The convenience of gathering evidence is enhanced by three-dimensional (3D) scanner and printer technologies, however they also raise the risk of creating false evidence. The purpose of this study is to analyze the accuracy of bite marks obtained from digital dental models using quantitative methodologies, as well as to investigate the potential for bite marks obtained from models manufactured using 3D printing technology to produce false evidence. Between the ages of 18 and 25, 15 volunteers who had not undergone orthodontic treatment and had a class I skeletal relationship were included in the study and maxillary impressions were taken with an intraoral scanner (IOS). Maxillary models were produced with a 3D printer from digital impressions. Using dental silicone and dental wax materials often used by forensic odontologists, bite marks were obtained from both volunteers and their 3D models. Similarity analysis of bite marks was performed using the superimposition method using a 3D surface matching software program (Geomagic Control X 2020; 3D System). Following superimposition, RMS (Root Mean Square) values were calculated and utilized for comparison. The bite marks from participants differed significantly from those from 3D printed models (P < .05). While bite marks obtained from 3D printed models first looked to be identical to the actual marks, digital scanning and superimposition analysis revealed significant variances. Advancements in 3D printing technology, as well as their ease of use, may enhance the possibility of evidence fabrication. While this study demonstrates that there are discernible distinctions between actual bite marks and artificials, consistent techniques are required to improve the trustworthiness of digital data in forensic odontology.

ABSTRACT Introduction: Intravaginal-based brachytherapy treatment is highly useful in the treatment of gynecological malignancies. A common challenge to come across in intravaginal application is achieving 100% of dose prescribed in vaginal vault region during the brachytherapy treatment course. In the superior part of the intravaginal applicator, the vaginal vault area receives a lesser dose as compared to the vaginal walls due to the dip in the 100% dose coverage in the vault region. This could be a potential factor contributing to the vaginal vault recurrence in cervical cancer and endometrial cancer. Aim: The aim of this study is to improve the dose coverage of the vaginal vault area using an indigenously developed improvised intravaginal wax applicator. Materials and Methods: Dental wax is melted and made a replica of the company-provided applicator. The dose is measured using film dosimetry, and dose distribution is studied at distal end of the applicator (vaginal vault region). Results and Discussion: The applicator is able to produce uniform dose coverage around the distal end and along the sides at 5 mm from the applicator surface. This study shows that the under dosage at the vaginal vault area can be rectified using this indigenously developed improvised intravaginal wax applicator. The process explained here is economically affordable, and the materials used are easily available. Conclusion: With the help of indigenously developed improvised intravaginal wax applicator, 100% dose is achieved with much lesser radio toxicity.

BackgroundA serious game module called “D-Casting” was developed in the previous study. This study aimed to determine the effectiveness of the D-Casting module.MethodsThe experiment consisted of two parts: construct validity assessment and skill transfer assessment. Eligible participants, who were students majoring in dental and dental technology, were recruited from the Stomatology College of Chongqing Medical University. The intervention was designed based on the serious games assessment framework.ResultsThe construct validity assessment recruited a total of 145 participants (100% response rate). The results suggested that D-Casting module could effectively distinguish novice and experienced students (86.67[15.832] vs. 88.62 [11.252] vs. 82.24 [15.674] vs. 96.39 [8.419]; P < 0.001). The skill transfer assessment recruited a total of 78 participants (100% response rate). This assessment showed that the group combined with D-Casting for teaching and learning performed better than the control group in the casting process (82.26[13.711] vs. 89.64[6.796]; Z = -2.033; P = 0.042). The simple mediation analysis showed that the direct effect from the instructing method to the scores of the casts was not significant (95% CI − 3.45 to 2.98), but the indirect effect (95% CI 3.42 to 12.39) and total effect from the instructing method to the scores of the casts (95% CI 2.50 to 12.27; P = 0.004) were significant.ConclusionThis study determined construct validity and the skill transfer situation for the D-Casting module. Further multi-center experiments should be conducted to determine how skills are transferred through serious games.

Although dental patterns are unique, the use of bitemark analysis in personal identification remains controversial. To accurately reproduce and compare three-dimensional models of bitemarks and dental arches, intraoral three-dimensional scans, commonly utilized in clinical dental practice for precise and stable digital impressions, are recommended. This study aims to compare two different techniques for bitemark analysis: a digital method based on the superimposition of digital scans of dental patterns and lesions, and a visual method based on the physical superimposition of impressions and resin casts produced by 3D printing. A sample of 12 volunteers (6 males and 6 females) with a mean age of 26 years was collected as biters. Each subject was asked to bite on custom supports made from semi-rigid water bottles covered with imprintable dental wax. The dental arches and bitemarks were then recorded using an intraoral scanner and dental impressions. Scan superimposition analysis was conducted using CloudCompare software, while resin casts were printed using a 3D printer and physically superimposed on the bitemark impressions by a blind operator, who was not involved in sample collection, bite test execution, prior cast acquisition, or CloudCompare analysis. Both superimposition techniques relied on the selection of 10 corresponding landmarks (on canines and central and lateral incisors of the upper and lower arches) between the dental arches and impressions. The digital superimposition showed an average concordance of 92.5% for the upper arch landmarks and 85% for the lower arch landmarks, with an overall average concordance of 88.8% for both arches combined. In contrast, the visual analysis of resin casts showed an average concordance of 77.5% for the upper arch and 76.7% for the lower arch, with an overall average of 77.1% for both arches combined. In the analysis performed using CloudCompare, the maxillary arch demonstrated the best superimposition, with 4 landmarks (R0, R1, R2, R5) consistently overlapping. The digital analysis outperformed the visual analysis in all four quadrants, particularly in the upper right arch compared to the lower left arch, thereby supporting the integration of digital techniques in forensic applications. Further studies are necessary to validate the digital technique on a larger sample, including subjects with different dental characteristics, bite dynamics, and varying types of supports and substrates.

The study was performed to examine the error associated with image superimposition when computed tomography (CT) images of the dental region are substituted with dental scan data, according to the block-out material used in dental impressions. A typodont model was created by bonding orthodontic brackets to teeth on plaster dental stones using melted dental base-plate wax. In the experiment, 2 groups were compared: one using wax and the other using putty as the block-out material to prevent tearing of the impression material during the acquisition of dental impressions. In the wax group, dental cast digital data were superimposed onto the CT data of the typodont model using a tooth occlusal surface-based registration method. In the putty group, a surface-based registration method was used that incorporated not only the occlusal surfaces of the teeth, but also the area where the radiopaque putty covered the orthodontic brackets. The absolute value of the error on the dental surfaces was measured for comparisons. Analysis of the scanned areas used for replacement in dental CT images revealed fewer superimposition errors when considering only the tooth occlusal surface area, excluding the area containing putty impression material. The clinical recommendation is to block out the orthodontic bracket with radiolucent wax when obtaining dental impressions. Furthermore, only dental occlusal surface-based registration should be used for the superimposition and replacement of the CT image of the dental area with scanned data from a dental cast model.

Digitally-designed removable complete dentures are typically composed of a resin denture base without a metal framework. However, metal denture bases are preferable as resin bases are more susceptible to fracture. Therefore, this article introduces a unique technique that integrates computer-aided design (CAD) and conventional resin processing for the fabrication of removable complete dentures with a metal framework. A maxillary complete denture with a metal base and a mandibular implant-retained overdenture reinforced with a metal framework were fabricated. The dentures were designed using CAD software and a tooth library. The denture bases were milled from wax disks, and artificial teeth were placed to complete the wax dentures. The metal frameworks were also designed using CAD software and produced via casting of printed resin patterns. Finally, conventional denture processing techniques were applied to obtain dentures with metal frameworks. A digitally designed, removable complete denture with a metal base can be successfully fabricated using the described technique, which merges digital design and conventional methods. This article demonstrates the feasibility and potential advantages of this innovative approach in denture fabrication. The presented technique provides the following advantages: digital design features, precise space above implant overdenture attachments for a metal framework, convenience of esthetic evaluation with printed trial dentures, long-term data storage and duplication, reliable bond between the artificial teeth and denture base, and enhanced strength of the removable complete denture due to the metal reinforcement.

Aim: To evaluate the potential of inducing mineral density changes of indirect pulp capping materials applied to demineralized dentin. Methods: A total of 50 cavities were prepared, 5 in each tooth, in extracted ten molars without caries, impacted or semi-embedded. The cavities were scanned by microcomputed tomography (μ-CT) after creating artificial caries by microcosm method (pre-treatment). Each cavity was subjected to one of 5 different experimental conditions: control (dental wax), conventional glass ionomer cement (Fuji IX GP Extra), resin-modified calcium silicate (TheraCal LC), resin-modified calcium hydroxide (Ultra-Blend Plus), MTA (MM-MTA) and the samples were kept under intrapulpal pressure using simulated body fluid for 45 days. Then, the second μ-CT scan was performed (post-treatment), and the change in dentin mineral density was calculated. Afterward, elemental mapping was performed on the dentinal surfaces adjacent to the pulp capping agents of 5 randomly selected samples using energy dispersive X-ray spectroscopy (EDS) apparatus attached to a scanning electron microscope (SEM). The Ca/P ratio by weight was calculated. Friedman test and Wilcoxon Signed Ranks test were used to analyze the data. Results: There was a significant increase in mineral density values of demineralized dentin after treatment for all material groups (p&lt;0.05). Resin-modified calcium silicate had similar efficacy to MTA and conventional glass ionomer cement, but was superior to resin-modified calcium hydroxide in increasing the mineral density values of demineralized dentin. Conclusions: Demineralized dentin tissue that is still repairable can be effectively preserved using materials with remineralization capability.

Temporomandibular disorders (TMD) are one of the leading health problems in dentistry. The work aimed to evaluate, using FEM, the influence of the material elastic properties of the flexible obstacle of the tongue trainer on the range of deflection and strength.In prototyping the trainer tongue, the starting point was real models with different extents of the tongue obstacle. moulded from dental wax on a dental stone model. Then versions were tested intraorally for the perception of the space occupied by the tongue. The models were scanned on a 3D scanner, and then a parametric CAD model (NX Siemens) was made on their basis. Finally, in order to take into account, the anatomical aspects, the two extreme ranges of the tongue obstacle, named "Long " and " Short ", were developed. Simulation deflection and material strength tests were made using FEM in the linear range (NX Siemens). Calculations were made for materials with Young's modulus equal to 8 MPa, 80 MPa and 800 MPa. The interaction of the tongue with the force of 5N was assumed. The support was provided by the retention surface on the teeth, with the support of the posterior edge of the obstacle on the palate (palatal variant) or lack of support, i.e., the obstacle freely bending in this area (free variant), was additionally tested. In order to assess the drop or retention of the trainer on the teeth, the second type of simulation was performed with the assumption of horizontal (anteriorly directed) tongue pressure with the force of 10N for the condition of rigid support in the area of the teeth and the periodontal zone from the lingual side. In this variant, a simulation was adopted for a material with a modulus of elasticity E=80 MPa.The stress values of the flexible obstacle of the trainer were obtained, allowing for the selection of potentially valuable materials for the trainer's construction. The results obtained in the simulations indicate the possibility of using ethylene vinyl acetate (EVA) and its blends. The accumulation of saliva inside the sealed obstacle was found, which indicated the need to look for an area to perforate without losing the load capacity of the obstacle. The structural feasibility of solving the problem of saliva accumulation without a significant change in the load capacity and stiffness of the obstacle was confirmed by simulation.Simplifying the model to a linear range does not allow buckling analysis. In addition, the assumption of a linear material further limits the possibility of analysing materials with softening and plateau characteristics, where the compliance of the structure leads to elastic buckling.The range of deflections and stresses for different stiffness of the elastic element of the trainer was determined in order to select the appropriate material for the medical device (MD). Polyurethanes or silicones provide the range of deflection and strength, but in the case of manufacturing prefabricated trainers thermoformed in the patient's mouth (maximum temperature 75C), the material that can be used is ethylene vinyl acetate (EVA).Simulation tests made it possible to determine the range of deflections and stress for different stiffness of the flexible obstacle of the trainer in order to select the appropriate material for the medical device.

A radiotherapy bolus is a tissue-equivalent material placed on the skin to adjust the surface dose of megavoltage X-ray beams used for treatment. In this study, the dosimetric properties of two 3D-printed filament materials, polylactic acid (PLA) and thermoplastic polyether urethane (TPU), used as radiotherapy boluses, were investigated. The dosimetric properties of PLA and TPU were compared with those of several conventional bolus materials and RMI457 Solid Water. Percentage depth-dose (PDD) measurements in the build-up region were performed for all materials using 6 and 10 MV photon treatment beams on Varian linear accelerators. The results showed that the differences in the PDDs of the 3D-printed materials from the RMI457 Solid Water were within 3%, whereas those of the dental wax and SuperFlab gel materials were within 5%. This indicates that PLA and TPU 3D-printed materials are suitable radiotherapy bolus materials.

This paper aims to present a new method for surface treatment of open pore materials and specimens to aid and fasten the segmentation process. The study is divided into two parts. In the first part of the investigation, three materials were tested on a plastic surface under laboratory conditions: X-ray contrast dental adhesive, wax, and zinc spray. After careful observation of the results, the zinc spray was selected for the purposes of the study. In the second part, the experiment was repeated with zinc contrast layers on a single-rooted tooth in two and three layers, zinc spray on sintered glass and a multirooted tooth in three layers. Region growing method was selected for the segmentation. The selected specimens were covered with a contrast layer, scanned, and images were reconstructed and analysed. After both the scanning and reconstruction stages, success was achieved in the samples with three layers. As a next step, the volumes of the root canal and the sintered glass were calculated successfully. In conclusion, using zinc spray as an X-ray contrast coating may be a successful approach in micro-computed tomography.

The purpose of this paper is to present a simple yet effective technique to reduce mucosal injuries for patients on Erich arch bar. Patients with jaw fractures and concurrent soft tissue injuries on the labial mucosa can have problems with wound healing due to constant irritation from the Erich arch bar. We found that the current practice of using dental wax is inadequate as it tends to dislodge easily. We have experimented the use of Vinyl PolySiloxane impression material as a substitute for dental wax with promising results.

Objective: To assess the cross infection control practices among undergraduates and graduates working in the department of Prosthodontics in various public and private dental colleges of Karachi.&#x0D; Methods: After approval from IRB, the self-administered questionnaire was sent via emails or social media platforms to undergraduate final year students and graduates currently working in Prosthodontics department of dental colleges of Karachi. Along with demographics, the questionnaire included close ended multiple-choice questions related to participants’ practice regarding cross infection control. A reminder was sent after 2 weeks to help improve response rate. Statistical analysis was performed using SPSS 23.&#x0D; Results: Out of total 617 respondents, there were 410(66.5%) final year dental students and 207(33.5%) house officers. Majority of participants 502(82.3%) had attended lecture regarding cross-infection control measures during their academic years, while only 178(28.8%) had attended hands-on workshops on the same. Majority 530(85.9%) recommended autoclave for sterilization for instruments. Almost all participants 603 (97.7%) wear gloves and perform hand hygiene 527(85.4%). More than two-thirds 416 (67.4%) respondents disinfect impressions, trial wax dentures, bite registrations and metal trials before sending to the dental laboratory. Almost 50% of the participants did not disinfect plastic impression trays, shade guide, rubber bowl, wax knife, carver and spatula in between patients.&#x0D; Conclusion: Results of this study highlight the need of re-emphasizing cross-infection control measures and practices in the Prosthodontics OPD. Strict administrative protocols should be set to implement cross-infection control practices. Lectures and hands-on workshops regarding cross-infection control, disinfection and sterilization should be a mandatory part of curriculum and be reiterated in continuing dental education seminars.

Background: In dentistry, different researchers in various studies have tried various methods and techniques to reuse, recycle and manage the waste of dental materials. CAD/CAM wax could be recycled effectively without any degeneration of its original properties by refreshing with new materials using simple techniques. The objective of the current study is to evaluate the dimensional accuracy of the new modified machinable dental wax for CAD/CAM purposes.&#x0D; Materials and Methods: In the present study three experimental blank discs were performed using the same technique for each type, but with different weight/compositions of dental and mineral waxes. A master die was scanned and designed for the crown copy patterns. Ten identical wax copings were milled for each experimental group (Type I, Type II, and Type III) to compare with the control (Dentify-Germany and Zotion™-China) discs. Wax patterns were cast into metal copies to assess the differences in accuracy values of the axial, proximal, and occlusal surfaces between the wax patterns and metal coping.&#x0D; Result: Non- significant differences were noticed in the thickness accuracy between the wax pattern and the metal copy of the experimental discs of Type (I) and Type (II) that were manually produced compared to the commercial discs (P&gt;0.05). While, Type III showed statistically significant differences were noticed between the wax and metal patterns, at different surfaces except in mesial surface (P&lt;0.05).&#x0D; Conclusion: Wax patterns fabricated using a new version of machinable wax produced by recycling some CAD/CAM wax with different fresh materials showed acceptable dimensional accuracy. Also, it seems to have few significant differences for CAD/CAM purposes in terms of patterns thickness than those obtained available and conventional waxTM.

More and more studies have being done on the deformation process of food and the formation of food bolus during chewing. However, it is hard to observe the food oral processing (FOP) of subjects and obtain related data directly. A bionic chewing robot based on a six-axis parallel mechanism was proposed in this paper. The robot can not only simulate the movement of the lower jaw but also set a variety of oral processing parameters, such as the number and shape of teeth, oral temperature, saliva volume, chewing cycles, speed and force. Meanwhile, dental wax and peanuts were taken as food samples, and the chewing experiments were carried out by the bionic chewing robot and subjects, respectively. The results showed that the bionic chewing robot could be used to mimic human FOP and produce food bolus. Especially when the chewing cycles met the requirement of swallowing, the median particle size of the peanut bolus and the mixing effect index of the dental wax bolus in the two different experiments were highly consistent. In addition, the robot was proved to have the same food texture detection function as the texture analyzer.

Background: The attitudes and behaviors of students after their injuries in preclinical education in the faculties of dentistry are very important in terms of blood-borne diseases and infection risks. For this reason, this study aimed to determine the injuries experienced by dentistry students in preclinical courses in detail and to determine their post-injury behaviors. Methods: The study was conducted on students who completed their first and second education years. The surveys we prepared were conducted anonymously by sending to the volunteer participants via "Google Forms". In the surveys, we questioned the types of injuries they experienced in the courses; the materials that caused the injury; the number of injuries; the time period of the course and in which preclinical training course the injuries occurred; and their behaviors after injury and their reasons. In the study, information (n) and (%) were given as descriptive statistics of the data. In the analysis of the relationship between two categorical variables, Pearson Chi-Square analysis was applied when the sample size assumption was met, and Fisher's Exact test was applied when the sample size assumption was not met. Analyzes were carried out in IBM SPSS 25 program. Results: 66% of the students (n:87) stated that they were injured at least once in pre-clinical courses. The most common injuries were cutting-penetrating (72.9 %) due to the use of dental spatula and injury from direct fire source (59.4 %) in the first-year students. Dental wires (96 %) dental explorer (78 %) and burning injuries with hot dental wax (64 %) resulted in high rates of students who completed the second year. 87.5 % of the students who completed their second year stated that they were injured mostly in the preclinical education courses of Prosthodontics. It was found that only 24 % of the students reported all their injuries. Conclusions: The high injury rates in our study revealed the inability of the students to use cutting-penetrating tools and laboratory materials safely. In addition, their attitudes and behaviors after injuries showed that blood-borne diseases and cross-infection knowledge were insufficient. In order to take precautions in these issues, students must be educated before preclinical courses.

The various pedagogical methods applied for teaching dental anatomy to dental students includes lectures, analysis of extracted natural teeth and carving of wax blocks to accurately replicate the morphology of teeth. The thorough knowledge of dental morphology is indispensable for a successful dental practice. This study was thus aimed to assess the perceived relevance of tooth carving using wax block among the dental practitioners. A cross-sectional study was designed with the objective of involving dental practitioners working in Kathmandu. Self-administered questionnaires were used for the data collection. The results were later analyzed for descriptive statistics using the Statistical Package for the Social Sciences (SPSS) 16 software. About 232 (98.3%) participants practiced tooth carving using wax block to study dental anatomy. More than 96% of the participants agreed that tooth carving exercises have helped them better understand tooth morphology and more than 85% feel that their manual dexterity was developed by these exercises. A total of 223 (94.5%) were of the opinion that tooth carving should be continued in the BDS preclinical curriculum. The dental wax carving is an effective pedagogical strategy to develop manual dexterity of dental students by recreating tooth morphological features using a wax block, thereby achieving the mandatory psychomotor skills.

Low LET radiations such as cobalt (1.25 MeV) and 6 MV linac megavoltage gamma/x radiations continue to be a basic facility in a busy radiation therapy department. When the beam profiles in water are carefully scrutinized, linac beams have flattened isodose curves compared to slightly rounded curves in Co-60 beams at all depths. It was speculated that to overcome slight non-uniformity in the edges, as well as slight variations inside the planning target volume (PTV), a beam flattening filter may be preferable to be used along with plain radiotherapy fields. A pilot study of clinical use of beam flattener in cobalt beam is reported. A flattening filter (FF) was locally made out of dental wax, for 20 x 20cm field, in the 780E Telecobalt machine (M/s MDS Nordian, Canada). Beam profiles with and without FF were measured using water phantom, to confirm the filter efficiency. Both manual and Radiation Field (RFA) methods in water phantom confirmed efficacy of wax filter. This flattened beam was used in the treatments of Uterine Cervix and Oesophagus cancers, (25 patients each) with a measured filter transmission factor 0.805 in treatment plans. All the patients completed the prescribed dose of 50Gy in 25 fractions for Ca Cervix and 50Gy/25 fractions or 50.4Gy/28 fractions for Ca Oesophagus; at 5 fractions/ week treatment regimens. Case records of these patients retrospectively verified did not reveal any untoward associated morbidity on routine clinical follow ups during treatment or immediate follow up. As multi-leaf collimated cobalt beam also has built in rounded beam profiles, outcome of this work implemented in clinical applications add to new research knowledge. As cervix, head and neck, oesophagus malignancies form significant percentage of radiation oncology treatments, results of this present work will benefit many conventional treatments. It is strongly recommended that the clinical efficacy of FF Cobalt treatments be investigated in a controlled clinical trial, by random allotments with FF plain fields, with output corrections.

HF01-04 THE WAX-TIPPED CATHETER: DIAGNOSING URETERAL AND RENAL CALCULI PRIOR TO RADIOGRAPHY

OPTICAL COHERENCE TOMOGRAPHY FOR THE DETECTION AND CHARACTERIZATION OF SUBGINGIVAL ROOT CARIES LESIONS AND NONCARIOUS CERVICAL LESIONS: A QUANTITATIVE ANALYSIS

Evaluation of the Effect of a Modified Version of Machinable Dental Wax for CAD-CAM Purposes