Maxillary Arcade Research Articles

The bacteriome of the oral cavity in healthy dogs and dogs with periodontal disease.

To compare the bacteriome of the oral cavity in healthy dogs and dogs with various stages of periodontal disease. Dogs without periodontal disease (n = 12) or with mild (10), moderate (19), or severe (10) periodontal disease. The maxillary arcade of each dog was sampled with a sterile swab, and swabs were submitted for next-generation DNA sequencing targeting the V1-V3 region of the 16S rRNA gene. 714 bacterial species from 177 families were identified. The 3 most frequently found bacterial species were Actinomyces sp (48/51 samples), Porphyromonas cangingivalis (47/51 samples), and a Campylobacter sp (48/51 samples). The most abundant species were P cangingivalis, Porphyromonas gulae, and an undefined Porphyromonas sp. Porphyromonas cangingivalis and Campylobacter sp were part of the core microbiome shared among the 4 groups, and P gulae, which was significantly enriched in dogs with severe periodontal disease, was part of the core microbiome shared between all groups except dogs without periodontal disease. Christensenellaceae sp, Bacteroidales sp, Family XIII sp, Methanobrevibacter oralis, Peptostreptococcus canis, and Tannerella sp formed a unique core microbiome in dogs with severe periodontal disease. Results highlighted that in dogs, potential pathogens can be common members of the oral cavity bacteriome in the absence of disease, and changes in the relative abundance of certain members of the bacteriome can be associated with severity of periodontal disease. Future studies may aim to determine whether these changes are the cause or result of periodontal disease or the host immune response.

The mycobiome of the oral cavity in healthy dogs and dogs with periodontal disease.

To investigate the mycobiome of the oral cavity in healthy dogs and dogs with various stages of periodontal disease. 51 dogs without periodontal disease (n = 12) or with mild (10), moderate (19), or severe (10) periodontal disease. The whole maxillary arcade of each dog was sampled with a sterile swab, and swabs were submitted for next-generation DNA sequencing targeting the internal transcribed spacer 2 region with a commercial sequencing platform. Fungi were detected in all samples, with a total of 320 fungal species from 135 families detected in the data set. No single fungal species was found in all samples. The 3 most frequently found fungal species were Cladosporium sp (46/51 samples), Malassezia restricta (44/51 samples), and Malassezia arunalokei (36/51 samples). Certain fungi, specifically those of the family Didymellaceae, the family Irpicaceae, and the order Pleosporales, were significantly associated with different stages of periodontitis. Mycobial analysis indicated that Cladosporium sp could be considered part of the core oral cavity mycobiome. Results highlighted that fungi are present in the oral cavity of dogs and are characterized by substantial species diversity, with different fungal communities associated with various stages of periodontal disease. The next-generation DNA sequencing used in the present study revealed substantially more species of fungi than previous culture-based studies.

Congenital hypodontia in three horses diagnosed by computed tomography

SummaryDental agenesis is a congenital disease defined as failure of formation of one or more teeth, which has been extensively described in human literature and that has been documented in several other species including cats, dogs, seals and sea lions, mice, and ungulates. The aim of this study was to review the clinical and computed tomographic (CT) features of tooth agenesis in a population of horses. Retrospective review of the imaging records from the Langford Equine Hospital was performed, including all horses that underwent head CT between January 2015 and June 2017. Of a total number of 167 CT scans, three horses with hypodontia were found. All three cases had agenesis of the maxillary 08s and one case had additional agenesis of the 307 and 308 teeth. Delayed resorption of the corresponding deciduous teeth was reported in all cases. The empty space left by the absent teeth was filled either by heterogeneous bone tissue alone (two cases) or by a combination of bone and soft tissue (one case). Alignment between teeth was preserved, and there was no displacement of the neighbouring teeth adjacent to the agenesis site. All three horses presented a symmetric pattern of dental agenesis within the maxillary arcades. The maxillary 08s, which are the latest to erupt, were the most affected teeth. This was similar to that reported in human literature, where the teeth that form later during development are the most vulnerable to dental agenesis.

Prevalence and analysis of equine periodontal disease, diastemata and peripheral caries in a first-opinion horse population in the UK

Equine dental disease remains a widespread affliction in domestic horses, with the potential to cause significant welfare problems. This retrospective study aimed to increase understanding of this aspect of equine health by examining dental records of 932 horses, taken from a 1-year period of first-opinion practice in south-western England and southern Wales. Three grossly-identifiable dental diseases were analysed: equine periodontal disease, diastemata and peripheral caries.The prevalence of active periodontal disease, diastemata and peripheral caries were 13.9%, 8.7% and 8.2%, respectively. Periodontal disease was more common in the mandibular than maxillary arcades (P<0.001) and in the premolar (06–08) than molar (09–11) cheek teeth (P<0.001). Diastemata were also observed more frequently in the mandibular than the maxillary arcades (P<0.001) and in premolar than molar cheek teeth (P<0.001). Peripheral caries were significantly more common in molar than premolar cheek teeth (P<0.001). A positive association was demonstrated between periodontal disease and diastemata (Exp(B)=4.22; P<0.001). Increasing age was a significant risk factor for periodontal disease (P<0.001) and diastemata (P<0.001). Sex was not conclusively established as a risk factor for any dental disease.

Morphological trends in arcade shape and size in Middle Pleistocene Homo.

Middle Pleistocene fossil hominins, often summarized as Homo heidelbergensis sensu lato, are difficult to interpret due to a fragmentary fossil record and ambiguous combinations of primitive and derived characters. Here, we focus on one aspect of facial shape and analyze shape variation of the dental arcades of these fossils together with other Homo individuals. Three-dimensional landmark data were collected on computed tomographic scans and surface scans of Middle Pleistocene fossil hominins (n = 8), Homo erectus s.l. (n = 4), Homo antecessor (n = 1), Homo neanderthalensis (n = 13), recent (n = 52) and fossil (n = 19) Homo sapiens. To increase sample size, we used multiple multivariate regression to reconstruct complementary arches for isolated mandibles, and explored size and shape differences among maxillary arcades. The shape of the dental arcade in H. erectus s.l. and H. antecessor differs markedly from both Neanderthals and H. sapiens. The latter two show subtle but consistent differences in arcade length and width. Shape variation among Middle Pleistocene fossil hominins does not exceed the amount of variation of other species, but includes individuals with more primitive and more derived morphology, all more similar to Neanderthals and H. sapiens than to H. erectus s.l. Although our results cannot reject the hypothesis that the Middle Pleistocene fossil hominins belong to a single species, their shape variation comprises a more primitive morph that represents a likely candidate for the shape of the last common ancestor of Neanderthals and H. sapiens, and a more derived morph resembling Neanderthals. The arcade shape difference between Neanderthals and H. sapiens might be related to different ways to withstand mechanical stress.

Bilateral Asymmetry of Upper Permanent Dentition in Six Archeological Pre-Conquest Samples from Colombia, South America

Bilateral asymmetry is an important fieldof study in physical anthropology. The present studyevaluated the frequencies of bilateral asymmetry of fourtraits (one for each tooth type in the maxillary arcade)in six pre-Conquest human archeological samples fromColombia, South America. Results show the importanceof a preliminary analysis of bilateral asymmetry inarcheological fragmented samples and its relevance inmolding subsequent interpretations.

A New Salamander from the Late Paleocene—Early Eocene of Ukraine

A new neotenic salamander, Seminobatrachus boltyschkensis gen. et sp. nov., is described based on 14 skeletons of late Paleocene—early Eocene age preserved on drill core slabs from the Cherkassy Region, central Ukraine. The new taxon is diagnosed by the following unique combination of characters: dorsal process of premaxilla posteriorly elongate and overlaps frontal; maxilla greatly reduced in size; parietal—squamosal contact absent; vomerine tooth row long and parallel to maxillary arcade; pterygoid has long anterior process; quadrate ossified; marginal and palatal teeth pedicellate; trunk vertebrae amphicoelous, each having a subcentral keel, anterior basapophysis, and spinal nerve foramina; ribs bicipital; carpals and tarsals unossified; and phalangeal formulae of 2-2-3-2 and 2-2-3-4-2 for manus and pes, respectively. Phylogenetic analysis nests S. boltyschkensis within Urodela (i.e., crown-clade salamanders), but its exact phylogenetic position is equivocal, resolving in one of three ways: (1) in an u...

New species of Cercopithecoides from Haasgat, North West Province, South Africa

Analyses of new cercopithecid fossil specimens from the South African site of Haasgat point to craniofacial affinities with the genus Cercopithecoides. Detailed metric and non-metric comparisons with South African Cercopithecoides williamsi, and other East African Cercopithecoides species, Cercopithecoides kimeui, Cercopithecoides meaveae, Cercopithecoides kerioensis, and Cercopithecoides alemyehui demonstrate that the Haasgat fossils have distinct craniofacial morphology and dental metrics. Specifically, material from Haasgat probably represents one of the smaller Cercopithecoides, differing from the others in its particular suite of features that vary within the genus. It is unique in its more vertical ramus, associated with a relatively lengthened mandibular body. Haasgat Cercopithecoides has a particularly narrow interorbital region between relatively larger ovoid orbits, with articulation of the maxillary bones at a suture above the triangular nasal bones. Furthermore, the maxillary arcade is more rounded than other Cercopithecoides, converging at the M 2 and M 3. The conclusion drawn from this analysis is that the Pleistocene Haasgat fossils are colobines representing a distinct taxon of Cercopithecoides, Cercopithecoides haasgati, thus adding a second species of the genus to southern Africa.

Occlusal fissures of the equine cheek tooth: Prevalence, location and association with disease in 91 horses referred for dental investigation

Fissures of the occlusal surface of the equine cheek tooth are poorly understood and their association with dental disease is unknown. To describe the prevalence and location of occlusal fissures in the cheek teeth (CT) of a group of horses referred for dental investigation/treatment, and determine association with intercurrent dental disease. Digital video recordings of oral endoscopic examinations for all horses referred to the Rossdales Equine Hospital for dental investigation from November 2006 to June 2009 were reviewed. Location of occlusal fissures in relation to both Triadan tooth position and pulpar secondary dentine was recorded; direction of fissure and concurrent involvement of enamel was also documented. The CT location considered at the time of examination to be the primary site/s of disease was correlated with presence of fissures on these teeth. 91 cases meeting the inclusion criteria were identified. Occlusal fissures were documented in 58.2% (53/91) cases, with a total of 227 CT being affected. Fissures were most prevalent mid-arcade. The majority (92.1%) of fissures in maxillary CT were associated with the caudal palatal pulp horn. Fissures in mandibular CT were predominantly associated with the buccal pulp horns (95.7%). There was no significant difference in the median number of CT with fissures in relation to gender. There was no correlation between age (r(2)= 0.01) of horse and number of CT with fissures. A significantly greater number of CT with multiple occlusal fissures was found in mandibular compared to maxillary arcades. No correlation was found between presence of fissures and location of individual CT considered to be primarily responsible for presentation. Occlusal fissures in this group of animals were common and not correlated to primary site of dental disease. In horses subjected to dental investigation, occlusal fissures of the cheek teeth should not be considered an indicator of tooth compromise. Location and direction of fissure propagation in most cases is inconsistent with occlusal fissures being causally implicated in slab fractures of cheek teeth, although site predilection may indicate a possible association with masticatory forces.

A new Early Cretaceous salamander ( Regalerpeton weichangensis gen. et sp. nov.) from the Huajiying Formation of northeastern China

Recent discoveries of well-preserved Late Jurassic and Early Cretaceous salamander fossils from China are helping to resolve highly controversial aspects of caudate phylogeny. Here we report on a new Early Cretaceous salamander, Regalerpeton weichangensis gen. et sp. nov., from the Huajiying Formation in Hebei Province, China. This specimen is characterized by long, arched vomerine tooth rows running parallel to the maxillary arcade; a long and tapered anterior ramus of the pterygoid that curves anteromedially; an ossified hyobranchium with one pair of hypobranchials and two pairs of ceratobranchials; and scapulocoracoids with greatly expanded, approximately rectangular coracoid components. Phylogenic analysis places Regalerpeton as the sister group to a Cryptobranchidae clade including Chunerpeton, with Jeholotriton and Pangerpeton as successive sister taxa.

A new species of Phrynopus (Anura, Strabomantidae) from Peru, with comments on the osteology of the genus

A new, small species of Phrynopus is described from the eastern slopes of the Cordillera Oriental just north of the Río Huallaga in central Peru. The species resembles P. montium, but is distinguished from it and other congeners by its spatulate snout. The anterior end of the maxillary arcade is broadly rounded in dorsal view, and composed of wide premaxillae that bear extraordinarily large alary processes that are deflected posteriorly at an acute angle. The configuration of the premaxillae accounts for the wide, depressed snout in this species, which in other osteological features resembles P. montium. The osteology of Phrynopus montium is described in some detail in comparison to the new species, with the intention of establishing a baseline for future morphological studies and taxonomic descriptions of strabomantine anurans of this and related genera.

Variações anatômicas na dentição de cães sem raça definida

Foi avaliada a dentição de 100 cães adultos sem raça definida, machos e fêmeas, com o objetivo de investigar as variações anatômicas. A ausência congênita de molares foi observada em cães de pequeno porte; a ausência patológica predominou na região dos pré-molares; houve maior frequência de dentes supranumerários na arcada superior, predominando os molares; foram observadas raízes supranumerárias em pré-molares e molares superiores e inferiores; e grande número de raízes fusionadas, predominando no segundo pré-molar inferior.

Sequential cleft management with the sliding sulcus technique and alveolar extension palatoplasty.

Conventional methods of cleft lip repair deprive the anterior (buccolingual) alveolar mucoperiosteum of blood supply from the facial-internal maxillary arcade. Six months later, at palatoplasty, lingual incisions permanently isolate the lingual mucoperiosteum from its blood supply--the greater palatine artery. The osteogenic alveolar mucoperiosteum is thus converted from a richly supplied boundary zone between the two angiosomes into an isolated tissue dependent on osseus backflow. Cleft-sided growth disturbance is considered from this perspective. Subperiosteal techniques that preserve the blood supply to this tissue are considered in a sequential plan of cleft management.

Dentition of the Ground Skink, Scincella lateralis (Sauria, Scincidae)

Scanning electron microscopy was used to examine the morphology of the tooth crowns, and light microscopy was used to quantify the numbers and sizes of the teeth occurring on each of the major tooth-bearing bones of the ground skink, Scincella lateralis. In S. lateralis, monostichous, bicuspid teeth occur on the premaxilla, maxilla, and dentary but not on the pterygoid. No ontogenetic or sexual variation was observed in crown morphology. The sizes and numbers of teeth vary with respect to location, with dentary teeth much larger and more numerous than the teeth on the maxillary arcade. Body size was more frequently, positively correlated with tooth sizes and numbers than head width. In S. lateralis, a sexual dimorphism in the number of premaxillary teeth is present, and ontogenetic differences in tooth number and size also occur. This study represents the first complete description of

Larval and metamorphic skeletal development in the fast-developing frog Pyxicephalus adspersus (Anura, Ranidae)

, is exceptional among living frogs. Embryonic development, larval phase, and metamorphosis can be completed in 17 days at a temperature of 29°C. The metamorphosis only takes 5 days. The present study shows that, despite the unusually short larval phase in P. adspersus, the state of skeletal differentiation reached at the end of metamorphosis is similar to that of other frog species. There is no shift of cranial bone formation postmetamorphosis as could have been expected and is known from other species. The majority of compared species are particularly similar in the sequence of bone formation in the postcranial skeleton. However, there are clear differences among species in the timing of these events relative to the larval growth trajectory, absolute time, and certain developmental markers, such as external limb differentiation. For example, skeletogenesis and externally visible limb differentiation are only loosely integrated. Interspecific comparisons show that, in P. adspersus, the early onset of skeletal ossification is an unusual feature among frogs. Freshly metamorphosed froglets of P. adspersus are already distinct from comparable stages of other species in having strong jaws, fang-like teeth, and a squamosal-maxilla contact. The latter stabilizes the maxillary arcade and the suspensorium and might relate to the ability to catch and swallow very large vigorous prey, such as siblings, shortly after metamorphosis. The presence of a complete set of dermatocranial elements and postmetamorphic ossification of only the sphenethmoid and operculum are considered plesiomorphic features, whereas the much less completely ossified skulls of metamorphosed froglets, particularly in Bufo and Hamptophryne, are likely apo- morphic developmental traits within the Anura.

Periodontal bone loss in the aging beagle dog A radiographic study

Studies in the beagle dog have clearly established the usefulness of this breed in periodontal disease research. However, little is known about the progressive nature of the disease with advancing age. It is the purpose of this paper to describe frequency and distribution of radiographically detectable lesions in an aging population of 166 colony dogs. 3 grades of alveolar bone loss were determined on high-quality postmortem radiographs. The number of teeth involved was similar in male and female and was age-dependent. Disease was more frequent in the maxillary arcades, with the 2nd upper premolar most frequently involved. Most extensive bone loss was noted around the 3rd and 4th upper premolars, and 1st and 2nd lower molars. It is felt that by the study of such a large group of older colony dogs, a better understanding can be gained of the expected alveolar bone loss with age as determined radiographically.