Mandibular Arcade Research Articles

Comparison of blind, ultrasound‐ and neurostimulator‐guided methods of percutaneous inferior alveolar nerve block

SummaryBackgroundAn inferior alveolar nerve block is often utilised for anaesthesia of the mandibular arcade of teeth prior to dental procedures. It has been described with multiple approaches and methods; however, at the current time, no direct comparison of percutaneous methods is available.ObjectivesTo compare the accuracy of percutaneous infiltration of the inferior alveolar nerve with a ventral blind approach (control) to blind caudal approach, ultrasound‐guided and neurostimulator‐guided methods.Study designProspective comparison of methods using anaesthetised horses prior to euthanasia or cadavers, being utilised for another study.MethodsAn 18 G spinal needle was used to inject a volume of 1 ml, composed of 0.5 ml of methylene blue and 0.5 ml of iodinated CT contrast medium, with placement guided by the aforementioned methods. Following injection the needle was left in place, CT‐imaging was performed and then the skulls were dissected. CT enabled assessment of the coverage of the mandibular foramen with contrast medium and distance of the needle tip from the mandibular foramen and dissection enabled assessment of the staining of the inferior alveolar nerve and lingual nerve.ResultsThe highest percentage of contrast staining of the inferior alveolar nerve and coverage of the mandibular foramen at CT was achieved with caudal blind and ultrasound‐guided approaches; however, no group reached a significant difference to control (ventral blind approach). Concurrent staining of the lingual nerve (possibly associated with undesired side effects) had high incidence and was similar between groups.Main limitationsUse of horses under anaesthesia/cadavers does not replicate clinical conditions and staining/coverage is assumed to relate to a clinically effective block.ConclusionsUltrasound‐guided and caudal approaches did have increased percentage of successful staining, but neither reached significance compared to the ventral blind approach.

Ossifying Epulis in a Thoroughbred Foal

A 4-month-old female thoroughbred foal was presented with large mass on mandibular gingiva. The enlarged mass was firm and yellowish pink in color, and occupied the whole mandibular arcade. The filly could not close her mouth with her lips. Radiographs showed radioopaque mass under the mandible. The mass was surgically excised from mandible. Histopathologically, gingival mass was characterized by hyperplastic gingival epithelium, well vascularized collagenous stroma and large area of bony tissues. Based on the gross and histopathologic findings, this case was diagnosed as ossifying epulis in the mandibular gingiva. This is the first report of ossifying epulis in a thoroughbred horse in Korea.

Endodontic treatment of a mandibular premolar abscess in a horse: A case study

SummaryA pulpar abscess of cheek tooth 307 (according to the Triadan numerical system) was diagnosed in a 7‐year‐old female Quarter Horse. History included a painful response to palpation in the mandibular region for approximately 4 weeks. Symptoms included swelling of the mandibular bone with subsequent fistulisation. A complete intraoral examination was performed and no lesions or abnormalities were found. Digital radiographs of the mandibular arcade demonstrated a periapical lesion of cheek tooth 307. Various therapeutic options were considered, including standing oral extraction, retrograde repulsion and endodontic therapy. Together with the client, a decision was made to perform endodontic therapy, with the double aim of preserving the tooth and maintaining normal molar occlusion. This was done under general anaesthesia without apicectomy, and using materials commonly used in the field of human endodontics. Following surgery, radiographs were taken and confirmed the complete sealing of the pulp canals. Recovery was uneventful and no post operative complications were observed. A complete intraoral follow‐up examination was performed one year after surgery, and revealed normal eruption and occlusion of the tooth involved. Radiographic examination confirmed the correct position and integrity of the sealant material, as well as normal perialveolar bone structure. This case report indicates that endodontic therapy, following the above protocol, involving pulpectomy and sealing of the pulp cavity, represents a valid alternative to the more commonly used technique of tooth extraction.

Apocrine Gland Hyperplasia in an 11-year-old Rabbit ( Oryctolagus cuniculus)

A 2-kg, 11-year-old neutered male rabbit ( Oryctolagus cuniculus) was presented for examination of a mandibular swelling. On clinical examination, 2 well-defined subcutaneous masses (15 mm and 5 mm in diameter) were identified along the ventral area of the left horizontal ramus of the mandible. An intraoral examination revealed a moderately elongated first premolar located within the left mandibular arcade. The mandibular masses were removed through surgical excision and coronal reduction was performed on the first left lower premolar. The 2 masses were isolated from the underlying tissue and there was no evidence of involvement of the abnormal tissue with structures comprising the oral cavity. The histological examination of the excised tissue revealed unencapsulated cystic, multiloculated and multilobulated masses consisting of numerous, variably sized cystic spaces and tubules supported by a moderately dense fibrovascular stroma. The final disease diagnosis of the mandibular tissue masses was cystic apocrine gland adenomatous hyperplasia, most likely of sweat gland origin. Apocrine gland hyperplasia is a benign, nonneoplastic lesion. The etiology of cystic hyperplasia of the apocrine glands is unknown in domestic species, but it is reported to occur in male dogs and less frequently in cats. This case is believed to be the first description of apocrine gland hyperplasia in the submandibular region of a rabbit.

The incidence and distribution of peripheral caries in the cheek teeth of horses and its association with diastemata and gingival recession

Although considered relatively common in horses, there is little information on the prevalence, distribution and aetiology of peripheral caries of the equine cheek teeth (CT). The objective of this study was to investigate a possible association between this lesion and diastemata or 'gaps' between the CT which facilitate the entrapment of food material. Video recordings of oroscopic examinations of all dental cases at an equine hospital over a 3-year period were reviewed, and the location of all diastemata, peripheral caries, trapped food, and of gingival recession were recorded. A total of 108 cases met study inclusion criteria and 298 diastemata and 445 CT with peripheral caries were noted. Diastemata were found predominantly in the mandibular arcades (80%) and 75% of animals had at least one diastema. Peripheral caries was uniformly distributed between the maxillary and mandibular CT, being most prevalent on the most caudal three teeth (87%). Overall, diastemata were not associated with peripheral caries at either a tooth or individual patient level. However, a highly significant association was found between the presence of trapped food within diastemata and gingival recession.

How to Radiograph the Erupted (Clinical) Crown of Equine Cheek Teeth

Diseases of the erupted (clinical) crown are being recognized with increasing frequency. Conventional “closed mouth” radiographic projections of the cheek teeth allow only limited evaluation of the erupted crowns and occlusal surfaces, due to superimposition of the opposing arcade. Open-mouthed oblique (OMO) radiographic projections are taken with a gag placed between the incisors, thus separating the maxillary and mandibular arcades and allowing more accurate assessment of the erupted crowns. They can therefore highlight lesions that are not visible on standard oblique views. The use of these techniques in clinical cases has proved to be of great value in diagnosing and evaluating lesions of the erupted crown, such as diastemata, abnormalities of eruption and wear, and coronal fractures. The open-mouthed 15° ventrolateral–lateral oblique gives an optimal view of the erupted crowns of the maxillary cheek teeth, and the open-mouthed 10° dorsolateral–lateral oblique optimally images the corresponding area of the mandibular arcades.

Observations of the cheek tooth occlusal angle in the horse.

The angle of occlusion was evaluated in 230 mandibular cheek teeth from 21 horses. There was no significant relationship between horse condition (sedated, anesthetized, dead) and measurement of mean cheek tooth occlusal angle. Cheek tooth occlusal angle was not significantly affected by the position of the tooth in the mandibular arcade or tooth age. The measurement of individual mandibular cheek tooth occlusal angles was predictive for occlusal angle of the entire mouth. Multiple variations of the incisor separation angle technique were predictive of cheek tooth molar occlusal angle for the measured arcade and the entire mouth but was significantly different contralaterally, suggesting that the single tooth method may be preferred. However, despite the limitations of the relatively simple incisor separation angle technique, it may provide the equine veterinary dentist a rapid method of assessing cheek tooth occlusal angle to ensure proper dental floating methods and outcomes.

Nonmetric Subadult Skeletal Sexing Traits: I. A Blind Test of the Accuracy of Eight Previously Proposed Methods Using Prehistoric Known-Sex Mummies from Northern Chile

While a number of nonmetric sex-related traits have been proposed, the accurate assignment of sex to subadult skeletal materials is generally considered problematic. Eight previously proposed nonmetric traits of the ilia and mandible have been demonstrated by other researchers to be related to the known-sex of subadults, yet there has been relatively little research attempting to evaluate the utility of these traits using independent collections of known-sex subadult skeletal remains. These eight traits include: elevation of the auricular surface, angle of the greater sciatic notch, depth of the greater sciatic notch, the "arch criteria," curvature of the iliac crest, gonial eversion, mandibular protrusion, and mandibular arcade shape. The present study blindly tested these eight nonmetric traits using 85 autopsied prehistoric known-sex mummified subadult remains from northern Chile that range in age between newborn and 15 skeletal years of age. The two primary questions examined for each trait are: (1) are the different character states for each of the eight traits related to known-sex, and (2) which of the eight traits are accurate enough for use in forensic cases? These questions are examined for each trait by both sex and age class so as to uncover potential sex- and age-related strengths and weaknesses for each of the characteristics. The results indicate that all eight of the previously proposed subadult sex-related traits are indeed related to known-sex, but that there is a great deal of variation by both sex and age in terms of the strength of congruent sex-related associations. With the exception of gonial eversion, all of the traits produced statistically significant chi2 values for their associations with known-sex when all subadult remains were considered. However, when all subadults are considered, only four traits demonstrated acceptable levels of accuracy for forensic applications. These traits include the arch criteria (82.3%), angle of the sciatic notch (80.7%), depth of the sciatic notch (79.0%), and mandibular arcade shape (77.6%). For subadults ranging in age from newborn to five skeletal years of age, only depth of the sciatic notch (81.5%) and the arch criteria (81.5%) approach acceptable levels of accuracy for use in forensic cases. The implications of these results are discussed and recommendations for bioarchaeological and forensic applications are made.

The mixed dentition and associated skull fragments of a juvenile fossil hominid from Sterkfontein, South Africa.

In April-May 1983, the late A.R. Hughes and his field team recovered more than 40 bone fragments and teeth from a single solution pocket of the Sterkfontein Formation. After preparation and reconstruction by JMC, it was recognised that these fragments represent a single juvenile individual (Stw 151), consisting of more than 40 cranial and dental parts, with mixed dentition. It constitutes the most complete set of jaws and teeth of an early hominid child since the Taung child was recovered in 1924. In this paper, the morphological and metrical features of the individual teeth are described. The other associated skull fragments (right ramus of the mandible, left petrous bone, right glenoid region) are also described. Comparisons are made with other South (and East) African fossil hominids. The beautiful preservation simultaneously of most of the deciduous teeth and of the permanent teeth exposed in their crypts allows an accurate analysis of the developmental sequence. A report on the dental developmental status of this juvenile is presented. On the basis of the microanatomical study of the developing permanent teeth, the estimated age at death is 5.2-5.3 years. Reconstructions of the maxillary and mandibular arcades are also offered. The morphological and metrical features of Stw 151 raise the possibility that it may represent a hominid more derived towards an early Homo condition than the rest of the A. africanus sample from Member 4.

The mixed dentition and associated skull fragments of a juvenile fossil hominid from Sterkfontein, South Africa

In April–May 1983, the late A.R. Hughes and his field team recovered more than 40 bone fragments and teeth from a single solution pocket of the Sterkfontein Formation. After preparation and reconstruction by JMC, it was recognised that these fragments represent a single juvenile individual (Stw 151), consisting of more than 40 cranial and dental parts, with mixed dentition. It constitutes the most complete set of jaws and teeth of an early hominid child since the Taung child was recovered in 1924. In this paper, the morphological and metrical features of the individual teeth are described. The other associated skull fragments (right ramus of the mandible, left petrous bone, right glenoid region) are also described. Comparisons are made with other South (and East) African fossil hominids. The beautiful preservation simultaneously of most of the deciduous teeth and of the permanent teeth exposed in their crypts allows an accurate analysis of the developmental sequence. A report on the dental developmental status of this juvenile is presented. On the basis of the microanatomical study of the developing permanent teeth, the estimated age at death is 5.2–5.3 years. Reconstructions of the maxillary and mandibular arcades are also offered. The morphological and metrical features of Stw 151 raise the possibility that it may represent a hominid more derived towards an early Homo condition than the rest of the A. africanus sample from Member 4. Am J Phys Anthropol 106:425–465, 1998. © 1998 Wiley-Liss, Inc.

Morphometric study of the evolution of mandibular arcades

Using a novel method to determine the co-ordinates of characteristic points, size and shape of mandibular dental arcades of fossil hominids are statistically analyzed and evaluated as a function of geological age. A strict linear relation between the dimensions of the arcade and the logarithm of the geological age is found. A similar law holds for angles calculated from the characteristic points. The results are discussed in terms of a continuous evolution from Homo erectus to modern man.