Query: abnormal geometric outlines of tooth

title: Tooth Outline Shape Analysis of the Ryukyu Wild Boar (Sus scrofa riukiuanus) and the Japanese Wild Boar (S. s. leucomystax) by Geometric Morphometrics
abstract: We examined whether the shapes of the teeth could be used to distinguish morphological differences of modern Sus scrofa between subspecies, and between regions. The occlusal outlines of the lower teeth of five populations of the Ryukyu wild boar (S. s. riukiuanus) and two populations of the Japanese wild boar (S. s. leucomystax) were photographed and digitized into landmarks. The landmark coordinates were statistically compared among the populations. As a result, correct assignment rates of the populations based on their tooth shape was the highest for the fourth deciduous premolar. Pairwise test detected significant differences in tooth outline shape between the two subspecies. In addition, the tooth outline shapes of geographically adjacent populations tended to be similar. The results in this study indicated that the evaluation of tooth outline shapes, especially that of the fourth deciduous premolar, is a powerful approach for distinguishing subspecies of S. scrofa as well as for evaluating geographic variation among them. This method is useful in archaeological and paleontological studies because of its applicability for isolated teeth, and has potential to increase our understanding about the history of macroevolution, migration, and introduction of S. scrofa in the Japanese archipelago.

title: Geometric morphometric analysis of shape outlines of the normal and abnormal fetal skull using three dimensional sonographic multiplanar display
abstract: Geometric morphometric analysis has been used to quantify differences in biological shapes. Cranial irregularities are described in anomalous fetuses but are qualitative and ill defined. Our goal was to apply geometric morphometric statistical analysis using three dimensional (3D) multiplanar display to quantify shape differences in normal and abnormal fetal skulls.

title: The utility of captive animals in actualistic research: A geometric morphometric exploration of the tooth row of Alligator mississippiensis suggesting ecophenotypic influences and functional constraints
abstract: Captive broad snouted crocodylians are generally thought to have wider, shorter rostra than their wild counterparts. Interpreted to reflect morphological change in response to the conditions of captivity, this qualitative pattern could affect the utility of these animals in a variety of fields of research. However, due to relative ease of access and availability of life history data, captive animals are often utilized in actualistic research. Thus, this issue should be addressed in more detail. Here we explore snout shape variation between captive and wild members of Alligator mississippiensis using two dimensional (2D) morphometric techniques. Several landmark schemesare used to assess the utility of different aspects of morphology in distinguishing the groups. While statistical analyses consistently differentiated between the groups, the area of morphospace occupied by wild members of A. mississippiensis generally overlapped with the larger area encompassing the captive specimens. This indicates that the captive condition is not as uniform as previously thought and instead encompasses a large spectrum of morphologies, ranging from the stereotypical broad, shortened snouts to outlines that are indistinguishable from the wild morphotype. These results align well with the interpretation that this change reflects an extreme example of ecophenotypy, since ranched, farmed, or zoo organisms are held in an array of enclosures, ranging from indoor, climate controlled pens to outdoor, more natural areas. This variation in environments should be reflected in different reactions to the animals' surroundings, resulting in a broad spectrum of morphotypes. While wild specimens are still preferred, especially for fine scale analyses, these results indicate that not all captive members of A. mississippiensis exhibit the extreme morphological alterations often cited in the literature. Weighing the conditions in which the animals are held and exploring the possibility of morphological differences against the benefits of using captive specimens should be part of any actualistic study.  2016.

title: Use of 3D finite element models in study of normal and abnormal dental mobility as affected by a minimal decrease in alveolar bone height
abstract: The study deals with dental mobility and dental root side periodontal pressure for leftside mandibular teeth. Geometric models of the teeth were generated from patient V.'s computed tomographic data. Displacements and stresses in the tooth/periodontium system were determined using ANSYS integrated three dimensional finite elements method. Vertical and horizontal biting effects in case of normal and periodontitis reduced alveolar bone height were reviewed. An almost two fold increase in dental mobility as compared to normal level was showed to cause contact stresses at the dental root to periodontium interface to be built up by only about 10% to 20% thus indicating absence of periodontal overload. The paper shows an increase in periodontal load should be estimated from maximum displacements of periodontium contacting part rather than the entire tooth. These displacements were increased by 20% to 40% thus correlating with only small contact stress buildup.

title: Organic molecules with abnormal geometric parameters
abstract: Organic molecules, the structural parameters of which (carbon carbon bond lengths, bond and torsion angles) differ appreciably from the typical most frequently encountered values, are discussed. Using many examples of 'record breaking' molecules, the limits of structural distortions in carbon compounds and their unusual chemical properties are demonstrated. Particular attention is devoted to strained compounds not yet synthesised whose properties have been predicted using quantum chemical calculations. Factors that ensure the stability of such compounds are outlined. The bibliography includes 358 references.

title: Exploring the effects of acid mine drainage on diatom teratology using geometric morphometry
abstract: Metal pollution of aquatic habitats is a major and persistent environmental problem. Acid mine drainage (AMD) affects lotic systems in numerous and interactive ways. In the present work, a mining area (Rosia Montana) was chosen as study site, and we focused on two aims: (i) to find the set of environmental predictors leading to the appearance of the abnormal diatom individuals in the study area and (ii) to assess the relationship between the degree of valve outline deformation and AMD derived pollution. In this context, morphological differences between populations of Achnanthidium minutissimum and A. macrocephalum, including normal and abnormal individuals, were evidenced by means of valve shape analysis. Geometric morphometry managed to capture and discriminate normal and abnormal individuals. Multivariate analyses (NMDS, PLS) separated the four populations of the two species mentioned and revealed the main physico chemical parameters that influenced valve deformation in this context, namely conductivity, Zn, and Cu. ANOSIM test evidenced the presence of statistically significant differences between normal and abnormal individuals within both chosen Achnanthidium taxa. In order to determine the relative contribution of each of the measured physico chemical parameters in the observed valve outline deformations, a PLS was conducted, confirming the results of the NMDS. The presence of deformed individuals in the study area can be attributed to the fact that the diatom communities were strongly affected by AMD released from old mining works and waste rock deposits.

title: Regenerative Endodontic Procedure (REP) in single session with MTAD disinfection on immature avulsion tooth: 4 year control
abstract: Regenerative endodontic procedures (REP) on teeth with necrotic pulps and open apices require robust disinfection. The purpose of this case report is to present clinical and radiographic findings of a regenerative endodontic procedure that utilizes MTAD for single visit disinfection of a tooth with necrotic pulp and open apex with 4 year follow up. A maxillary central incisor of a 7 year old girl was avulsed and replanted. The tooth developed pulpal necrosis and symptomatic apical periodontitis. After access preparation into the empty chamber, the canal was irrigated with 5.25% NaOCl followed by BioPure MTAD (Dentsply, Tulsa Dental Specialties, Tulsa, OK) Intracanal bleeding was stimulated. 3 mm of Mineral Trioxide Aggregate (MTA) was placed directly over the clot and access was permanently restored with composite. Clinical examination at 1 year and 6 months showed a closed apex with no sensitivity to percussion or palpation. After 4 years, the tooth was asymptomatic and responsive to both cold and electric pulp testing. Potential differences in angulation between preoperative and recall images were corrected with a geometrical imaging program, NIH ImageJ with TurboReg plug in. The present case demonstrates REP of a tooth with necrotic pulp and open apex in a single visit with MTAD disinfection.  Rita Hung, Department of Endodontics, School of Dentistry, Loma Linda University, USA, E mail: drhungendo@gmail.com Received: January 12, 2019;  January 21, 2019;   Pulpal status and degree of root development are major factors in treatment planning for teeth requiring vital pulp treatment or root canal treatment [1] Vital pulp treatment can be performed on teeth with open and closed apices. Permanent teeth with closed apices are routinely endodontically treated with a high rate of long term success  However, teeth with immature and often divergent apices are not suitable for routine endodontic techniques due to large diameter apical foramens and thin dentinal walls susceptible to root fracture  Onevisit or two visit mineral trioxide aggregate (MTA) apexification is currently used in teeth with necrotic pulps and open apices  with a high success rate [4] However, this procedure addresses only technical issues involved in treatment of these teeth and does not completely eliminate the chance for root fracture  There is a growing body of evidence suggesting the possibility of bringing vital tissues into the pulp space of teeth with necrotic pulps and open apices, along with continued growth of the root and thickening of the root canals walls [6] Hargreaves et al.  identified three components necessary for the success of this procedure: stem cells, signaling molecules and a three dimensional physical scaffold that can support cell growth and differentiation. Regenerative endodontic procedures are only possible when the root canal space is completely disinfected, and a microenvironment is created that is conducive to repopulation by vital tissues [7 9] Many published regenerative endodontic cases describe a range of clinical protocols with varying irrigants, medicaments, clinical procedures, and follow up times with little standardization  Frank et al.  demonstrated the formation of an apical closure with repeated calcium hydroxide [Ca(OH)2] dressings. It was theorized that this continued root development is a result of the stimulation of residual papilla and root sheath cells that survived apical infection  Hoshino and colleagues [13,14] have demonstrated the effectiveness of triple antibiotic paste (TAP) a mixture of ciprofloxacin, metronidazole, and minocycline, in eradicating bacteria from the infected dentin of root canals. Thereafter, Banchs and Trope  presented a successful case of revascularization of an immature mandibular second premolar following disinfection with sodium hypochlorite (NaOCl) CHX and TAP. While TAP has become a valuable intracanal medicament for eradication of bacteria in regeneration procedures [16] other disadvantages such as staining, stem cell viability and multiple treatment visits warrant investigation into other disinfection techniques. BioPure MTAD (MTAD) (Dentsply, Tulsa Dental Specialties, Tulsa, OK) is a mixture of tetracycline isomer, citric acid and detergent that is bacteriostatic and shows substantivity as it can be absorbed and gradually released from tooth structure such as cementum and dentin  While reports on MTAD have proven efficacy as a final irrigation with antibacterial properties, a search of literature reveals a lack of report on the use of MTAD in regeneration procedures. The purpose of this case report is to present clinical and radiographic findings of a single visit regenerative endodontic procedure that utilizes MTAD for disinfection of an avulsed necrotic immature tooth with a 4 year follow up. Hung R (2019) Regenerative Endodontic Procedure (REP) in single session with MTAD disinfection on immature avulsion tooth: 4 year control Volume 2: 2 4 J Dent Res Rep, 2019 doi: 10.15761/JDRR.1000109 Case report A 7 year old girl was seen in a private endodontic practice for evaluation and treatment of the maxillary right central incisor #8) The patient's mother reported that the tooth had been avulsed three days prior to the visit to the endodontic office. The patient's orthodontist irrigated the tooth with chlorhexidine (CHX) and replanted the tooth with a total extra oral dry time of 60 minutes. He stabilized the tooth with stainless steel wire and brackets and referred the patient for endodontic evaluation. The medical history of the patient was noncontributory. Extra oral examination revealed no abnormalities or asymmetries. Clinical examination revealed presence of orthodontic stabilization and no discoloration or fracture of tooth #8. The tooth was tender to percussion and palpation and had no response to cold or electric pulp testing (EPT) Adjacent teeth responded normally to vitality tests. Radiographic examination revealed presence of widened periodontal ligament space (Figure 1A) A follow up examination was performed three weeks later without any change to vitality testing. On the basis of clinical and radiographic findings, a pulpal diagnosis of necrotic pulp and a periapical diagnosis of symptomatic apical periodontitis were made. A written informed consent for the procedure of regeneration with the use of MTAD was obtained from the patient's mother. Local anesthesia was administered with lidocaine 2% 1:100,000 epinephrine and articaine 4% 1:100,000 epinephrine. After placement of rubber dam, an access cavity was prepared. Upon entry into the root canal, an empty chamber with no vital tissue or blood was noted. Working length was determined by placing a large file in the canal and confirming with a radiograph. The canal walls were lightly instrumented with large files and the canal was irrigated with approximately 10 mL of 5.25% NaOCl and dried with paper points. One mL of MTAD was placed in the canal and left for 5 minutes. The canal was then rinsed with 4 mL of MTAD and dried with paper points. A pre bent ISO #25 K file was extended 2 millimeters beyond the working length to stimulate bleeding to 3 millimeters below the cementoenamel junction (CEJ) Three to four millimeters of gray Mineral Trioxide Aggregate (MTA) (Dentsply, Tulsa Dental Specialties, Tulsa, OK) was gently condensed over the blood clot  The tooth was then restored with a bonded composite restoration. The patient returned to the endodontic office after 6 months for reevaluation. Based on radiographic examination, the root apex appeared to be closing and patient reported no pain or symptoms. After 1 year and 6 months, the apex was closed, and the patient continued to be asymptomatic (Figure 2A) At 2 year follow up, tooth discoloration was noted, and walking bleach treatment was performed with sodium perborate/saline paste. After one week, shade of #8 matched patient's adjacent dentition and access was restored with a bonded composite restoration. After 2 years and 6 months, tooth #8 continued to be asymptomatic with no sensitivity to percussion or palpation tests. Vitality tests at this time revealed a positive response to both cold and EPT. After 4 years, tooth #8 continued to respond positive to cold and EPT with no sensitivity to percussion or palpation (Figure 2B) and no crown discoloration (Figure 2C) Positioning and angulation were mathematically corrected using the ImageJ Software (ver 1.51; National Institutes of Health, Bethesda, MD) and the plug in application TurboReg (Biomedical Imaging Group, Swiss Federal Institute of Technology, Lausanne, VD, Switzerland) in the method described by Bose et al.  The root length and remaining dentin thickness were measured and compared from the post operative radiograph and 4 year recall radiograph. While root length resulted in no apparent change, the remaining dentin thickness increased by 175%  The present case report demonstrates a successful treatment option for an avulsed permanent tooth with necrotic pulp and an immature apex. It highlights the importance of case selection, complete disinfection and proper treatment to achieve continued apical development and REP of a tooth with previously necrotic pulp. Similar to many cases presented in the literature, advantages that contributed to the success of this regenerative endodontic procedure were the young age of the patient and the immature stage of tooth development with open apex, thin walls and short root. Estefan et al.  reported that younger age groups and wider preoperative apical diameters were better candidates for revascularization procedures resulting in greater increases in root thickness, root length and apical narrowing. A) Preoperative periapical radiograph showing tooth #8 with an open apex and periapical radiolucency.

title: Lineage Specific Responses of Tooth Shape in Murine Rodents (Murinae, Rodentia) to Late Miocene Dietary Change in the Siwaliks of Pakistan
abstract: Past ecological responses of mammals to climate change are recognized in the fossil record by adaptive significance of morphological variations. To understand the role of dietary behavior on functional adaptations of dental morphology in rodent evolution, we examine evolutionary change of tooth shape in late Miocene Siwalik murine rodents, which experienced a dietary shift toward C4 diets during late Miocene ecological change indicated by carbon isotopic evidence. Geometric morphometric analysis in the outline of upper first molars captures dichotomous lineages of Siwalik murines, in agreement with phylogenetic hypotheses of previous studies (two distinct clades: the Karnimata and Progonomys clades) and indicates lineage specific functional responses to mechanical properties of their diets. Tooth shapes of the two clades are similar at their sympatric origin but deviate from each other with decreasing overlap through time. Shape change in the Karnimata clade is associated with greater efficiency of propalinal chewing for tough diets than in the Progonomys clade. Larger body mass in Karnimata may be related to exploitation of lower quality food items, such as grasses, than in smaller bodied Progonomys. The functional and ecophysiological aspects of Karnimata exploiting C4 grasses are concordant with their isotopic dietary preference relative to Progonomys. Lineage specific selection was differentially greater in Karnimata, and a faster rate of shape change toward derived Karnimata facilitated inclusion of C4 grasses in the diet. Sympatric speciation in these clades is most plausibly explained by interspecific competition on resource utilization between the two, based on comparisons of our results with the carbon isotope data. Interspecific competition with Karnimata may have suppressed morphological innovation of the Progonomys clade. Pairwise analyses of morphological and carbon isotope data can uncover ecological causes of sympatric speciation and define functional adaptations of teeth to resources.

title: A model for the molecular underpinnings of tooth defects in Axenfeld Rieger syndrome.
abstract: Patients with Axenfeld Rieger Syndrome (ARS) present various dental abnormalities, including hypodontia, and enamel hypoplasia. ARS is genetically associated with mutations in the PITX2 gene, which encodes one of the earliest transcription factors to initiate tooth development. Thus, Pitx2 has long been considered as an upstream regulator of the transcriptional hierarchy in early tooth development. However, because Pitx2 is also a major regulator of later stages of tooth development, especially during amelogenesis, it is unclear how mutant forms cause ARS dental anomalies. In this report, we outline the transcriptional mechanism that is defective in ARS. We demonstrate that during normal tooth development Pitx2 activates Amelogenin (Amel) expression, whose product is required for enamel formation, and that this regulation is perturbed by missense PITX2 mutations found in ARS patients. We further show that Pitx2 mediated Amel activation is controlled by chromatin associated factor Hmgn2, and that Hmgn2 prevents Pitx2 from efficiently binding to and activating the Amel promoter. Consistent with a physiological significance to this interaction, we show that K14 Hmgn2 transgenic mice display a severe loss of Amel expression on the labial side of the lower incisors, as well as enamel hypoplasia consistent with the human ARS phenotype. Collectively, these findings define transcriptional mechanisms involved in normal tooth development and shed light on the molecular underpinnings of the enamel defect observed in ARS patients who carry PITX2 mutations. Moreover, our findings validate the etiology of the enamel defect in a novel mouse model of ARS.

title: Geometric morphometrics reveal altered corpus callosum shape in pyridoxine dependent epilepsy
abstract: To evaluate the features and maturational changes in overall callosal shape in patients with pyridoxine dependent epilepsy (PDE) Methods Measurements were conducted through landmark based geometric morphometrics applied on cerebral MRIs of patients with PDE and age matched control subjects. The outline of the corpus callosum was manually traced in the midsagittal plane. Three hundred semi landmarks along the outline were collected and underwent statistical generalized Procrustes analysis. An allometric regression was applied to evaluate the callosal shape due to growth over time.  Thirty eight patients with PDE and 38 age and sex matched control subjects were included. Mean age at the time of the MRI in the patient group was 9.3 years (median 6.3 years, range 0.01 48 years) Significant differences (p 0.01) in the mean callosal shape between patients and controls were found. The allometric regression model revealed significant shape variations (p 0.01) between the 2 study groups across the developmental course after controlling for the effect of callosal size on shape. This latter effect turned out to be significant as well (p 0.001)  Patients with PDE show an altered callosal shape and variations in callosal ontogeny, which are likely secondary to the underlying genetic defect with abnormal function of antiquitin, the product of the ALDH7A1 gene.