Incisive Canal Research Articles

Intra-osseous squamous cell carcinoma of the maxilla: probably arisen from non-odontogenic epithelium

This paper reports a case of intra-osseous squamous cell carcinoma (IOSC) of the maxilla. The patient was a 52-year-old male with a chief complaint of swelling of his hard palate. The lesion was initially diagnosed as an incisive canal cyst from the clinical and radiographic findings, but histological examination revealed the lesion to be a poorly differentiated squamous cell carcinoma. The review of the literature yielded only a few previous cases of IOSC of the maxilla, which were probably of odontogenic origin. The present maxillary IOSC is thought to be non-odontogenic in origin.

Dental radiology and oral pathology

This article represents an overview of normal and pathological findings of the oral structures for the practicing radiologist. Some of the disease processes discussed are of dental etiology, whereas others are manifestations of systemic diseases. Normal tooth development is described followed by an overview of radiolucent, radiopaque, and mixed lucent-opaque lesions. In the radiolucent category, normal anatomical landmarks of the jaws include the mental foramen, mandibular canal, incisive canal and maxillary sinuses. Other lucencies that represent normal structures or variations include developing tooth buds and root apices, healing dental extraction sites, prominent submandibular fossae and nutrient canals. In the radiopaque category, normal anatomical landmarks of the jaws include the genial tubercle, mental ridge, external oblique ridge, walls of the submandibular canal, walls of the maxillary sinus, nasal septum, stylohyoid ligament, and zygomatic process. Other opacities that represent normal structures or variations include dental restoration material, dental endodontic material, retained roots, sialoliths, salivary duct calculi, calcified lymph nodes, recent extraction sites, hypercementosis, and foreign bodies. Pathological entities which present radiographically as lucencies, opacities, and mixed lucent-opaque areas include inflammatory lesions, cysts, fibro-osseous disease, benign neoplasms, malignant neoplasms, and lesions secondary to metabolic disorders.

Microvascular Architecture of the Palatine Mucosa in the Common Squirrel Monkey (Saimiri sciureus)

Detailed observations were made of the structure and microvasculature of the palatine mucous membrane of the common squirrel monkey (Saimiri sciureus) by means of the plastic injection method under a scanning electron microscope. The findings obtained were compared with those of the Japanese monkey and other mammals. The osseous palate was flat horizontally and a pair of incisive foramina were apparently open at the anterior end of the hard palate. At the posterior end of the osseous palate, the pterygopalatine incisurae were found bilaterally. The incisive papilla was not obvious in form and size, and a pair of openings of the incisive canal were always situated on both sides of the papilla. The transverse palatine plicae or ridges numbered 7 or 8 symmetrically. They arched posterolaterally with an anterior protrusion near each median end. Posterior plicae were underdeveloped. Numerous openings of the palatine glands were found in the soft palatine mucosa. The arteries supplying the palate were the major palatine artery passing through the major palatine foramen and the soft palatine artery passing through the pterygopalatine incisura. The major palatine artery extended forwards giving off numerous medial and lateral branches, and its end on the respective side entered a small foramen located lateral to the incisive foramen. Medial and lateral branches formed the submucous arterial network. Arterioles diverging from this network were directed to the epithelial surface and formed an arterial network in the lamina propria. Further, capillaries diverging from the latter network built up the subepithelial capillary network immediately beneath the epithelium. Capillary loops sprouting from the capillary network were found in the form of a simple hair-pin without locational differences in their heights. The microvascular architecture thus displayed some similarity with that of the Japanese monkey. However, the vascular networks in the lamina propria and submucous layer were not distinct in size and scale as compared to those of the Japanese monkey. These differences may be related to the stature, living environment and food habits of this species.

Incisive canal and pterygopalatine fossa injection for hemostasis in septorhinoplasty

Incisive canal and pterygopalatine fossa injection for hemostasis in septorhinoplasty

A diagnostic case involving an incisive canal cyst

An incisive canal cyst was misdiagnosed as an endodontic lesion. The patient's chief complaint was pain on mastication with increasing intensity for the last 2 days. The single original periapical radiograph revealed a well-circumscribed radiolucency related to the apex of the maxillary right central incisor. The patient was referred with a request for endodontic therapy. A subsequent angled radiograph revealed an interroot location of the lesion, and pulp testing showed a normal response. The patient was then referred for surgical treatment. Following removal of the lesion, the histopathologic examination confirmed the diagnosis of an incisive canal cyst. One-year follow-up showed complete healing and maintained tooth vitality, and the patient was asymptomatic.

Computed Tomography in Dental Implantation Surgery

High-resolution thin section CT with cross-sectional oblique and panoramic CT reconstructions has been shown to be an excellent tool for the preoperative evaluation of the mandible and maxilla for dental implant surgery. Oblique cross-sections throughout the entire surgical field allow visualization of osseous topography as well as related internal anatomic structures such as the inferior alveolar canal, the mental foramina, the incisive canal, and the maxillary sinuses. Armed with this knowledge, the surgeon-restorative dentist team can plan fixture positioning more effectively, thereby minimizing surprises in the operating room. Cases with inadequate buccolingual bone dimension are not attempted, whereas many other cases that do not appear to have adequate bone, as seen on conventional x-ray films, can be successfully implanted. The ultimate prosthesis is optimized because the surgeon can take full advantage of the available bone to achieve proper fixture alignment. It is quite likely that as future experience is obtained with maxillofacial CT, it may also be useful in diagnosis and treatment for a wide variety of other disorders of the jaw.

Elastic cartilage in the incisive canal region: Report of a case

A man complained persistently of ‘gritty bits’ coming into his mouth from behind the upper front teeth over a period of 10 years. Elastic cartilage was found within fibrous connective tissue of the incisive papilla region and it is suggested that transepidermal elimination of elastotic material, as happens in perforating dermatoses, was responsible for this patients complaint.

鼻口蓋管嚢胞の２例

Two cases of nasopalatine duct cyst were investigated clinically and histopathologically. The patients were 47 and 29 year-old females. Inflammatory symptoms were seen in the labial gingiva of the upper front teeth and the middle part of the palate. In X-ray findings, there was a pear-shaped or heart-shaped X-ray image the size of the tip of the little finger in the area corresponding to the incisive canal. In the operative findings, there was a cyst in the incisive canal in each case, and adhesion between the cystic wall and the nasopalatine nerve. There was no relation between the cysts and the apexes of the central incisors. In the histopathological findings, the cystic wall consisted of stratified epithelium in both cases, and there was also some ciliated pseudostratified epithelium in one case. There was subcutaneous infiltration of inflammatory cells, as well as nerve tissue in one case and a vessel in one case.

Descriptions of anatomical differences between skulls and mandibles ofEquus zebraandE. burchellifrom Southern Africa

The external anatomical differences between the skulls and mandibles of 10 mountain zebras Equus zebra and 10 plains zebras E. burchelli of both sexes were studied. The nomenclature used conforms to Nomina Anatomica Veterinaria (1983). Eleven structural differences are described for the first time and illustrated, viz., outline of the foramen magnum; length of the alar canal; comparative presence of the For. alare parvum; proportions of the mastoid process of the temporal bone; shape and development of the pterygoid crest; notch at the rostral end of the facial crest in E. burchelli; different inclination of the caudal end of the zygomatic arch; shape and length of the retroarticular process; relative size of the supraorbital foramina; presence of incisive canals in E. zebra; difference in the junction of the interalveolar border of the mandible with the alveolar border of the first cheek tooth. If three or more differences are used for identification, it should be possible to train any worker to distinguish between the skulls of these two species.

Substance-P-Containing Fibers in the Incisive Papillae of the Rat Hard Palate

Substance P (SP)-containing fibers in the incisive papillae of rat hard palates, which include various components of sensory receptors, i.e. mechanoreceptors, free nerve endings and chemosensory corpuscles (taste buds), were examined using immunoperoxidase techniques and light and electron microscopes. Immunolabeled fibers were consistently distributed in the medial part of the orifice of the incisive canals, i.e. in the taste-bud-enriched region. Dense immunolabeled fibers were found in subgemmal regions and in the lamina propria papillae. Some fine fibers entered and ascended the taste buds or occasionally the epithelium outside the taste buds. In addition, a rich innervation by SP-containing fibers close to blood capillaries was clearly identified. Electron microscopy revealed no specialized synaptic contact between the immunolabeled fibers and taste bud cells. Synaptic-like images could be found only between nonimmunolabeled nerve endings and the underlying taste bud cells. In the lamina propria papillae, mechanoreceptors observed in the present study contained no immunoperoxidase end products, whereas free nerve endings with an immunolabeled small-diameter axon (630-730 nm in diameter) were frequent. Similar axons were located at the adventitia of the blood capillaries. The possible functional role of SP-containing fibers in the incisive papillae was given attention.

An immunocytochemical study of the inflammatory cell infiltrate and epithelial expression of HLA-DR in odontogenic cysts.

The presence and distribution of lymphocytes, Langerhans cells, HLA-DR+ infiltrating cells and the expression of HLA-DR by lining epithelium was investigated in the walls of odontogenic cysts using an indirect immunoperoxidase method on acetone-fixed cryostat sections. The 23 cysts studied consisted of 14 dental (radicular) cysts, 5 keratocysts, 2 dentigerous cysts, 1 surgical ciliated cyst and 1 incisive canal cyst. The cell populations detected in the walls of all cysts were similar and consisted of HLA-DR+ macrophage-type cells and a mixture of T and B lymphocytes. Analysis of the T cell subsets revealed that in all cases the CD4+, Th/i subset predominated over the CD8+, Ts/c subset. 18/22 cyst linings contained cells expressing a Langerhans cell phenotype (CD1+). Cytoplasmic epithelial expression of HLA-DR was detected in 7/22 specimens. Neither the presence of HLA-DR+ epithelial cells nor LC were restricted to a given type of cyst. These findings indicate the occurrence of similar cellular processes irrespective of the proposed developmental or inflammatory aetiology of these lesions.

CT scan prior to installation of osseointegrated implants in the maxilla

A method using computed tomography (CT) for evaluation of maxillary structures before installation of titanium fixtures is described. This method gives us comprehensive information of relevant bony structures and bone quality. The width of the paranasal sinuses, nasal cavity and incisal canal is properly evaluated and the method facilitates measurements of available space for position, number and length of fixtures to be installed.

正中口蓋部に発生した非角化性原始性嚢胞の１例とその文献的考察

In recent years, there has been some controversy concerning the relation between primordial cyst and odontogenic kerato cyst and a definite conclusion has not been obtained yet.Further, due to vague criteria of diagnosis for fissural cyst, classification of jaw cyst seems to be confused.We experienced a patient who underwent several examinations under clinical diagnosis of fissural cyst and finally diagnosed as non-keratinizing primordial cyst.Thus, we describe on an outline of this case addiscuss the classification of jaw cyst.The patient was a 25-year-old female who visited our hospital with chief complaint of pain of median palate. Examination revealed a relatively discrete swelling about pigeon egg size in the median palate from which a fluid with pus cells was aspirated.X-ray findings revealed a discrete, pear-shaped, bone radiolucent picture about pigeon egg size in the region between the bilateral median incisal teeth and the hard palate, and bilateral inflammation of the central incisor root spread centrifugally. Under a clinical diagnosis of fissural cyst, cystectomy was conducted under local anesthesia on December 21, 1984. Histopathological findings revealed that the cystic wall was thin and the epithelial layer consisted of stratified squamous epithelium. Loss of epithelial projection to the subepithelium and alignment of the cylindrical basal cells in the lowest layer of epithelium were noted. Abcess and hemorrhagic nest as well as cellular infiltration with severe inflammation were observed in the subepithelium. The epithelium was invaded by inflammation and epithelial alignment was disturbed. Namely, an established diagnosis of non-keratinizing primordial cyst was made from the following points: 1) pathological findings accorded with the findings of primordial epithelium, 2) no relation between this lesion and the incisal canal was observed from the findings during operation, 3) the lesion was distinguished from nasopalatine cyst, 4) there was no definite evidence to diagnose fissural cyst and 5) there was full significance of existence of non-keratinizing primordial cyst, In this paper, we further discussed the classification of jaw cyst.

上顎正中部に生じた嚢胞の臨床病理組織学的検討

Clinical and histological characteristics of 19 cysts that occurred symmetrically in the anterior portion of the midline maxilla were studied. Radicular cysts in the incisal region were excluded because they did not fit to the above category.Twelve were non-dentigerous developmental cysts and palatal swelling was found more often than in the other group of cysts with an unerupted supernumerary tooth, and the bony defect of the palate was noted in 11 cases.Radiographically, nasopalatine duct cyst was suspected in 8 cases, but the other 4 cysts presented the features consistent with those of median palatine cyst and in one the normal structure of the incisal canal was clearly recognized in the cystic radiolucency, although the relationship was confirmed at operation. Pseudostratified ciliated columnar epithelium was the main lining element in 8 cases.Mucous cells and Goblet cells were frequently seen. Neurovascular bundles were found in 8 cases and the subepithelial blood vessels were arranged parallel to the epithelial layer.Diagnosis of nasopalatine duct cyst was suspected in all cases.The other 7 cysts were dentigerous cysts with a swelling on the labial aspect of the anterior maxilla.The lining epithelium was stratified squamous epithelium and mucous cells and neurovascular bundles were noted in 2 cases, but differential diagnosis was easy because of the presence of the crown of an unerupted tooth in the cystic cavity.The results indicate that the cyst occurring symmetrically in the anterior portion of the midline maxilla is either nasopalatine duct cyst or dentigerous cyst and the possibility of median palatine cyst or radicular cyst is comparatively low.

Sensory nerve endings of the incisive papilla of rat hard palate studied by peroxidase cytochemical methods.

This study utilized peroxidase cytochemical methods to survey and analyze the distribution, morphology, and functional relationship of the various components of sensory nerve endings in a focal region of the anterior hard palate (incisive papilla) of the rat. The studies included an anatomical survey of this relatively unknown oral structure, confirmation of the trigeminal origin (labeled by retrograde axonal transport of WGA-HRP injected into the incisive papilla) of the sensory nerve endings, and a complete analysis of the distribution of these nerve endings (labeled by anterograde axonal transport of HRP or WGA-HRP injected into the trigeminal ganglion). Three methods of fixation and two methods of cytochemical reaction were used for selection of an optimal technique for these studies. The results showed distinct patterns of peroxidase-labeled sensory nerve endings at three regions of the incisive papilla: a) dome region (ventral), where labeled nerve endings formed three parallel channels in association with three surface ridges; b) chemosensory corpuscle enriched region (medial to incisive canal), where 82% of the 30-40 chemosensory corpuscles were labeled; and c) lateral labium (lateral to incisive canal), where labeled nerve endings formed a circumscribed network guarding the orifice of incisive canal. The discrete organization of multiple sensory nerve endings in the incisive papilla of the rat may provide an easily accessible model system for various studies in sensory physiology.

Anterograde axonal transport and intercellular transfer of WGA-HRP in trigeminal-innervated sensory receptors of rat incisive papilla.

The ultrastructure and identification of WGA-HRP-labeled sensory receptors in the rat incisive papilla (the most anterior part of hard palate) were studied using semiserial thin sections. Various sensory receptors were organized according to three locations: dome region (ventral), chemosensory corpuscle region (medial to orifice of incisive canal), and lateral labium (apposing the incisive canal). In the dome region, the sensory receptors were localized in three sensory zones that were associated with surface ridges (one medial and two lateral). In each of these zones, intraepithelial receptor axons and Merkel receptors occurred in the epithelium, while simple unencapsulated corpuscles, glomerular-Meissner corpuscles, and incisive (encapsulated) corpuscles occurred in the lamina propria. In the chemosensory corpuscle region, chemosensory corpuscles and intraepithelial receptor axons were located in the epithelium, and incisive corpuscles were present in the lamina propria. In the lateral labium, only intraepithelial receptor axons were prominent. In all these sensory receptors, the preterminal axons and axon terminals were labeled with the tracer protein. In addition, some nonneuronal cells closely associated with the axon terminals were selectively labeled, e.g., terminal Schwann cells, lamellar Schwann cells, Merkel cells, corpuscular basal cells and chemosensory cells. Other adjacent cells were not labeled, e.g., unspecialized epithelial cells, capsular cells, corpuscular sustentacular cells, and fibroblasts. In both labeled axons and cells, WGA-HRP was incorporated into vesicles, tubules, and vacuolar organelles. The specific intercellular transfer of tracer protein may indicate trophic interactions between axon terminals and support cells in sensory receptors. The specific organization of multiple sensory receptors in the rat incisive papilla may provide a useful alternative system for studying somatosensory physiology.

Odontogenic Infections

Nasopalatine canal (NPC) is an important anatomical structure present in the anterior mid maxilla. It has the synonyms of incisive canal or anterior palatine canal. The objective of this study was to identify the morphometric characteristics of the NPC in group of Sri Lankan people using Cone beam computer tomography (CBCT) and to determine normal morphological course and anatomical variations. Fifty Maxillary CBCT images of anterior maxilla, obtained from the archives of the University Dental Hospital, Peradeniya were retrospectively analyzed to determine the position of the NPC. Morphology, canal dimension of NPC and its relation to the maxilla. Majority had a single opening (48%) or 2 openings (46%). Average diameter of the canal was 3.692 mm with a range of 2–6 mm. Majority of the canals had funnel shape and were vertically curved. Average length of canal was 12.142 mm and angulations of the curvature was 115.6940. Average antero-posterior diameter at nasal fossa was 2.852 mm, at mid-palate 2.366 mm and at hard palate 3.034 mm. Our findings were different from the findings reported in the literature. This may be due to the differences in ethnicity or limited size of sample. Within the limits of this study, we conclude that the form of the NPC is variable; predominantly funnel shaped with a single or two openings and with an average diameter of 3.7 mm in Sri Lankan population. Identification of variations in the position and shape will help in clinical practice specially in introducing local anesthetic block injections during dental treatment.

Median palatine cyst

Median palatine cysts are rare, nonodontogenic lesion of the hard palate that do not involve the palatine papilla or incisive canal and that usually present as asymptomatic, fluctuant swellings. They may involve the floor the nasal cavity but are treated by simple enucleation, without recurrence. They are composed histologically of a fibrous collagenous tissue wall, with infiltration of chronic inflammatory cells, and lined by stratified squamous and/or respiratory epithelium. They are differentiated from the nasopalatine and other anterior maxillary cysts by the following diagnostic criteria: Appears grossly to be symmetrical along the midline of the hard palate. Located posterior to palatine papilla. Radiographically ovoid or circular in appearance. Not intimately associated with a nonvital tooth or found to have any communication with the incisive canal. Shows no histologic evidence of nerve trunks, large vascular spaces, hyaline cartilage, or accessory salivary gland tissue in the cyst wall.

Median palatine cyst: Report of a case with review of the literature

A case of median palatine cyst arising in a 28-year-old man with complaining of a midpalatal swelling was reported. Radiographic examination showed a small and round cystic radiolucent area in the middle palate. At the surgical operation, confirmatory evidence, both tooth-root and incisive canal were not involved in the lesion, was noted.In addition to the present case, clinico-pathological and embryological literatures of median palatine cyst were reviewed, though median palatine cyst has been neglected in the WHO classification of non-odontogenic cysts.

Palatal analysis and osteology of the hard palate of the Kenyan African skulls

One hundred twenty-five dry skulls from Kenya that consisted of about 90% Bantu individuals were examined to obtain data on the gross anatomy of the hard palate. The palatine index showed that 43.2% of the total sample of skulls has narrow (leptostaphyline), 23.7% intermediate (mesostaphyline), and 33.1% wide (brachystaphyline) palates. The palatine height index showed that 40% skulls had low (chamestaphyline), 57% intermediate (orthostaphyline), and 3.0% deep (hypsistaphyline) palates. Mean palatal length, breadth, and height for the total sample was 4.92 cm, 4.02 cm, and 1.22 cm, respectively. The incisive foramen and canal was cone shaped in 80% where the diameter of the foramen was less than 0.4 cm, while it was cylindrical in 20% where the diameter was greater than 0.4 cm. Forty-nine per cent of the skulls had two-five lesser palatine foramina present. The greater palatine foramen was found to lie at the level of the third molar in 76%, intermediate between second and third molars in 13.6%, and opposite the second molar in 10.4%. The greater palatine foramen opened antero-medially in 74% and perpendicularly in 26% of the palates. Extensive longitudinal palatal grooves were found bilaterally in all the palates, 70% showed divisions of the grooves, 63.2% had crests along the border of the grooves, and 19.2% had bridges in the posterior part of the groove near the opening of the greater palatine foramen. The incidence of palatine torus was 4.8%. The incisive suture was present in 6.4% of the adult palates.