-out temperatures (P<.001). The retention of the keepers became unpredictable and immediate failures were observed at a burn-out temperature of 700 degrees C. Oxide formation at the keeper-alloy interface was significantly less at lower burn-out temperatures (P<.001)., Conclusions: A burn-out temperature of 500 degrees C for casting the Magfit EX keeper with type IV high-strength gold alloy is recommended.

Purpose: The objective of this study was to qualitatively investigate the effect of the burn-out (mold) temperature, investment material, and casting alloy on the surface integrity of the Magfit EX keeper., Materials and Methods: Forty-two Magfit EX keepers were waxed-up, invested in five investment materials (Beauty-Cast, Cristobalite, CM-10, Cera-Fina, Castorit-super), and subjected to burn-out temperatures ranging from 450 to 700 degrees C at intervals of 50 degrees C. The keeper samples were then cast into copings with three alloys (Castwell, Protor 3, Optimum) under standard conditions. The keeper surfaces were then examined under a microscope, and the compositions were assessed by an X-ray micro-analyzer in a scanning electron microscope (SEM). A new keeper served as control., Results: At a burn-out temperature of 550 degrees C, the keeper surface started to disintegrate. X-ray micro-analysis showed an increase in oxygen content with increasing temperature. At 700 degrees C, the keeper surface disintegrated, and the composition differed markedly from that of the new keeper. The keeper surfaces were intact with all investments except those with Beauty-Cast. The keeper surfaces were found to be damaged when the casting alloy was Optimum., Conclusions: Beauty-Cast investment with a burn-out temperature of 700 degrees C is unsuitable for casting the Magfit EX keeper-coping unit. Also, high fusing alloys are not recommended for casting Magfit EX keepers.

Background: Radiotherapy (RT) promises optimistic results in the treatment of nasopharyngeal cancer (NPC). The objective of the current study was to map out prospectively the impact of NPC and RT on patients from diagnosis to 1 year posttreatment., Methods: For this study, 67 Chinese patients (46 men and 21 women) with newly diagnosed stage I or II NPC who received primary RT were recruited. Physical and psychosocial adjustments were measured by using the Rotterdam Symptom Checklist, Beck Anxiety Inventory, Beck Depression Inventory, Perceived Stress Scale, and the 36-item Short-Form Health Survey (SF-36). Semistructured clinical interviews were conducted at bimonthly intervals from pre-RT to 1 year post-RT., Results: Physical and psychosocial adjustments were poorest from pre-RT to the end of RT. Rapid improvements in all areas were noted in the first 2 months post-RT and reached a plateau at around the 6th month. At 1 year, except for physical symptoms and perceived stress, patient measures recovered to their pre-RT levels. At 1 year, patients had more physical complaints (P < .001) but less perceived stress (P = .002). The percentage of patients who expressed fear of dying dropped from 28% pre-RT to 2% at 1 year. However, patients who expressed "fear of the worst happening" increased from 51% pre-RT to 57% at 1 year., Conclusions: Different periods in treatment of NPC imposed different psychosocial demands on patients. The current results indicated that the period from diagnosis to 2-month post-RT was a high-risk period both physically and emotionally. After treatment, most patients showed resilience despite persistent side effects of RT and successfully resumed their pretreatment level of functioning by the end of the year. Despite resuming a normal or near-normal living, patients still noted a subdued fear of recurrence., ((c) 2007 American Cancer Society.)

Purpose: To compare directly the effect of intensity-modulated radiotherapy (IMRT) vs. conventional radiotherapy (CRT) on salivary flow and quality of life (QoL) in patients with early-stage nasopharyngeal carcinoma (NPC)., Methods and Materials: Fifty-one patients with T2, N0/N1, M0 NPC took part in a randomized controlled clinical study and received IMRT or CRT. Stimulated whole (SWS) and parotid (SPS) saliva flow were measured and Medical Outcomes Short Form 36 (SF-36), European Organization for Research and Treatment of Cancer (EORTC) core quetionnaire, and EORTC head-and-neck module (QLQ-H&N35) were completed at baseline and 2, 6, and 12 months after radiotherapy., Results: Forty-six patients (88%) were in disease remission 12 months after radiotherapy. At 12 months postradiotherapy, 12 (50.0%) and 20 patients (83.3%) in the IMRT group had recovered at least 25% of preradiotherapy SWS and SPS flow respectively, compared with 1 (4.8%) and 2 patients (9.5%), respectively, in the CRT group. Global health scores showed continuous improvement in QoL after both treatments (p < 0.001). However, after 12 months subscale scores for role-physical, bodily pain, and physical function were significantly higher in the IMRT group, indicating a better condition (p < 0.05). Dry mouth and sticky saliva were problems in both groups 2 months after treatment. In the IMRT group, there was consistent improvement over time with xerostomia-related symptoms significantly less common than in the CRT group at 12 months postradiotherapy., Conclusions: IMRT was significantly better than CRT in terms of parotid sparing and improved QoL for early-stage disease. The findings support the case for assessment of health-related QoL in relation to head-and-neck cancer using a site-specific approach.

Background: Xerostomia is a ubiquitous complication after conventional radiotherapy for nasopharyngeal carcinoma (NPC) that seriously impairs patient quality of life (QOL). The effect on QOL of parotid-sparing intensity-modulated radiotherapy (IMRT) for early-stage NPC was assessed prospectively., Methods: Thirty-two patients with T1-2,N0-1,M0 NPC received IMRT. Saliva flow was measured, and the Medical Outcomes Short Form 36 (SF-36), European Organization for Research and Treatment of Cancer (EORTC) core, and EORTC head and neck module (QLQ-H&N35) questionnaires were completed at baseline and 2, 6, and 12 months after IMRT., Results: Saliva flow recovered to at least 25% of baseline in most cases after 1 year. Physical function, fatigue, and vitality were problems at 2 months and then resolved (p < or = .002). Global health scales showed continuous improvement in QOL after treatment (p < or = .004). Xerostomia and sticky saliva were problems 2 months after treatment; thereafter, continuous improvement occurred (p < or = .001). Xerostomia scores correlated with general aspects of QOL (p < or = .044)., Conclusion: IMRT for early-stage disease preserved key aspects of QOL, and a reduction in xerostomia symptoms enhanced broader aspects of QOL.

Aim: To investigate the oral health of elderly stroke survivors on discharge from hospital into the community after rehabilitation and six months later compared with community dwelling elderly people without stroke., Method: The study took place in the rehabilitation unit of a general medical hospital in Hong Kong. It was a longitudinal study involving 43 elderly survivors of mild to moderate stroke about to be discharged from hospital after rehabilitation and a comparison group of 43 community-dwelling elderly people. Verified clinical examination techniques and measures were used to assess dental caries, periodontal disease, oral hygiene, oral candidiasis, prosthetic status/need and functional disability (Barthel Index [BI]). Socio-demographic information was also collected., Results: Stroke survivors had significantly higher plaque and bleeding scores on hospital discharge and after six months compared with the control group (p<0.01). On hospital discharge, the stroke group also had a poorer periodontal condition with more 4-5mm pockets. The mean BI on hospital admission was 71 and 91 on discharge. Stroke survivors with a higher BI on discharge had lower plaque scores after six months. The tooth condition, number of functional tooth pairs, prosthetic status, presence of oral candidiasis and oral yeast carriage were similar between stroke and comparison groups., Conclusions: Despite significant objective improvement in functional ability after stroke, elderly survivors returning to the community had significantly poorer periodontal health compared with community dwelling elderly without stroke, and the situation did not improve dramatically over six months. The protracted recovery of hand, arm and oral sensori-motor function is the most likely cause.

Management of radiotherapy-related xerostomia is difficult. Saliva substitutes are helpful but the effects are short-lived. The purpose of the study was to develop a prototype intra-oral lubricating device for the management of radiotherapy-related xerostomia and to evaluate patient acceptance. An intra-oral lubricating device was fabricated that incorporated a reservoir in the palatal vault and permitted slow release of saliva substitute by the patient. Preliminary clinical testing was done in five patients with radiotherapy-related xerostomia. A measure incorporating seven questions was used to explore patient acceptance. The device was simple to fabricate using materials available in a technical laboratory. All patients were able to wear the device for at least 4 h per day throughout the test period. The device was considered easy to use and clean. Some impairment of speech and chewing was noted although this appeared to be related to the bulkiness of the reservoir. General oral comfort was improved due to the lubricating effect. The bulk of the reservoir was reduced as a consequence of patient feedback. The design addressed key problems associated with previous lubricating systems. Patient reports on oral functioning with the device in situ provided pivotal information on the device's utility.

The study aimed to investigate oral health-related quality of life (OHR-QoL) of stroke survivors on hospital discharge after rehabilitation. It was a cross-sectional study involving 43 elderly survivors of mild to moderate stroke about to be discharged from hospital after rehabilitation and a comparison group of 43 community-dwelling elderly people. The Medical Outcomes Short Form 36 (SF-36) measure, the General Oral Health Assessment Index (GOHAI) and an oral health transition scale were administered prior to a dental examination. Median SF-36 subscale scores were significantly different between groups (P < 0.05). In physical function, role-physical, role-emotional and mental health domains, stroke survivors had significantly lower scores indicating poorer health. The median GOHAI score for the stroke group was 52 and 54 for the comparison group with no significant difference between groups although more stroke survivors had difficulty speaking compared with the comparison group. About 75% of stroke survivors considered their appearance to be worse, half of them felt that speech was worse and about a third had difficulty chewing hard food compared with the pre-stroke condition (P < 0.05). Most participants were partially dentate with no significant difference in DMFT scores or prosthetic status between groups (P > 0.05). Health-related quality of life in general was significantly poorer after stroke although patients were considered physically well enough to be discharged from hospital. There was some impairment of OHR-QoL. The nature of the stroke, the hospital environment including diet, coping strategies and elderly Chinese peoples' perception of health should be taken into account when interpreting measures of health status in stroke survivors.

The soft tissue profile created around a conventional healing abutment may be inadequate to accommodate an anatomically shaped abutment that is larger than a standard machined abutment. This causes difficulties in its insertion and subsequent impression-making and provisional restoration fabrication. This article presents a simple technique to overcome these problems.

Background: Xerostomia is a uniform complication after radiotherapy (RT) for nasopharyngeal carcinoma (NPC). Dosimetric studies suggested that intensity-modulated RT (IMRT) can spare part of the parotid glands from high-dose radiation. Disease control and salivary function after IMRT for early-stage NPC was studied prospectively., Methods: Thirty-three patients with T1,N0-N1,M0 NPC were treated with IMRT from 2000 to 2002. The prescribed dose was 68-70 grays (Gy) in 34 fractions to gross tumor volume, 64-68 Gy to the planning target volume, and 70 Gy to enlarged cervical lymph nodes. Nineteen patients had stimulated whole salivary (SWS) flow assessment and stimulated parotid salivary (SPS) flow assessment at baseline and at 2 months, 6 months, 12 months, 18 months, and 24 months after the completion of IMRT., Results: At a median follow-up of 2 years, only 1 neck failure was observed. The 2-year and 3-year local control, distant metastases-free, and overall survival rates all were 100%. The lymph node control and progression-free survival rates were 100% at 2 years and 92.3% at 3 years, respectively. The average mean dose to the parotid gland was 38.8 Gy. The SWS and SPS flow showed continuous recovery: 60% and 47.1% of patients recovered at least 25% of their baseline SPS flow and SWS flow, respectively, at 1 year after completion of IMRT, and the proportions rose to 85.7% and 71.4%, respectively, by 2 years. The pH and buffering capacity of saliva also improved with time., Conclusions: Parotid-sparing IMRT achieved good locoregional control, and there was continuous recovery of salivary flow, pH, and buffering capacity in the first 2 years after IMRT in patients with NPC., ((c) 2004 American Cancer Society.)

Although the complications of head and neck radiotherapy in the treatment of nasopharyngeal carcinoma (NPC) have been described, there is limited information on the effect of oral complications on oral health related quality of life. The aim of this study was to describe the psychosocial and functional impact of oral conditions in southern Chinese following radiotherapy for NPC. A cross-sectional study design was used with a sample of 109 subjects including NPC survivors, newly diagnosed NPC cases and a control group. Oral health related quality of life was assessed through the SF-36 and the Oral Health Impact Profile measures and a dry mouth measure. Data on socio-demographic variables and treatment seeking were also collected. The psychosocial and functional impact of oral conditions as revealed by the health status measures was significantly greater in NPC survivors than newly diagnosed NPC cases and controls. The oral specific and condition specific measures appeared to discriminate more effectively between groups than the generic measure. NPC survivors sought significantly more dental treatment than the other groups. The oral complications of radiotherapy for NPC, notably sequelae of salivary gland damage, have a significant negative effect on oral health related quality of life and result in an increased burden of dental care in the long-term.

The casting of extensive implant superstructures that have a good passive fit may be technically demanding. A simple, 2-stage casting technique is presented that avoids common problems associated with the casting of large superstructures. The fabrication of a 7-unit metal-ceramic screw-retained fixed partial denture supported by 5 implants is used to illustrate this technique.

Nasopharyngeal carcinoma (NPC) is rare among Caucasians but very common among southern Chinese. No information is presently available on the relationship between salivary gland function and xerostomia in irradiated southern Chinese. Salivary gland function and xerostomia were measured in irradiated NPC patients, recently diagnosed NPC patients, and a matched control group. Stimulated whole saliva was collected from each participant and flow rate, pH and buffer capacity measured. All participants completed a multi-item dry mouth questionnaire. Comparisons were made using Chi-square and Mann-Whitney tests and correlations assessed using Spearman's rank correlation coefficients. The mean saliva flow rate and pH were significantly lower and the buffer capacity impaired in irradiated NPC patients compared with the other groups ( P<0.01). Significantly more irradiated NPC patients had negative impacts associated with dry mouth generally, sticky saliva, and hoarse voice ( P<0.01). Subjective dry mouth symptoms and associated reduced saliva flow were also relatively common in non-irradiated participants. Salivary gland hypofunction and xerostomia were major complications in irradiated NPC patients. In irradiated and non-irradiated southern Chinese, subjective dry mouth symptoms appeared to be correlated with actual salivary gland function.