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Journal of Veterinary Dentistry Sep 2023Pigs are diphyodonts with heterodont dentition and have been used in studies involving teeth and jawbone regeneration, and dental implants. Patterns of tooth eruption...
Pigs are diphyodonts with heterodont dentition and have been used in studies involving teeth and jawbone regeneration, and dental implants. Patterns of tooth eruption are used to age animals and determine the effects of environmental and genetic influences on occurrence of variations. As with other species, variations exist in the tooth eruption pattern in pigs. The aim of this study was to determine the permanent teeth eruption patterns of Nigerian local pigs. Twenty-six healthy pigs were observed throughout the study period. Pigs were firmly held in dorsal or lateral recumbency and their mouths gently held open to visually examine all quadrants of the dental arches (right and left maxillary, right and left mandibular). Observations were recorded from 16 weeks of age, until the last permanent tooth erupted. Results obtained from the study showed that males had lower mean values for eruption time (54%) of examined teeth in comparison to females. The mean values of eruption time for the maxillary third incisor, the mandibular and maxillary canines, and the mandibular fourth premolar teeth were statistically significant in the males (= .0017, = .0088, = .0002 and = .0244, respectively). Sixty-nine percent of the adult pigs did not have eruption of the mandibular first premolar, while polydontia was observed in the maxillary and mandibular incisors. These results show that intra-breed and inter-breed variations exist in the dental eruption pattern in pigs. The data obtained from this study can be used for comparative dental studies and can aid further research on the developmental anatomy of Nigerian local pigs.
Topics: Male; Female; Animals; Swine; Tooth Eruption; Dentition, Permanent; Incisor; Tooth, Supernumerary; Bicuspid; Swine Diseases
PubMed: 36721364
DOI: 10.1177/08987564231152390 -
The Angle Orthodontist Jul 2023To compare mandibular relative anchorage loss (RAL) under reciprocal anchorage between first and second premolar extraction cases in bimaxillary protrusion mild crowding...
OBJECTIVES
To compare mandibular relative anchorage loss (RAL) under reciprocal anchorage between first and second premolar extraction cases in bimaxillary protrusion mild crowding cases treated using clear aligner therapy (CAT).
MATERIALS AND METHODS
Adult patients who met the following criteria were included: treated using CAT with bilateral mandibular premolar extractions and space closure using intra-arch reciprocal anchorage. RAL was defined as the percent molar mesial movement relative to the sum of molar mesial plus canine distal movement. Movements of the mandibular central incisor (L1), canine (L3), and first molar (L6) were measured based on superimposition of the pre- and post-treatment dentition and jaw models.
RESULTS
Among the 60 mandibular extraction quadrants, 38 had lower first premolar (L4) and 22 had lower second premolar (L5) extracted. L6 mesial movement was 2.01 ± 1.11 mm with RAL of 25% in the L4 extraction group vs 3.25 ± 1.19 mm with RAL of 40% in the L5 extraction group (P < .001). Tooth movement efficacy was 43% for L1 occlusogingival movement, 75% for L1 buccolingual inclination, 60% for L3 occlusogingival movement, and 53% for L3 mesiodistal angulation. L1 had unwanted extrusion and lingual crown torquing whereas L3 had unwanted extrusion and distal crown tipping, on which the power ridges or attachments had little preventive effect.
CONCLUSIONS
The average mandibular reciprocal RAL is 25% or 40% for extraction of L4 or L5, respectively, in CAT cases. A RAL-based treatment planning workflow is proposed for CAT extraction cases.
Topics: Humans; Bicuspid; Tooth Movement Techniques; Molar; Malocclusion; Orthodontic Appliances, Removable
PubMed: 37343197
DOI: 10.2319/102222-727.1 -
American Journal of Biological... May 2024A modern pattern (rate and duration) of dental development occurs relatively recently during human evolution. Given the temporal overlap of Homo naledi with the first...
OBJECTIVES
A modern pattern (rate and duration) of dental development occurs relatively recently during human evolution. Given the temporal overlap of Homo naledi with the first appearance of fossil Homo sapiens in Africa, this small-bodied and small-brained hominin presents an opportunity to elucidate the evolution of enamel growth in the hominin clade. Here we conduct the first histological study of two permanent mandibular canines and one permanent maxillary first molar, representing three individuals attributed to H. naledi. We reconstruct the rate and duration of enamel growth and compare these findings to those reported for other fossil hominins and recent humans.
MATERIALS AND METHODS
Thin sections of each tooth were produced using standard histological methods. Daily and longer period incremental markings were measured to reconstruct enamel secretion and extension rates, Retzius periodicity, canine crown and molar cusp formation time.
RESULTS
Daily enamel secretion rates overlapped with those from recent hominins. Canine crown formation time is similar to that observed in recent Europeans but is longer than canine formation times reported for most other hominins including Australopithecus and H. neanderthalensis. The extended period of canine formation appears to be due to a relatively tall enamel crown and a sustained slow rate of enamel extension in the cervical portion of the crown. A Retzius periodicity of 11 days for the canines, and nine days for the molar, in H. naledi parallel results found in recent humans. An 11-day periodicity has not been reported for Late Pleistocene Homo (H. erectus, H. neanderthalensis) and is rarely found in Australopithecus and Paranthropus species.
DISCUSSION
Enamel growth of H. naledi is most similar to recent humans though comparative data are limited for most fossil hominin species. The high Retzius periodicity values do not follow expectations for a small-brained hominin.
Topics: Animals; Humans; Hominidae; Molar; Tooth Crown; Cuspid; Dental Enamel
PubMed: 38180115
DOI: 10.1002/ajpa.24893 -
The International Journal of Esthetic... Oct 2023To describe a digital workflow utilizing 3D printing technology to guide esthetic crown lengthening and control tooth preparation.
AIM
To describe a digital workflow utilizing 3D printing technology to guide esthetic crown lengthening and control tooth preparation.
CLINICAL CONSIDERATIONS
After the initial intraoral and face scans, an esthetic treatment plan was performed digitally based on the patient's personality and face type using artificial intelligence-based 3D smile design software. A 3D-printed tray relined with silicone over a 3D-printed model was used for the mock-up. A 3D-printed guide was implemented to assist esthetic crown lengthening by incorporating, simultaneously, information about the desired free gingival line and the alveolar bone level. Based on the initial planning, a set of reduction guides was 3D printed to check and correct the tooth preparation. Prior to the start of construction of the final monolithic restorations, their design was verified using 3D-printed prototypes. A stabilization splint was digitally designed and 3D printed to protect and maintain the final result.
CONCLUSIONS
Technologic advances can improve the predictability of an interdisciplinary esthetic approach. Digital planning can be transferred to clinical reality using a digital workflow, utilizing a set of appropriate 3D-printed guides, which can help to control clinical procedures based on the initial planning.
CLINICAL SIGNIFICANCE
By following the proposed step-by-step workflow, clinicians can achieve predictable results through an interdisciplinary approach, guiding both the periodontal plastic surgery and the restorative treatment after an individualized CAD/CAD procedure for 3D-printed guides.
Topics: Humans; Crown Lengthening; Artificial Intelligence; Esthetics, Dental; Tooth; Tooth Crown; Computer-Aided Design
PubMed: 37819562
DOI: No ID Found -
International Journal of Paleopathology Sep 2023Molar incisor hypomineralisation (MIH) is a developmental defect of enamel affecting the first permanent molars and often the incisors and affecting approximately 13% of... (Review)
Review
OBJECTIVE
Molar incisor hypomineralisation (MIH) is a developmental defect of enamel affecting the first permanent molars and often the incisors and affecting approximately 13% of the current population worldwide. Here, we aim to highlight potential differential diagnoses of MIH in archaeological collections (taphonomic discoloration, amelogenesis imperfecta, fluorosis, rachitic teeth, etc.).
METHODS
Causative factors of dental discolourations are identified through a literature review.
RESULTS
In an archaeological context, the sediments contained in the burial soil can lead to tooth discoloration. Taphonomic staining of the dentition may have a similar appearance to enamel hypomineralisation, and thus is a confounding factor that has the potential to cause miscalculation of the true prevalence of MIH within archaeological collections. Some rare medieval cases are reported in the modern literature but without microanalysis, misdiagnosis is possible. The aetiological factors of MIH are unknown but probably follow the multifactorial model involving systemic medical and genetic factors.
CONCLUSIONS
Systematic detection and diagnosis of MIH during anthropological studies is therefore of great interest.
SIGNIFICANCE
The hypotheses that only contemporary agents are causative factors of MIH could be refuted by the discovery of individuals living before medication or pollutants. The identification of MIH in a group of individuals also provides information regarding the health status of a population and reflects stress occurring during the period of mineralisation of the first permanent molars after secretion of the enamel matrix.
LIMITATIONS
Taphonomic alterations of archaeological remains prevent MIH diagnosis.
SUGGESTIONS FOR FUTURE RESEARCH
MIH diagnosis can be difficult in archaeological series and further non-destructive methods (microtomography, elemental analyses, etc.) are required.
Topics: Humans; Molar Hypomineralization; Molar; Incisor; Tooth Demineralization; Prevalence
PubMed: 37523814
DOI: 10.1016/j.ijpp.2023.07.004 -
American Journal of Orthodontics and... Aug 2023This study aimed to determine the effectiveness of different aligner anchorage preparations on mandibular first molars during premolar-extraction space closure with...
INTRODUCTION
This study aimed to determine the effectiveness of different aligner anchorage preparations on mandibular first molars during premolar-extraction space closure with clear aligners and to assess the effects of different modes of Class II elastics on mandibular first molars.
METHODS
Finite element models were constructed on the basis of cone-beam computed tomography data from an orthodontic patient. The models comprised maxilla, mandible, maxillary and mandibular teeth without first premolars, periodontal ligaments, attachments and aligners. Tooth displacement tendencies were calculated using different aligner anchorage preparations and Class II elastics on the models from the same patient. Three group sets were designed on the basis of the positions of aligner cutouts and buttons (mesiobuccal, distobuccal and lingual). Four groups were established in each of the 3 group sets. Four groups were created: (1) no elastic traction + no anchorage preparation, (2) anchorage preparation only, (3) elastic traction only, and (4) elastic traction + anchorage preparation. Different aligner anchorage preparations (0°, 1°, 2°, 3°) were applied on mandibular second premolars and molars. The Class II traction force was set to 100 g.
RESULTS
With clear aligners, mandibular first molars were subject to mesial tipping, lingual tipping and intrusion. In the condition of no elastic traction, aligner anchorage preparation resulted in distal tipping, buccal tipping, and extrusion effect on mandibular first molars. Aligner anchorage preparation was more effective in the distal and lingual cutout groups than in the mesial cutout group. In the condition of Class II elastic traction, the bodily movement of mandibular first molars was achieved with a 3° anchorage preparation for the mesial cutout group and a 1.7° anchorage preparation for distal and lingual cutout groups. Absolute maximal anchorage was achieved with a 2° anchorage preparation for distal and lingual cutout groups.
CONCLUSIONS
Clear aligner therapy caused mesial tipping, lingual tipping and intrusion of mandibular first molars during premolar-extraction space closure. Aligner anchorage preparation effectively prevented mesial and lingual tipping of mandibular molars. Distal and lingual cutout modes were more effective than mesial cutout modes in aligner anchorage preparation. For each aligner stage (0.25 mm), 1.7° aligner anchorage preparation and Class II elastics with distal or lingual cutouts led to the bodily movement of mandibular first molars, whereas 2° anchorage preparation reached absolute maximal anchorage.
Topics: Humans; Bicuspid; Finite Element Analysis; Tooth Movement Techniques; Molar; Maxilla; Orthodontic Appliances, Removable
PubMed: 37024337
DOI: 10.1016/j.ajodo.2022.12.013 -
Archives of Oral Biology Jun 2024This study aimed to carry out a systematic review of observational studies searching the association between salivary factors (amount and quality of saliva) and... (Review)
Review
OBJECTIVE
This study aimed to carry out a systematic review of observational studies searching the association between salivary factors (amount and quality of saliva) and noncarious cervical lesions (NCCL) in individuals with permanent dentition.
DESIGN
Cross-sectional, case-control, and cohort studies performed in humans with permanent dentition (population) and considering noncarious cervical lesions (outcome) in association with salivary characteristics (exposure) were included. PubMed, Web of Science, Cochrane, LILACS/BBO, Scopus, Embase, IBCT, NICE, OpenGrey, and Google Scholar were searched, with no language or date restrictions. Of 6561 potentially eligible studies, 142 were selected for full-text analysis. Three reviewers independently selected the studies, performed data extraction, and quality analysis through the Newcastle-Ottawa Scale.
RESULTS
Finally, ten references were included in the review, four case-control and six cross-sectional studies. Several salivary parameters were evaluated. Some parameters were considered associated with the presence of noncarious cervical lesions: salivary buffering capacity, salivary pH, citric acid, and calcium and potassium levels. The methodological quality varied across studies, with high heterogeneity among them.
CONCLUSIONS
Some associations between saliva and NCCL suggesting protective factors and others risk factors were found. However, the evidence is sparse and comes from a few studies with great heterogeneity. New scientific evidence, with standardized methods, should be encouraged. Understanding salivary parameters that influence the occurrence of NCCL is important to guide dentists in relation to etiological factors that could potentially be neglected. The results may help in the development of new and early diagnostic methods and treatments for noncarious cervical lesions.
Topics: Humans; Cross-Sectional Studies; Tooth Cervix; Dentition, Permanent; Observational Studies as Topic
PubMed: 38460485
DOI: 10.1016/j.archoralbio.2024.105945 -
Archives of Oral Biology Sep 2023Variation in enamel and dentine mineral concentration and total effective density can be reliably collected using Micro-CT scans. Both variables are suggested to reflect...
OBJECTIVE
Variation in enamel and dentine mineral concentration and total effective density can be reliably collected using Micro-CT scans. Both variables are suggested to reflect mechanical properties such as hardness and elastic modulus in dental tissues, meaning Micro-CT methods allow relative composition and mechanical properties to be collected non-destructively.
DESIGN
16 lower molars from 16 Catarrhine primates were Micro-CT scanned alongside hydroxyapatite phantoms using standardized settings and methods to calculate mineral concentration and total effective density. Mineral concentration, total effective density and thickness of dentine and enamel were calculated for four cusps, representing each 'corner' of the tooth and four lateral crown positions (i.e., mesial, buccal, lingual and distal).
RESULTS
The results show mean mineral concentration and total effective density values were higher in areas of thicker enamel, while the opposite was observed for dentine. Buccal positions had significantly higher mineral concentration and total effective density values than lingual areas. Cuspal positions had higher mean values than lateral enamel, for both dentine (mineral concentration cuspal: 1.26 g/cm; lateral: 1.20 g/cm) and enamel (mineral concentration cuspal: 2.31 g/cm; lateral: 2.25 g/cm). Mesial enamel had significantly lower values than other locations.
CONCLUSIONS
These common patterns across Catarrhine taxa may be linked to functional adaptations related to optimization of mastication and tooth protection. Variation in mineral concentration and total effective density may also be associated with wear and fracture patterns, and can be used as baseline information to investigate the effect of diet, pathological changes and aging on teeth through time.
Topics: Animals; Dentin; Dental Enamel; Molar; Tooth; Primates
PubMed: 37385050
DOI: 10.1016/j.archoralbio.2023.105752 -
PloS One 2024Tooth morphology is among the most well-studied indicators of ecology. For decades, researchers have examined the gross morphology and wear patterns of teeth as... (Review)
Review Meta-Analysis
Tooth morphology is among the most well-studied indicators of ecology. For decades, researchers have examined the gross morphology and wear patterns of teeth as indicators of diet, and recent advances in scanning and computer analysis have allowed the development of new and more quantitative measures of tooth morphology. One of the most popular of these new methods is orientation patch count (OPC). OPC, a measure of surface complexity, was originally developed to distinguish the more complex tooth crowns of herbivores from the less complex tooth crowns of faunivores. OPC and a similar method derived from it, orientation patch count rotated (OPCR), have become commonplace in analyses of both modern and fossil amniote dietary ecology. The widespread use of these techniques makes it possible to now re-assess the utility of OPC and OPCR. Here, we undertake a comprehensive review of OPC(R) and diet and perform a meta-analysis to determine the overall difference in complexity between herbivores and faunivores. We find that the relationship between faunivore and herbivore OPC or OPCR values differs substantially across studies, and although some support the initial assessment of greater complexity in herbivores, others do not. Our meta-analysis does not support an overall pattern of greater complexity in herbivores than faunivores across terrestrial amniotes. It appears that the relationship of OPC or OPCR to diet is taxon-specific and dependent on the type of faunivory of the group in question, with insectivores often having values similar to herbivores. We suggest extreme caution in comparing OPC and OPCR values across studies and offer suggestions for how OPCR can constructively be used in future research.
Topics: Humans; Tooth; Diet; Tooth Crown; Tooth Wear; Ecology
PubMed: 38306370
DOI: 10.1371/journal.pone.0292358 -
Journal of Endodontics Jan 2024Nonsurgical endodontic teeth treatment with severe pulp canal obliteration poses challenges, primarily locating canals. By combining 3-dimensional reconstruction and...
Nonsurgical endodontic teeth treatment with severe pulp canal obliteration poses challenges, primarily locating canals. By combining 3-dimensional reconstruction and spatial location registration, the dynamic navigation technique uses an optical tracking system to guide the clinician to drill in real time according to the predesigned path until access to the canal is established. Several in vitro studies and case reports have shown that calcified canal location with dynamic navigation system (DNS) is more accurate and efficient, yet the technique has limitations. In 4 cases with 7 teeth, this work presents manipulation process and clinical outcomes of DNS helping in calcified canal location. We performed handpiece adaptation and elucidated the failure to locate the canals with DNS in 2 teeth, resulting in canal geometry alteration and canal path deviation. Subsequently, the more experienced endodontist located the canals by combining cone-beam computed tomographic imaging and dental operating microscopy. All patients were completely asymptomatic after treatment. At the 1-year follow-up visit, the bone healing of periapical lesions progressed well according to the periapical radiography or cone-beam computed tomographic imaging. These findings indicate that DNS is a promising technique for locating calcified canals; however, it needs to be refined before clinical use.
Topics: Humans; Dental Pulp Cavity; Cone-Beam Computed Tomography; Molar; Dental Care; Root Canal Therapy
PubMed: 37890613
DOI: 10.1016/j.joen.2023.10.010