Digital matching of palatal rugae patterns for forensic identification in edentulous denture wearers.

Identifying edentulous victims in forensic contexts poses a significant challenge. It has been reported that having a denture to reproduce and compare Palatal Rugae (PR) patterns is crucial for identifying edentulous individuals, yet there are no validated protocols for conducting this procedure. In this study, a new method was developed and validated for plaster molding of the internal surface of upper dentures, along with a protocol involving focus-stacked photographs and reference scales. Thirty-eight edentulous subjects participated in the study, obtaining plaster models of the patients (PM), and their dentures (AM) were standardized. The AM/PM model was highlighted and photographed with ten shots in different z-focuses for each model, using standard lighting and aligning the position of the PR perpendicular to the photographic axis using tubular spirit levels and modeling clay. The images were processed using the stacking technique and analyzed by three observers through the proposed protocol using Adobe® Photoshop®. The results were analyzed based on the intra-observer and inter-observer agreement levels, with a 95% confidence interval. This study demonstrated high-precision intra-observer and inter-observer agreement (k = 1) in the matching of Palatal Rugae (PR) and maxillary morphology obtained from participants and their dentures. The protocol is simple, cost-effective, and precise. It enables standardization of the technique for obtaining plaster models, and the exposure of PR and photographic protocol minimizes the presence of artifacts in the images, thereby reducing the likelihood of errors and promoting the reproducibility of both the recording technique and the comparison of the PR.

Complete denture palatal rugae design impact on satisfaction and quality of life.

OBJECTIVES: To compare the impact of three complete denture palatal rugae designs on participants' satisfaction and oral-health-related quality of life. BACKGROUND: Complete dentures palatal rugea are usually polished to a smooth finish, which can affect the patient's adaptation. Roughening or keeping an opening in the rugae area to replicate the natural sensation of the palatal rugae has been suggested but lacks clinical evidence. METHODS: This randomised crossover trial included participants with complete dentures randomly allocated to six sequences. Each sequence alternated between polished, roughened, and open rugae designs. Participants evaluated general and domain-specific satisfaction (eating, taste, speaking, phonetics, and ease of cleaning) on a 100-mm visual analogue scale. They also completed the Oral Health Impact Profile for Edentulous Patients (OHIP-EDENT) and indicated their preferred design at the end. Repeated-measure ANOVA compared satisfaction, and one-way ANOVA with Tukey's test compared OHIP-EDENT scores. RESULTS: Forty-two participants were randomised. Seven dropped out. General satisfaction ratings were comparable for the polished (Mean = 80.2, SD = 19.7) and roughened designs (Mean = 79.5, SD = 20.2). However, the open design had a significantly lower satisfaction rating (Mean = 41.1, SD = 32.2). OHIP-EDENT scores for the open design (Mean = 44.9, SD = 17.5) were significantly worse than those for the polished (Mean = 36.1, SD = 12.7) and roughened designs (Mean = 36.2, SD = 13.3). Two-thirds of the participants chose the polished design. One-third chose the roughened design; of those, 83% were first-time denture wearers. CONCLUSIONS: Complete dentures with polished and roughened rugae designs were perceived similarly. Both designs could be recommended based on the patient's preference. However, the open design should be avoided due to negative perception.

Assessment of Palatal Rugae to Aid in Gender Identification in Hazaribag Population-A Cross-Sectional Study.

Background: This research paper aims to investigate the effectiveness of gender identification utilizing palatal rugae. Materials and Methods: The size of the sample that was selected included 100 people. They were made up of 50 men and 50 women, all in between the ages of 18 and 25. To examine their palatal rugae patterns, casts were made after taking maxillary impressions. Based on the size and rugae amount found on the left as well as the right sides, the palatal rugae patterns were investigated. Rugae patterns have been recognized based on the categorization provided by Thomas and Kotze (1983). Statistical Analysis: Chi-square analysis has been used. Results: There were comparative variations in the shape of rugae patterns among male and female individuals. The study revealed that the circular pattern was higher in males (P < 0.01) as compared to females and the unification pattern was comparatively greater in females (P < 0.05) as compared to males. The most predominant pattern that was seen in both genders was the wavy pattern that was seen to be present in 57.17% of males and 53.42% of females. The rugae number on the right and left sides did not exhibit any significant variations. Conclusions: This research thus exhibits a relevant difference in patterns of rugae and also confirms the uniqueness of patterns in each individual. Hence, it could be utilized as an adjunct to other tools for identification in the forensic sciences.

Ultrasonic mapping of midpalatal suture - An ex-vivo study.

OBJECTIVE: Rapid maxillary expansion is a common orthodontic procedure to correct maxillary constriction. Assessing the midpalatal suture (MPS) expansion plays a crucial role in treatment planning to determine its effectiveness. The objectives of this preliminary investigation are to demonstrate a proof of concept that the palatal bone underlying the rugae can be clearly imaged by ultrasound (US) and the reconstructed axial view of the US image accurately maps the MPS patency. METHODS: An ex-vivo US scanning was conducted on the upper jawbones of two piglet's carcasses before and after the creation of bone defects, which simulated the suture opening. The planar images were processed to enhance bone intensity distribution before being orderly stacked to fuse into a volume. Graph-cut segmentation was applied to delineate the palatal bone to generate a bone volume. The accuracy of the reconstructed bone volume and the suture opening was validated by the micro-computed tomography (µCT) data used as the ground truth and compared with cone beam computed tomography (CBCT) data as the clinical standard. Also included in the comparison is the rugae thickness. Correlation and Bland-Altman plots were used to test the agreement between the two methods: US versus µCT/CBCT. RESULTS: The reconstruction of the US palatal bone volumes was accurate based on surface topography comparison with a mean error of 0.19 mm for pre-defect and 0.15 mm and 0.09 mm for post-defect models of the two samples, respectively when compared with µCT volumes. A strong correlation (R2 ≥ 0.99) in measuring MPS expansion was found between US and µCT/CBCT with MADs of less than 0.05 mm, 0.11 mm and 0.23 mm for US, µCT and CBCT, respectively. CONCLUSIONS: It was possible to axially image the MPS opening and rugae thickness accurately using high-frequency ultrasound. CLINICAL SIGNIFICANCE: This study introduces an ionizing radiation-free, low-cost, and portable technique to accurately image a difficult part of oral cavity anatomy. The advantages of conceivable visualization could promise a successful clinical examination of MPS to support the predictable treatment outcome of maxillary transverse deficiency.

Minor physical anomalies including palatal rugae pattern and palatal dimensions in children with sickle cell disease: A cross-sectional analytical study.

Background: Sickle cell disease (SCD) is the most common hereditary hemoglobinopathy, which delays growth leading to an altered skeleton and craniofacial pattern. Palatal rugae patterning has been considered the regulator of the development of the palate. The purpose of the research work was to study the morphology of the palate, rugae pattern, and its dimensions in SCD children and compare them with healthy normal children, and to evaluate its role as minor physical anomalies (MPAs). Methods: A cross-sectional case-control study was designed as per STROBE guidelines. The sample comprised 50 children diagnosed with sickle cell disease (Group SCD) and 50 normal healthy children as control (Group C) belonging to the same age group (10-18 years). Dental impressions were made, followed by the pouring of dental casts. The length of the palatal rugae was measured and categorized into primary (>5 mm), secondary (3 mm-5 mm), and fragmentary rugae (<3 mm). The shape of each primary palatal rugae was identified and categorized as curved, wavy, straight, circular and non-specific. Linear and angular measurements of the palatal rugae patterns and palatal dimensions (width, height, area) were measured and recorded. Results: The total number of palatal rugae and fragmentary rugae was lesser in Group SCD than in Group C (p < 0.05). The depth of the palate was significantly increased, whereas the area of the palate significantly decreased in Group SCD. Conclusions: The children with SCD showed distinctive palatal rugae patterns and dimensions when compared with normal healthy children that can be attributed as potential MPAs for sickle cell disease. Children with SCD had an under-developed palatal rugae pattern with a deep, narrow and small palate when compared to healthy children.The dimensions of the palatal rugae pattern in SCD showed reduced distance between the incisive papilla and the first and last rugae, indicating a further decrease in the anteroposterior dimensions of the palate. These findings may aid in the early diagnosis and prevention of malocclusion in children with SCD by appropriate interceptive orthodontic treatment.

Palatal Rugoscopy: A Tool for Ethnicity and Gender Identification Among Saudi and Kuwaiti Populations.

Background The establishment of human identity has always been a concern after mass disasters, and the role of odontology in forensics has greatly evolved. Nowadays, palatal rugoscopy is a widely used method in the recognition of human identity due to its uniqueness in the course, direction, length, form, position, and enduring nature against disintegration. Its easy applicability, cost-effectiveness, and prompt results can be applied to festering, scorched bodies and in the absence of missing upper limbs and fingers. This study was undertaken to evaluate palatal rugoscopy as a tool to recognize human identity and gender between two different ethnic populations. Methodology A cross-sectional comparative study was conducted in the Department of Oral Maxillofacial Surgery and Diagnostic Sciences, Riyadh Elm University, Riyadh, Saudi Arabia, to recognize ethnicity and gender among the Saudi and Kuwaiti populations. A total of 364 participants were selected from the outpatient department between September 2022 and December 2022. All 364 participants were distributed into two groups after the application of inclusion and exclusion criteria. After obtaining informed consent from all study participants, study models were prepared for final interpretation. The outlining of rugae was done with the help of a sharp graphite pencil, and the assessment of various parameters, including total number, length, direction, unification, and shape of rugae, was done. A comparison was made between the two populations. SPSS version 26.0 (IBM Corp., Armonk, NY, USA) was employed to assess variations in the mean values of both the total number and the distribution of rugae on the right and left sides across different ethnic groups and genders. Results In this study, a total of 364 participants were included. Of the total participants, 184 were Saudis and 180 were Kuwaitis, with 188 males and 176 females. A comparative evaluation of rugae among ethnic groups showed that Saudi participants had a mean number of 8.92 ± 0.660 palatal rugae, whereas in Kuwaiti participants it was 8.68 ± 0.649 (p = 0.001). When rugae length was assessed between genders among Saudi participants, it was found that the majority of participants had primary rugae with a length of more than 5 mm, and the difference was statistically significant (p = 0.002). The majority of Saudi males had forwardly positioned rugae, while the majority of Saudi females had more backwardly placed rugae. When rugae length was assessed in males and females among Kuwaiti participants, it was found that males had more primary rugae than females. This study found that the majority of Kuwaiti males had a wavy shape of rugae, while the majority of Kuwaiti females had more straight rugae. Conclusions This study concluded that among the two ethnic groups, the total number, length, direction, unification, and shape of rugae were different between genders, with significant differences in some parameters. Therefore, palatal rugoscopy might be useful as a tool to recognize gender and ethnicity and may provide better results when used as an additional tool along with other dependable forensic tools.

Clinical comparative study on the accuracy of palatal rugae in models obtained by different impression materials and intraoral scanning.

OBJECTIVE: Palatal rugae are frequently used in the evaluation of tooth movement after treatment in orthodontics and as a stable region in superimposition. It is important to note that the impression method and material used to record the rugae region affect the accuracy of the impression. The aim of this study is to compare the accuracy of palatal rugae, in three-dimensional (3D) by employing both conventional and digital impression methods. MATERIALS AND METHODS: In this study, 22 patients (12 females, 10 males) mean age of 13.5 ± 1.7 years old were selected with complete permanent dentition. Three different impressions were taken from the maxillae of the patients: conventional impression using silicone rubber impression material, conventional impression using alginate impression material, and optical impression using an intraoral scanner. The impressions' digital data were analyzed by the GOM Inspect (Version 2018, Braunschweig, Germany), a 3D analysis software. The Root Mean Square (RMS) values of the total ruga region were evaluated in this software. The data were statistically analyzed using the Jamovi program. The Kruskal-Wallis test and Mann-Whitney U test were performed due to the non-normal distribution of the data. RESULTS: There is no statistically significant difference between the comparison points of the right and left rugae's medial and lateral points and total rugae regions' RMS values. Although there was no statistically significant difference, the total RMS values of alginate and digital scan measurements showed closer results than the RMS values of silicone and digital scan measurements. CONCLUSION: The study found that there was no statistically significant difference in the total RMS values of the ruga region between traditional and digital impression methods. CLINICAL RELEVANCE: The treatment period in orthodontics is long. Different impression materials and methods can be used for diagnostic, mid-treatment, and final impressions. For superimpositions and treatment and post-treatment palatal ruga evaluations, traditional and digital impression methods are clinically acceptable and can be used as alternatives to each other.

A morphometric approach to morphology analysis of palatal rugae in sibling groups.

Recent advances in imaging technologies, such as intra-oral surface scanning, have rapidly generated large datasets of high-resolution three-dimensional (3D) sample reconstructions. These datasets contain a wealth of phenotypic information that can provide an understanding of morphological variation and evolution. The geometric morphometric method (GMM) with landmarks and the development of sliding and surface semilandmark techniques has greatly enhanced the quantification of shape. This study aimed to determine whether there are significant differences in 3D palatal rugae shape between siblings. Digital casts representing 25 pairs of full siblings from each group, male-male (MM), female-female (FF), and female-male (FM), were digitized and transferred to a GM system. The palatal rugae were determined, quantified, and visualized using GMM computational tools with MorphoJ software (University of Manchester). Principal component analysis (PCA) and canonical variates analysis (CVA) were employed to analyze palatal rugae shape variability and distinguish between sibling groups based on shape. Additionally, regression analysis examined the potential impact of shape on palatal rugae. The study revealed that the palatal rugae shape covered the first nine of the PCA by 71.3%. In addition, the size of the palatal rugae has a negligible impact on its shape. Whilst palatal rugae are known for their individuality, it is noteworthy that three palatal rugae (right first, right second, and left third) can differentiate sibling groups, which may be attributed to genetics. Therefore, it is suggested that palatal rugae morphology can serve as forensic identification for siblings.

Palatal rugae as an unique and stable marker in personal identification-An interracial pilot study.

Background: In post-mortem scenarios, often it is a very difficult process to establish a person's identity. Rugae are unique in that they are protected from trauma as they are insulated from heat by tongue and buccal pad of fat unlike fingerprint or lip print that is prone to destruction. Aim and Objectives: This study was aimed to compare the palatal rugae among people of different races. The sole objectives of the study were to assess the predominant pattern in the selected groups, reliability of rugae pattern in personal identification, to evaluate reliability of sex determination and to compare the total number of rugae on right and left sides of the palate among the males and females. Study Design: A total of 90 subjects were enrolled into the study and divided into three groups that are African, Dravidian and Mongoloid population. Shapes of rugae present were analyzed according to the classification given by Kapali et al. (1997) and Thomas & Kotze (1983). Result: The predominant rugae shape in African and Dravidian population was wavy pattern, whereas Mongoloid race was predominant in curve pattern. African and Dravidian males were predominant in wavy pattern when compared to Mongoloid males where unification type was more predominant. Conclusion: A statistically significant association between the rugae shape in three populations exists, although subtle yet definite.

Are palatal rugae reliable markers for 3D superimposition and forensic human identification after palatal expansion? A systematic review.

OBJECTIVES: Palatal rugae are periodic structures situated in the palatal mucosa, often used as landmarks for human identification and superimposition of digital dental models. This review aims to collect the current evidence regarding whether orthodontic palatal expansion could affect the stability of the palatal rugae and to give preliminary guidelines. MATERIALS AND METHODS: A systematic review of the literature was performed in the scientific databases Pubmed; Embase; WoS; and Cochrane. Grey Literature was also sought (clinicaltrial.gov; ICTRP; AHRQ; INAHTA). The search protocol, was registered in PROSPERO (N*208722). Data extraction comprised: year of publication, journal, sample size, characteristics of the experimental and control group, type of expander, expansion protocol, rugae classification, measurement method on casts, time between casts, method error, rugae change, morphology change and overall outcome. Risk of bias of the included articles was evaluated with the Newcastle-Ottawa Scale. RESULTS: A total of 12394 manuscripts were retrieved after duplicate removal. From these, nine articles were finally included for data extraction. three studies scored as low risk of bias, two as medium and four as high. CONCLUSIONS: The morphology of the palatal rugae can be modified by palatal expansion techniques, especially by rapid maxillary expansion. The first rugae is the most stable along with the points close to the palatal midline, which should be used as a reference both for manual or semi-automatic superimpositions. Human identification and serial superimpositions based on palatal rugae should not be carried immediately post expansion and be taken in consideration with caution in patients who underwent prior palatal expansion.

Palatal Rugae as a Discriminating Factor in Determining Sex: A New Method Applicable in Forensic Odontology?

The purpose of this study is a new method that can help to identify the sex through the study of palatal rugae, comparing sagittal sections of the hard palate using Cartesian coordinates and evaluating the assistance given by digital technology and its applicability in this method. In this study, 57 digital impressions were examined and divided in two groups based on sex. Results: 2223 impression sections were studied and 145 coordinates that were present with a frequency greater than 50% in one or both groups were obtained: 52 discriminating traits (DT) in the male group, 29 discriminating traits in the female group, and 64 common traits (CT). The DTs in the female group showed no statistically significant difference from the same coordinates in the male one (p = 0.832). Statistically significant differences were observed in the DTs in the male group compared to the same coordinates in the female group (p = 0.018). No statistically significant differences were observed in the frequency of DTs in both sexes (p = 0.056). Further research in forensic odontology is needed to determine its scientific certainty. It is certain that digital technology may one day be a valuable support for the forensic odontologist but to date the lack of dedicated and certified programs limits its reliability.

An Association of Morphological Characteristics of Palatal Rugae and Dental Malocclusion in an Adult Indian Population: A Cross-Sectional Study.

Introduction The formation of palatal rugae is completed in the early intrauterine stage, and because of their unique and permanent pattern in each individual, they can be utilized in forensics to identify a person. Objective The primary objective of this study was to determine an association between the rugae pattern and the dental malocclusion system described by Angle. Materials and methods A prospective cross-sectional, observational study was conducted on pretreatment dental casts of 400 subjects in an age range of 18-40 years. The samples were divided according to Angle's system of classification of malocclusion into Class I, Class II, and Class III. The number, length, pattern, and orientation of the three anterior-most primary rugae on both sides of the palatal region were studied. Results Significant differences were noted in the mean number of palatal rugae and mean lengths of rugae 1 and 2 on the right side (p < 0.001) and rugae 3 on the left (p < 0.001) side among the different malocclusion groups. Curved and wavy patterns were predominant, and significant differences were found among the groups (p < 0.05), whereas non-significant differences were observed in the rugae orientation between the groups on the right and left sides. Conclusions The current study showed significant differences in the length, number, and pattern of the palatal rugae among Angle's classes of malocclusion. Clinical implications Palatal rugae can be effectively used to identify dental malocclusion at an early stage and can, therefore, help intercept the developing malocclusion.

Establishing the reliability of incisive papilla and palatal rugae patterns in individual identification.

Context: The study of palatal rugae forms an important basis of human identification, especially due to mass disasters where routinely used techniques may not be helpful. Aims: This study aimed at evaluating the palatal rugae and incisive papilla on the basis of shape. Settings and Design: The study was conducted in 280 individuals (males and females) among dental students of Dayananda Sagar College of Dental Sciences. Materials and Methods: The study included 280 students from Dayananda Sagar College and out-patients from the orthodontics department. Pictures of rugae and the incisive papilla were taken from individuals aged 10-36 using a camera, mirror, and lighting. Two investigators analysed the shape of the rugae and incisive papilla using classification systems by Thomas and Kotze, and Ortman and Tsao, respectively. Statistical Analysis Used: The data were statistically analysed using SPSS 20.0 software, and a significance level of P ≤ 0.05 was used. Results: The results suggested that rugae showing a wavy shape were the most common pattern in both the genders. Significant differences were observed in the curved rugae type between males and females. In incisive papillae evaluation, the pear shape was the most common, with the triangular shape being the least common. Conclusions: It can be concluded that evaluation of palatal rugae along with the incisive papilla can be an important tool for identification of an individual and for evaluating various ethnic populations.

Is Palatal Rugae Pattern a Reliable Tool for Personal Identification following Orthodontic Treatment? A Systematic Review and Meta-Analysis.

BACKGROUND: To qualitatively and quantitatively review the reliability of palatal rugae as a tool for personal identification following orthodontic treatment. METHODS: Cross-sectional retrospective studies assessing the accuracy of matching palatal rugae pattern pre- and post-orthodontic treatment were identified from PubMed and SCOPUS databases. The title and abstract of the articles identified in the search were screened for potential duplicates and relevancy to the topic of interest. The full text of the articles selected in the screening was analyzed using the inclusion and exclusion criteria. Quantitative analysis of the studies representing coherent data in terms of age and treatment choice was performed using RevMan software. RESULTS: Out of 64 screened articles, only 18 articles fulfilled the eligibility criteria and were included in the systematic review. Out of these 18 articles, only 3 studies had data compatible with the quantitative analysis. Significant changes were noted in lateral first rugae in transverse bilateral direction (p = 0.02) and between second and third lateral rugae of the left side in the anteroposterior direction (p = 0.04). Despite the dimensional changes, observers in most studies were able to accurately (>90%) match the palatal rugae pre- and post-orthodontic treatment through visual observation. CONCLUSION: The accuracy of the visual matching, despite the significant dimensional changes, indicates that morphology could have potentially been the major matching factor. Thus, a combination of dimensional and morphological evaluation of the palatal rugae could potentially increase the accuracy of personal identification.

Evaluation of the stability of the palatal rugae using the three-dimensional superimposition technique following orthodontic treatment.

OBJECTIVES: To determine the uniqueness and stability of the palatal rugae after orthodontic treatment. METHODS: Cast models of untreated subjects (n = 50) were obtained twice at intervals of 8-30 months. Cast models of patients who received non-extraction (n = 50) and extraction (n = 50) orthodontic treatment were obtained before and after treatment at intervals of 11-41 months and 14-49 months, respectively. All 300 cast models were scanned digitally. The palatal rugae were manually extracted and transformed into 3D point clouds using reverse engineering software. An iterative closest point (ICP) registration algorithm based on correntropy was applied, and the minimum point-to-point root mean square (RMS) distances were calculated to analyze the deviation of palatal rugae for scans of the same subject (intrasubject deviation [ISD]) and between different subjects (between-subject deviation [BSD]). Differences in ISD between each group and the deviation between ISD and BSD of all 150 subjects were evaluated. RESULTS: Significant differences were found in the 150 ISD and 1225 BSD in each group, as well as the 150 ISD and 11,175 BSD across all groups. The mean values of ISD in untreated, non-extraction and extraction group were 0.178, 0.229 and 0.333 mm, respectively. When the first ruga was excluded in the extraction group, the mean ISD decreased to 0.241 mm, which was not significantly different from that in the non-extraction group (p = 0.314). CONCLUSIONS: Orthodontic treatment can influence the palatal rugae, especially in cases of extraction. Furthermore, variation mainly existed in the first ruga in cases of extraction. However, palatal rugae are still unique and may be used as a supplementary tool for individual identification. CLINICAL SIGNIFICANCE: This study indicates that palatal rugae might be applied in the evaluation of orthodontic tooth movement and forensic individual identification. The registration algorithm based on correntropy provides a reliable, precise, and convenient method for palatal rugae superimposition.

Correlation between the anatomical morphology of palatal rugae and sex / Correlación entre la morfología anatómica de las rugas palatinas y el sexo

SUMMARY: To investigate the correlation between the anatomical morphology of palatal rugae and sex. The study sample consisted of 120 students studying from Shanxi Medical University, of which 60 were females and 60 were males. The digital model of the palatal rugae was obtained by the 3 Shape TRIOS intraoral scanner. And the shapes of palatal rugae were recorded. Association between palatal rugae shape and sex were tested using Chi-square analysis. And logistic regression analysis (LRA) was carried out to calculate the accuracy of gender prediction using rugae shapes. There was a statistically significant difference between males and females in terms of the distribution of wavy and circular palate rugae. The use of logistic regression analysis obtained a sex predictive value of 65 % when all the rugae shapes were analyzed. Digital images of the palatal rugae morphology contribute to more accurate and convenient for data collection and transformation. It was found that rugae patterns can moderately identify the sex of the specific population when multivariate statistics such as LRA is applied. The palatal rugae morphology can be utilized as an assistant measure for sex identification.

RESUMEN: Investigar la correlación entre la morfología anatómica de las rugas palatinas y el sexo. En la muestra de este estudio se incluyeron 120 estudiantes de la Universidad Médica de Shanxi, (60 mujeres y 60 hombres). El modelo digital de las rugas palatinas se obtuvo mediante escáner intraoral 3 Shape TRIOS, y se registraron las formas de las rugas palatinas. La asociación entre la forma de las rugas palatinas y el sexo se evaluó mediante un análisis de Chi-cuadrado; para calcular la precisión de la predicción de sexo se llevó a cabo un análisis de regresión logística (ARL) Se observó una diferencia estadísticamente significativa entre hombres y mujeres en términos de la distribución de las rugas palatinas onduladas y circulares. El uso de análisis de regresión logística obtuvo un valor predictivo de sexo del 65 % cuando se analizaron todas las formas de las rugas. Las imágenes digitales de la morfología de las rugas palatinas contribuyen a una recopilación de datos más precisa. En este análisis se determinó que los patrones de rugas pueden identificar relativamente el sexo de una población específica, cuando se aplican estadísticas multivariadas como ARL. La morfología de las rugas palatinas se puede utilizar como medida de ayuda para la identificación de sexo.

Marker-free registration for intraoperative navigation using the transverse palatal rugae.

BACKGROUND: Registration is most important in navigation-assisted-surgery including the matching between the coordinates of the actual patient space and the medical image. Marker-based techniques mostly include marker application with subsequent radiography. In the edentulous patient, maker-free methods are generally less accurate and reproducible. This new method of a marker-free registration uses the transverse palatal rugae as registration structures. METHODS: (1) Segmentation of bone and hard palatal mucosa from initial 3D imaging (DICOM), (2) Maxillary intraoral-scan with transfer to the 3D imaging using an Iterative-Closest-Point-Algorithm (ICP), (3) Marking digital registration points with holes within IOS-stl, (4) Transformation of the spatially aligned IOS-stl to LabelMap and storage in DICOM (IOS-DICOM), (5) Alignment of DICOM and IOS-DICOM, (6) Controlled positioning of digital reg. points and clinical correlation. RESULTS: Fiducial localization error (0.48 mm) and Target registration error (0.65 mm) is comparable to those of tooth-supported registration methods. CONCLUSION: This approach of marker-free registration for navigation-assisted-surgery could improve the treatment in edentulous patients avoiding additional imaging and invasive marker insertion.

The Posterior Extension of the Palatal Rugae as an Anatomical Constraint for Soft Tissue Grafts in a Saudi Arabian Population.

Background The purpose of this study was to investigate the distal extension of the palatal rugae area as an anatomical constraint on the harvesting of palatal soft tissue grafts in a Saudi Arabian population. Additionally, factors that could affect or predict the extension were considered. Methods Three hundred seventy-four (374) dental casts from Saudi nationals currently residing in Riyadh (170 males and 204 females) were included. Two independent observers used a standardized probe to measure the posterior extent of the rugae on each stone cast bilaterally on a horizontal base. A sharp graphite pencil was used to mark the measurements from the origin of the rugae to their terminal ends on the cast, and a magnification lens was used to identify them. Using this technique, the most posterior extension of the rugae was marked and then analyzed. The normal approximation test for binomial distribution was used to determine the proportion of the subjects with rugael extensions beyond the mesial end of the upper second premolar, and logistic regression was used to see the association of this extension with other factors. Results The asymptotic chi-squared (p = 0.0002) McNemar tests revealed that the posterior distal extension of the rugae was not the same on both sides. A normal approximation test for the left side with 95% confidence intervals (CIs) with the "rugael extension proximal to the mesial end of the upper second premolar" category considered "success" found that the proportion of upper second premolars with rugael extensions proximal to the mesial end was not significantly different to the proportion of rugael extensions beyond the mesial end of the upper second premolars (95% CI: 48.69%-58.79%, p = 0.147). Conversely, the proportion of the upper second premolars with rugael extensions proximal to the mesial end was significantly lower than that beyond the mesial end on the right (95% CI: 35.92%-45.89%, p = 0.00004). Gender, age, and palatal shape did not significantly affect the posterior extension of palatal rugae. Conclusions The palatal rugae on the left side of a sample of the Saudi Arabian population do not considerably extend beyond the upper second premolar mesial aspect, which may provide reliable soft tissue grafts for esthetic mucogingival surgery.

A Morphometric Analysis of Palatal Rugae Patterns in a Saudi Arabian Population.

Background Palatal rugae patterns are useful in the field of forensic dentistry. Ethnicity has a significant effect on the development and final morphological pattern of palatal rugae. This study focused on a morphological analysis of the palatal rugae in a Saudi population to determine if any differences based on age and gender could support identifying an individual. Materials and methods This cross-sectional study conducted at the College of Dentistry, King Saud bin Abdul Aziz University for Health Sciences, was undertaken to evaluate 496 dental casts from the participant database of Saudi nationals from Riyadh. The rugae were delineated using a sharp graphite pencil under adequate light and magnification. The rugae patterns were classified based on the length, shape, and direction of the rugae by two observers as per Thomas and Kotze's criteria. Results The asymptotic chi-square McNemar test indicated bilateral symmetry for all the characteristics of the palatal rugae, except for the backward and forward directions of the rugae. Two-way analysis of variance (ANOVA) revealed a statistically significant interaction between the effects of age group and gender on the primary rugae count (F(3, 488) = 7.466, p <0.05)). In addition, age had a statistically significant effect on the fragmentary rugae (p <0.05), and gender had a statistically significant effect on the circular and backward patterns of the rugae (p<0.05). The females had a higher incidence of backward-directed rugae and the males had more circular rugae. No other significant difference was evident, based on gender. The logistic regression analyses showed a significant association between the circular (OR=1.298; 95% CI= 1.061-1.588) and backward (OR= 0.898; 95% CI= 0.828-0.975) palatal rugae and gender. Also, there was a significant association of the fragmentary palatal rugae (PR) (OR=1.274; 95% CI= 1.084-1.498) with the age group younger than 16 years. Conclusion In a Saudi Arabian ethnic group, the varying type of length of the palatal rugae patterns can be used to identify the age group while the direction and shape can be used to determine gender, although with limited accuracy. Post-mortem identification may benefit from using them along with other reliable forensic tools. There is a need to conduct continued research on diverse populations and ethnic groups in order to evaluate the PR potential in forensic dentistry.

Expression of Sonic Hedgehog and pathway components in the embryonic mouse head: anatomical relationships between regulators of positive and negative feedback.

OBJECTIVE: The Hedgehog pathway is a fundamental signaling pathway in organogenesis. The expression patterns of the ligand Sonic Hedgehog (Shh) and key pathway components have been studied in many tissues but direct spatial comparisons across tissues with different cell compositions and structural organization are not common and could reveal tissue-specific differences in pathway dynamics. RESULTS: We directly compared the expression characteristics of Shh, and four genes with functional roles in signaling and whose expression levels serve as readouts of pathway activity in multiple tissues of the embryonic mouse head at embryonic day 15.5 by serial in situ hybridization. The four readout genes were the positive feedback regulator Gli1, and three negative feedback regulators, Patched1, Patched2, and Hedgehog Interacting Protein. While the relative abundance of Gli1 was similar across tissues, the relative expression levels and spatial distribution of Shh and the negative feedback regulators differed, suggesting that feedback regulation of hedgehog signaling is context dependent. This comparative analysis offers insight into how consistent pathway activity could be achieved in tissues with different morphologies and characteristics of ligand expression.