Cellular profile of primary molars with pulp necrosis after treatment with antibiotic paste

The interradicular region of primary molars is permeated by many foramina, channels and accessories that connect the pulp cavity with the periapical tissues anatomically. Thus, pulp decomposition products or drugs used in endodontic treatment can trigger inflammatory reactions. The aim of this study was to evaluate the blood cell profile of the alveolar region after extraction of primary molars treated with CTZ paste. Forty-eight primary molars were selected with clinical and radiographic signs of extraction. The sample was divided into three groups with 16 teeth each: Group 1-healthy teeth; Group 2-untreated decayed teeth; and Group 3-teeth treated with CTZ paste. Immediately after the extraction, blood from the interface of the tooth socket was collected and smears were performed for further evaluation. The slides were stained by the Fast Panoptic® method and analysed by two previously trained examiners who counted the leucocytes in sets of 100 cells/slide, differentiating them into neutrophils, lymphocytes, monocytes, eosinophils and basophils. The data were analysed statistically by the MANOVA test. The blood samples from Group 2 differed significantly from Group 1 samples for all classes of leucocytes, except basophils, with higher average for lymphocytes (62.56), monocytes (7.81) and eosinophils (2.31). For Group 3, there was a relative difference (P < 0.05) to Group 2, of monocytes and eosinophils values. The blood cellularity interface in the tooth socket of primary teeth treated with CTZ paste is similar to those of healthy, exfoliated teeth and physiologically different from untreated decayed teeth.

Frequency and anatomy of the retromolar canal - implications for the dental practice

The retromolar canal (RMC) is an anatomical variant of the mandibular canal. Apart from blood vessels it also contains accessory nerve fibers and is clinically important, because its presence can account for failures of mandibular block anesthesias and in rare cases, injuries of its neurovascular bundle can lead to complications such as hemorrhages and dysesthesias. The aim of this retrospective case study was to analyze the frequency and anatomy of the RMC using cone beam computed tomography (CBCT) in order to draw conclusions for the dental practice. A total of 680 CBCT scans comprising 1,340 mandibular sides were evaluated. A total of 216 RMCs (16.12%) were found. The most common appearance of the canal (39.82%) corresponded to type Al (vertical course), whereas type C (horizontal course) occurred least often (6.02%). Mean measured values were 1.03 mm (SD=0.27mm) regarding the RMC diameter, 10.19 mm (SD=2.64mm) regarding the RMC height and 15.10 mm (SD=2.83 mm) regarding the distance of the RMC to the second molar. Neither demographic factors nor the spatial resolution of the CBCT had a statistically significant impact on the frequency of the RMC. Since the present study revealed a frequency of RMCs amounting to 16.12% (corresponding approximately to every sixth retromolar area), we recommend to spare it during surgery or to consider an additional locoregional anesthesia in the retromolar region. For preoperative diagnosis the CBCT has proved suitable, offering the possibility to select the spatial resolution depending on the indication, so that radiation exposure is reduced without a decrease in validity.

Changes in maxillary molar pulp blood flow during orthodontic intrusion

INTRODUCTION/OBJECTIVE

The aim of this prospective study was to evaluate the effects of maxillary first molar intrusion on pulpal blood flow (PBF) in humans as recorded by laser Doppler flowmetry (LDF).

MATERIALS AND METHODS

Maxillary first molars of 16 participants were divided into two groups. In the study group, 20 teeth in 10 participants were subjected to an intrusive force of 100 g delivered from mini-implants for 6 months. A control group of 6 subjects (12 teeth) received no orthodontic treatment. LDF measurements were recorded at baseline and at 3 days, 3 weeks, 3 months and 6 months during intrusion. Data was analysed using the Wilcoxon Signed Rank and Mann-Whitney U tests, with a level of p < 0.05 considered statistically significant.

RESULTS

No significant changes in PBF perfusion units (PU) were observed in the control group over the course of the study. However, PBF in the study group was significantly higher at TO (8.7 ± 0.9 PU) when compared with T1 (6.1 ± 0.6 PU, p < 0.001) and T2 (6.0 ± 0.6 PU, p < 0.001). PBF did not vary significantly between T1 and T2 (p = 0.073) or between T3 and T4 (p = 0.262). Moreover, PBF at the end of the study (T4) was similar to baseline PBF values for both groups (study group: p = 0.687; control group: p = 0.525).

CONCLUSIONS

Despite significant short-term regressive changes in pulpal tissue during continuous molar intrusion with mini-implants and an applied force of 100 g, blood vessel function was maintained throughout intrusion, as indicated by LDF measurements of PBF, which tended to return to baseline values by the end of the observation period. These results highlight the changes that can occur in molar vascularity, especially during six months of intrusion.

Pediatric intraoral high-flow arteriovenous malformation: a diagnostic challenge

Arteriovenous malformations (AVMs) are rarely reported in the dental pediatric literature. They may develop adjacent to primary molars and can be life-threatening due to their potential for massive bleeding. The most common symptom associated with documented cases of AVMs is spontaneous gingival bleeding. Other clinical signs include pain, erythematous gingiva, resorption and mobility of teeth, soft tissue discoloration, facial swelling, and asymmetry. Radiographically, AVMs are osteolytic lesions. The purpose of this report was to describe the challenge of diagnosis of a high-flow arteriovenous malformation located in the primary maxillary molar region, which was misdiagnosed as a dentoalveolar abscess adjacent to previously treated primary molars. A decision to extract a tooth with gingival swelling and associated spontaneous bleeding should be made after the differential diagnosis of a vascular malformation has been ruled out.

Retromolar foramen and canal: a comprehensive review on its anatomy and clinical applications

The retromolar foramen (RMF) and retromolar canal (RMC) are the anatomical structures of the mandible located in retromolar fossa behind the third molar tooth. This foramen and canal contain neurovascular structures which provide accessory/additional innervation to the mandibular molars and the buccal area. These neurovascular contents of the canal gain more importance in medical and dental practice, because these elements are vulnerable to damage during placement of osteointegrated implants, endodontic treatment and sagittal split osteotomy surgeries and a detailed knowledge of this anatomical variation would be vital in understanding failed inferior alveolar nerve blockage, spread of infection and also metastasis. Although few studies have been conducted in the past showing the incidence and types in different population groups, a lacunae in comprehensive review of this structure is lacking. Though this variation posed challenging situations for the practicing surgeons, it has been quite neglected and the incidence of it is not well presented in all the textbooks. Hence, we made an attempt to provide a consolidated review regarding variations and clinical applications of the RMF and RMC.

Pulpal cellular reactions to experimental tooth movement in rats

OBJECTIVE

The objective was to study the early cellular reactions of the dental pulp during experimental tooth movement.

STUDY DESIGN

A total number of 98 male rats were used. Tooth movement was induced for 1 to 168 hours by inserting elastic bands between maxillary first and second molars of animals, which were labeled with tritiated thymidine. Pathologic signs, macrophage content, and proliferation of fibroblasts and endothelial cells were assessed histologically on autoradiographs of second molar pulps. Data were analyzed using ANOVA with Tukey's test as post hoc pairwise comparison.

RESULTS

Pathologic signs and macrophage content generally increased with time after the induction of tooth movement. The proliferation of pulpal connective tissue progenitor cells and endothelial cells increased as a reaction to the force application.

CONCLUSIONS

Force-induced tooth movement may lead to extensive, however temporary, trauma of the pulpal tissues, which react with early wound-healing events, such as macrophage invasion, cell proliferation, and angiogenesis.

Arteriovenous malformation of the mandible: a case report

Arteriovenous malformations (AVMs) are an abnormal collection of blood vessels. They are extremely rare congenital or acquired abnormalities in the structure of blood vessels. These malformations have been associated with severe hemorrhage resulting in significant morbidity and mortality. Gingival bleeding seems to be a common symptom of most documented cases of AVM, and radiographs most often appear normal. A 12-year-old girl who was first examined by a general dentist for occasional bleeding associated with the right mandibular teeth was referred to the University of Istanbul, Faculty of Dentistry. During the suturing process to stop the leakage around the mandibular right first molar, uncontrollable hemorrhage began. Magnetic resonance imaging and angiogram revealed the AVM of the right mandibular body. After embolization with an injection of a mixture of cyanoacrylate and lipiodol, the tooth was extracted and initial periodontal therapy performed. The patient has maintained a satisfactory gingival and oral condition since the completion of dental treatment and establishment of oral hygiene. Clinicians should be aware of these lesions and the impact they can have on routine procedures. Proper recognition and therapeutic intervention can help to avoid serious complications and potentially tragic outcomes.

Morphologic and hemodynamic analysis of dental pulp in dogs after molar intrusion with the skeletal anchorage system

INTRODUCTION

We have successfully treated skeletal open bite by intruding posterior teeth with the skeletal anchorage system. Our aim in this study was to morphologically and hemodynamically evaluate the changes in pulp tissues when molars are radically intruded.

METHODS

The mandibular fourth premolars of 9 adult beagle dogs were divided into 3 groups: a sham operated group (n = 6, 3 dogs), 4-month intrusion group (n = 6, 3 dogs), and a further 4-month retention group (n = 6, 3 dogs). We evaluated the morphological changes of the pulp and dentin-the amount of vacuolar degeneration in the odontoblast layer, the predentin width and nervous continuity in the pulp tissue, and the pulpal blood-flow response evoked by electrical stimulation in the dental pulp.

RESULTS

Extreme molar intrusion with the skeletal anchorage system caused slight degenerative changes in the pulp tissue, followed by recovery after the orthodontic force was released. Circulatory system and nervous functions were basically maintained during the intrusion, although a certain level of downregulation was observed. These morphologic and functional regressive changes in the pulp tissue after molar intrusion improved during the retention period.

CONCLUSIONS

Histologic changes and changes in pulpal blood flow and function are reversible, even during radical intrusion of molars.

The blood vessel system in the periodontal ligament of the equine cheek teeth--part I: The spatial arrangement in layers

Corrosion casts of blood vessels in the periodontium of cheek teeth from eight horses were observed three-dimensionally with a dissection microscope. Selected specimens were examined in a scanning electron microscope. Periodontal blood vessels communicated with those from the gingiva, the alveolar bone, and the apical region. In the upper jaw, there were anastomoses with the blood vessels of the mucosa of the maxillary sinus. The periodontal vascular system was organized in two or three layers. The peripheral layer was mainly composed of large venules, the inner one consisted of capillaries. In the intermediate layer, blood vessels were post-capillary venules. This layer was developed only in horses under 10 years of age. In all layers the vascular orientation was mainly occluso-apical, this was defined as the standard pattern. There were many variations displayed in different courses of certain blood vessels. The vascular organization is discussed with regard to the specialized functions of the periodontal ligament (PDL). The wide vessels of the outer layer are thought to play a mechanical role as part of a shock absorbing system. The capillaries of the inner layer meet nutritional requirements. The disappearance of the intermediate layer in horses older than 10 years is taken as an adaptation to the remodelling of the PDL. Modifications in the standard pattern of vascular arrangements are also interpreted as adaptations to life-long changes in the periodontal space. Anastomoses between the periodontal vasculature and the blood vessels of the maxillary sinus indicate that periodontal disease may be transferred into the sinus.

Lingual perimandibular vessels associated with life-threatening bleeding: an anatomic study

PURPOSE

To describe the anatomy of the lingual perimandibular vessels and emphasize the distance to the bone.

MATERIALS AND METHODS

The hemifacial lower third was dissected in 12 human cadavers. The blood vessels in the floor of the mouth were exposed using sagittal incisions at the canine, mental foramen, and second molar areas.

RESULTS

The diameter of the dissected vessels ranged from 0.5 to 3 mm (mean, 1.5 mm). Most vessels were found superior to the mylohyoid muscle in the canine area and beneath the muscle in the mental and second molar areas. The smallest median vertical distance from blood vessel to bone was in the canine area (14.5 mm), followed by the mental foramen area (15.5 mm) and the second premolar area (19 mm). The median horizontal distance of the vessels from the lingual plate was 2 mm at the canine and second molar areas and 4 mm at the mental area.

DISCUSSION

Lingual plate perforation, especially anterior to the canine area, can easily injure blood vessels in the floor of the mouth and cause life-threatening hemorrhage following implant placement. Bleeding can occur when the mandibular lingual plate is perforated. Care should be taken to recognize situations where this complication may occur.

CONCLUSIONS

Based on the study of human cadavers, it appears that vessels in the floor of the mouth are sometimes in close proximity to the site of implant placement. Caution should be exercised when placing implants in this area.

Rare courses of the mandibular canal in the molar regions of the human mandible: a cadaveric study

The inferior alveolar artery, vein and nerve send some branches to the molar teeth via the mandibular canal to the mental foramen. The present study attempted to define the presence and course of the mandibular canal in the mandible with the alveolar process by macroscopic cadaveric dissection and computerized tomography (CT) in order to provide information that might prevent injuries to vessels and nerves at risk during root canal treatment. We identified the position of the mandibular canal within a 30% ratio of the distance from inferior border of mandible to the apices of the root for 39 out of 131 sides (mesial root of first molar, 20%; distal root of first molar, 22.6%; mesial root of second molar, 27.8% and distal root of second molar, 47%) on panoramic X-ray observation. In one cadaver (male, 64 years old), the root apex of the second molar was in close proximity to the upper bony mandibular canal. Macroscopic dissection and computerized tomography showed that the main trunks of the inferior alveolar artery, vein, and nerve were in tight contact with the apex of the second molar. These observations of the anatomic course of the mandibular canal will be important to consider during root canal treatment of mandibular teeth.

Initial changes in pulpal microvasculature during orthodontic tooth movement: a stereological study

Any alteration in blood flow or vascular pressure caused by a trauma may damage the pulp tissue. The aim of this study was to evaluate the vascular changes during the initial period of tooth movement. These alterations were assessed in coronal molar pulp tissue of 20 male Wistar rats, 90 days of age, submitted to mesial inclination movement by a closed coil spring, placed from the right maxillary first molar to the maxillary incisors. The animals were divided into three experimental groups of 6, 24, and 72 hours of 0.4 N force application, with five animals in each group, and a control group of five animals without tooth movement. The volume density of blood vessels (V(v)) of the coronal pulp tissue in the experimental groups was calculated by stereology and compared with the control group. The results demonstrated a significant increase in V(v) at 6 hours of 10.2 per cent compared with 7.2 per cent for the control group (P <or= 0.05). At 24 and 72 hours, V(v) was reduced, with values close to those observed for the control group (P > 0.05). These results demonstrate the high capacity of adaptation of the pulp tissue to an aggression, provided the biological limits of tolerance of the pulp are respected.

Vascular status in human primary and permanent teeth in health and disease

The present study sought to compare the vascular status of human primary teeth with that of human permanent teeth, and to determine whether caries or painful pulpitis was associated with changes in vascularity. Coronal pulps were removed from 62 primary and 62 permanent mandibular molars with a known pain history. Teeth were categorized as intact, moderately carious or grossly carious. Pulp sections were labelled with Ulex europaeus I lectin (UEIL), which is a marker of human vascular endothelium. Image analysis was then used to quantify the percentage area of UEIL-labelled tissue (vascularity) and the number of blood vessels present within three regions: the pulp horn, the subodontoblastic region, and the mid-coronal pulp. Only the mid-coronal region of the primary tooth pulp was found to be significantly more vascular than the corresponding area of the permanent tooth pulp. Both dentitions showed a significant increase in vascularity within the pulp horn region with caries progression, but this was not accompanied by an increase in vessel number. There was no correlation between vascularity and pain symptoms. These findings suggest that the primary tooth pulp is more vascular than its successor within the mid-coronal region. However, the functional and clinical significance of this finding remains speculative.

Mandibular lesions of vasoocclusive origin in sickle cell hemoglobinopathy

Sickle cell hemoglobinopathy is an inherited disorder characterized by vasoocclusive crises. Involvement of the maxillofacial skeleton leading to radiopaque lesions that correspond to bone infarcts has rarely been reported in the literature. Forty-two adult patients suffering from sickle cell anemia were examined radiographically for radiopaque lesions situated in the course of a known vessel or in the apical region of the teeth. In 6 cases, such lesions were combined with facial pain during sickle cell crisis and absence of dental pathology and were considered to be of possible vasoocclusive origin. In conclusion, vasoocclusive involvement should be taken into consideration when assessing painful episodes or neurological symptoms in the maxillofacial region in this patient population.

Effect of nitric oxide on the recovery of the hypofunctional periodontal ligament

The relationship between occlusal stimuli and a hypofunctional periodontal ligament (PDL) structure has been reported, though changes in occlusal recovery conditions were still unclear. Nitric oxide (NO) produced by NO synthase (NOS) is considered a factor for vascular and immune system control, and it increases according to mechanical stimuli. The objective of this study was to examine the relationship between NOS and occlusal stimuli in PDL by comparing hypofunction with occlusal recovery. The study focused on the expression of endothelial NOS (eNOS) and inducible NOS (iNOS). Their expression significantly decreased in occlusal hypofunction compared with the control group and increased close to normal in an occlusal recovery group. The change in the immunopositive area was more dramatic than the immunopositive cell number. Moreover, the rate of iNOS increase was higher than that of eNOS. This study suggests that NO plays an important role in the recovery of the hypofunctional PDL.

Pulpal blood flow: effects of corticotomy and midline osteotomy in surgically assisted rapid palatal expansion

INTRODUCTION/PURPOSE

Surgically assisted rapid palatal expansion is used for the management of transverse maxillary deficiency in the early permanent dentition. The success depends on the maintenance of an adequate blood supply to the mobilized segments. The aim of this study was to assess the effects of corticotomy and midline osteotomy on the tooth pulpal blood flow.

MATERIAL

Laser Doppler flowmetry was applied as a non-invasive and reliable technique for the assessment of pulpal blood flow in the maxillary centrals, canines and first molars. The blood flow was investigated pre- and postoperatively, on the first, third, and seventh postoperative days bilaterally in 13 cases.

RESULTS

The results of this study indicate that ischaemia of the pulp can occur following osteotomy at the Le Fort I level.

CONCLUSION

Corticotomy 5mm above the dental apices and separating the midpalatal suture did not have any serious effect on pulpal blood flow in this study.

The triangle of safety: a modified posterior superior alveolar injection technique based on the anatomy of the PSA artery

The posterior superior alveolar (PSA) injection technique is commonly used to anesthetize soft and hard tissues of the posterior maxilla. As with all injections, complications arise, including hematoma formation secondary to needle-induced vascular trauma. In an attempt to develop a hemorrhage-free PSA injection technique, 361 infratemporal dissections were completed on human cadaver specimens. Three distribution patterns were identified for the external branch of the PSA artery. Regardless of distribution pattern, an anatomical Triangle of Safety was found superior to the maxillary second molar that was free of neurovascular tissues in more than 99% of individuals. Injection into this area appears to meet anesthetic needs while reducing the risk of hematoma formation. The combination of this anatomical triangle with newer anesthetic agents and computerized delivery systems holds promise for continued improvement of the PSA injection technique.

Ultrastructural changes in postcapillary-sized venule morphology in aged mouse periodontal ligament

The aim of this study was to compare the postcapillary-sized venule (PCV) morphology of four young ALCA mice (35 days) and four colony-related aged mice (365 days) using the transmission electron microscope (TEM). Right and left mandibular first molar mesial roots with associated periodontal ligament (PDL) and bony socket, were used for TEM assessment. Five PCV profiles were selected at each 160 microm interval, from the alveolar crest to the tooth apex. PCV profile dimensions were measured on standardised micrographs magnified x2900. Age affects were tested using multiple regression analysis. The number of PCV profiles in the tooth third of the PDL was higher in aged mice (p < 0.01) and comprised predominantly apericytic vessels (p < 0.001). The number of PCV profiles increased significantly (p < 0.001) in aged mice in the PDL middle circumferential third halfway down the molar root. Age had no significant affect on PCV diameter. Aged PDL permeability studies are needed to investigate whether the changes in aged PCV profile number are associated with functional modification of the PDL microvasculature.

Developmental changes of the vasculature in the periodontal ligament of rat molars: a scanning electron microscopic study of microcorrosion casts

Vascularization of the periodontal ligament was examined in developing upper first molars of rats from 5 to 30 d after birth with light and scanning electron microscopy. Formation of the vascular network in the periodontal ligament (PDL) started with the beginning of root formation. The PDL vessels derived from the basal region of the tooth germ ran parallel to the long axis of the root and connected with the vascular network of the enamel organ at the cervical end. The boundary of these 2 networks was initially indistinct but became clearer with the progress of root formation. The PDL vessels further elongated longitudinally and connected with each other by lateral branches to form a coarse mesh. Other vessels derived from the alveolar bone via Volkman's canals also contributed to the vascular construction of the PDL. The vessels from the alveolar bone provided branches to the existing mesh of the PDL. Consequently, the vascular network of the PDL consisted of vessels from 2 sources: 1 derived from the basal region of the tooth germ, and the other from the alveolar bone. The density of the vascular network reduced with the progress of root formation, especially at the middle part of the root, but the mesh at the apical region maintained a basket-like structure.

Development of a method to detect and quantify prostaglandin E2 in pulpal blood from cariously exposed, vital primary molar teeth

AIM

The aim of this in vitro study was to detect and quantify an established marker of inflammation, prostaglandin E2 (PGE2), in blood samples harvested from radicular pulp stumps after coronal pulp amputation.

METHODOLOGY

Harvesting was achieved by a paper strip 'dip-stick' method and the volume of each sample estimated before storage at -80 degrees C. A competitive, plate-based enzyme immunoassay technique (EIA) was developed for detection and quantification of the inflammatory mediator assumed to be present in blood samples. Since this technique had not previously been used to assess pulp blood, steps in the development of harvesting, storage, extraction and validation of this sensitive assay are described.

RESULTS

Thirty-nine single-blood samples were assayed and yielded detectable amounts of PGE2 ranging from 1.0 to 2641 ng mL-1.

CONCLUSIONS

The results of this investigation indicate that the inflammatory mediator, PGE2 can be detected and quantified in small blood samples from pulp stumps. Further development may derive quantitative tests for determining the condition of pulp tissue in primary molar pulp treatment.

Pulpal blood-flow characteristics of maxillary tooth morphotypes as assessed with laser Doppler flowmetry

OBJECTIVE

The purpose of this study was to determine the effect of tooth morphotype on intraindividual and interindividual variations of baseline data as well as on temporal variations between testing intervals in the assessment of pulpal blood-flow by means of laser Doppler flowmetry.

STUDY DESIGN

In 14 volunteers, maxillary incisors, canines, premolars, and first molars were investigated bilaterally by laser Doppler flowmetry to assess local pulpal blood-flow values. Measurements in perfusion units were taken during 3 sessions, with a time interval of 7 days between sessions.

RESULTS

Intraindividual comparisons of tooth morphotype-related pulpal blood-flow values revealed significant differences only for the first molar, whereas significant interindividual differences were found for the lateral incisor, canine, premolars, and first molar. Pulpal blood-flow values for the second premolar (11.1 perfusion units) were significantly higher and those for the central incisor (7.6 perfusion units) significantly lower than those for the lateral incisor (9.2 perfusion units) and first molar (9.4 perfusion units). In contrast, measurements at the lateral incisor, first premolar, and first molar did not differ significantly (P > .05). Multiple testing showed no statistically significant effect on tooth morphotype-related pulpal blood-flow measurements.

CONCLUSIONS

The findings indicate that contralateral incisors, canines, and premolars are appropriate intraindividual controls for local pulpal blood-flow recordings. Other studies may identify the effect of environmental and technique-related factors on the assessment of local pulpal blood-flow values.

Arterial supply of the maxillary teeth in the crab-eating monkey (Macaca fascicularis)

Superior dental rami diverging from arterial multi-resources of the crab-eating monkey were investigated by means of plastic corrosion castings. Correlations between the dental ramus/rami entering the apical foramen/foramina of each maxillary tooth were elucidated. Superior dental rami supplying the maxillary teeth diverged from the posterior superior alveolar, infraorbital, descending palatine, major palatine and sphenopalatine arteries as follows: The posterior superior alveolar gave rise to molar branches which supplied three molars and rarely an additional two premolars, to premolar branches and to a canine branch as its terminus. The infraorbital gave off canine branches. The descending palatine gave rise to a molar branch which supplied the lingual root of each molar. The major palatine gave rise to a premolar branch which supplied the lingual roots of two premolars and the 1st molar, and an incisive branch which supplied two incisors. The sphenopalatine supplied the lingual root of each molar and rarely the 1st premolar in addition. Two incisors were supplied by the major palatine (100%), the canine by the posterior superior alveolar (50%), this artery and the infraorbital (43.3%) or the infraorbital only (6.7%). Three roots of each premolar were supplied by the posterior superior alveolar, occasionally the lingual root (16.7%) and mesiobuccal root (3.3%) of the 1st premolar by the major palatine, the lingual root of the 2nd premolar by the major palatine (6.7%) and the sphenopalatine (3.3%). Two buccal roots of each molar were also supplied by the posterior superior alveolar (100%), occasionally the lingual root of the 1st molar by the descending palatine (6.7%), the major palatine (6.7%) or the sphenopalatine (3.3%), the lingual root of the 2nd molar by the descending palatine (30%), the sphenopalatine (10.0%) or the infraorbital (3.3%), the lingual root of the 3rd molar by the descending palatine (23.3%), the sphenopalatine (20.0%) or the infraorbital (3.3%). Superior dental rami diverging from the posterior superior alveolar artery were distributed to the molars, premolars and canine as principal arterial vessels of the crab-eating monkey. The descending palatine, sphenopalatine and the infraorbital arteries were supplementary to the above main arteries. Two incisors were only supplied by the major palatine but the anterior and middle superior alveolar were not observed.

Three-dimensional observations of accessory canals in mature and developing rat molar teeth

The structure, distribution and formation of accessory canals in the developing and mature molar teeth of rat mandibular jaws were investigated with scanning electron microscopy and with three-dimensional image analysis using serial light-microscopic sections. In the initial stage of the accessory canal formation, most of the canals appeared in the gaps of the epithelial root sheaths formed by their approaching each other in the initial stage of the root formation. However, some of the canals appeared in the slits which may be formed by the destruction of the epithelial root sheath in the root apex regions. When the gaps and slits were invaded by blood vessels, the regions surrounding the vessels did not mineralize but became accessory canals. Usually, an accessory canal with one blood vessel connected the periodontal ligament to the dental pulp; however, in some cases, the canals were broken off midway following the destruction of the vessels.

Vascular pathways within pulpal tissue of human primary teeth

The vascular distribution within pulps of human primary teeth has not been as well studied as those within human permanent teeth. Such information is useful to those who diagnose and treat dental conditions in children. The purpose of this study was to determine the architecture of the vascular structures, in contrast to the histological appearances, of noncarious human primary teeth during root completion, root resorption and dental caries attack. Following extraction, primary teeth were perfused with an opaque injection mass and photographed to trace the courses of the arterioles, venules and capillaries within the crowns and roots. The architectural morphology of similar vascular structures in permanent pulps are included to provide a comparative reference. Arterioles entered the apical foramina and traveled throughout the root canal(s) to the pulpal chamber, giving off branches which passed toward the dentinal walls. Within the pulpal chamber, the arterioles passed toward the occlusal and proximal surfaces and arborized profusely to form a subodontoblastic plexus of capillaries. The capillaries lead to larger diameter venules, which exited the pulp through apical foramina. Many unusual vascular pathways existed within the root structure. No communication existed between the pulp chamber and periodontal membrane through the furcation dentin and cementum. Many lateral canals were seen along the root structures.

Resorption of the crown of an unerupted permanent molar

This case report describes an unusual phenomenon where resorption occurred in the crown of an unerupted permanent molar. It was an incidental radiological finding. After eruption the tooth was extracted. Histological examination revealed resorption of enamel and dentine, and partial replacement by calcific material. The possible aetiology of the condition is discussed.

Mandibular and molar vascularization in guinea pigs. Scanning electron microscopic study of corrosion casts

The vascularization of the mandible, molar teeth, and periodontal ligament of adult male and female albino guinea pigs (Cavia porcellus) was studied by scanning electron microscopy of vascular corrosion casts. Main routes of mandibular blood supply and drainage are shown, and the intrinsic vascular patterns of the mandible, the molars, and the periodontal ligament are described. Results are compared to findings in man and in other mammals.

Ultrastructure of the venous ampulla in the interradicular microvascular bed of the mandibular molars of Mus musculus

The interradicular periodontal ligament of mandibular molars contains an apparently unique dilated vessel straddling the interradicular alveolar bone. This structure is designated a venous ampulla. The vessel possesses a luminal length and width of approximately 200 X 100 microns, respectively. Ultrastructurally, the endothelium has an average thickness of 0.35 micron, a continuous basement membrane, and an incomplete layer of pericytes. Open endothelial junctions are not present. The anatomy of the vessel wall differs markedly on the dental- and bone-related aspects. Calculated ratios for the luminal diameter to wall thickness vary from 1:80 to 1:150. Postcapillary-sized limbs from this vessel drain into the interradicular septum of bone and the ligament microvascular bed. Arterial supply to the ampulla is provided via arteriovenous anastomoses characterized by their association with myelinated and unmyelinated nerve groups. Oxytalan fibers are present throughout the wall of the venous ampulla, penetrating to the abluminal side of the endothelium where they are associated with unmyelinated axons and free nerve endings. Elsewhere, oxytalan fibers are related to the arteriovenous anastomoses and their accompanying myelinated and unmyelinated nerves located adjacent to the endothelium. Pericytes form membranous contacts with the endothelium of the arteriovenous anastomoses and have processes penetrating the endothelium basement membrane.

A scanning electron-microscopic, stereo-pair study of methacrylate corrosion casts of the mouse palatal and molar periodontal microvasculature

Microvascular beds of the palate, gingiva and periodontal ligament had interconnected but distinct, regional patterns. The palatal vasculature reflected mucosal-crest morphology: crestal capillary vessels of the rugae anastomosed with sagitally-orientated rows of 8 microns capillary loops, and, in the inter-rugal troughs, these formed a flat plexus overlying collecting veins more than 100 microns in diameter. Maxillary and mandibular molar ligaments had similar microvascular patterns. The molar gingiva had a circular, outer capillary and inner venous system linked by radial anastomoses. The outer (7 microns) capillaries enclosed the three molars in a continuous horizontal loop coursing beneath the crestal epithelium; the inner (10-15 microns) venous vessels encircled each molar just below the epithelial attachment. Glomerulus-like vascular formations, with an arterial and venous stalk, were associated with the inner circular system and extended toward the crevicular epithelium. Axially aligned, post-capillary, periodontal-ligament vessels (21 microns) anastomosed with the inner circular system, forming different patterns in the occlusal, middle and apical thirds. The apical pattern comprised an enveloping plexus of anastomosing venous vessels supplied by arterio-venous shunts; similar shunts were present throughout the ligament. The microvascular bed of the mandibular inter-radicular ligament was characterized by the presence of a large venous ampulla measuring 60 by 200 microns. Some regions of the ligament microvasculature drained via the medullary vessels into 50 microns-diameter venules located interdentally deep to the molar apices. Volumetrically, the ligament microvascular bed was predominantly of post-capillary venules, and morphologically, a paired arterial and venous system was not demonstrated.

[Functional anatomy of the blood vessels of the dental pulp in the white rat]

Applying a complex of modern microangiological techniques, the organization of the blood bed in the incisor and molar pulp has been studied in the white rat mandible. Production of the dental tissue components in the zones of dentinogenesis is ensured by an increased density of the capillary and venular bed of the pulp, a tight connection of the capillaries with predentin. The morphometric data obtained make it possible to prognosticate a high intracapillary pressure and the hydratation degree of the interstitial gel in the incisor pulp, which is close to maximal figures. Differences in angio-architectonics of the incisor pulp and the molar pulp depend on the peculiarities of the histostructure and functional state of the pulp, on the geometry of the dental cavity and the radicular canals. The pulp blood bed possesses a complex apparatus that ensures the blood stream regulation (duplication of the nutrition sources, arteriolar and venular area, various types of anastomoses, precapillary sphincters and others).

The vascular pattern in the papillary region of rat incisor and molar tooth enamel organ

Scanning electron microscopy of the enamel organ of rat incisor and molar teeth in the maturation stage of amelogenesis revealed two vascularization patterns of the papillary layer. In one pattern, the anastomosing capillaries formed loops of varying sizes around spherical or somehwat oblong papillae. In the second pattern, the capillaries were parallel to each other embedded in furrows between long ridges of papillary cells. It is postulated that each of these two patterns may be associated with a specific stage in the process of enamel maturation.

[Comparative studies of the mirocirculation in the cement organ of the teeth of rats. Part 3: Cement organ (author's transl)]

The author deals with the blood supply of the cement organ in rat incisors and molars. In both tooth types the microcirculatory structure is similar. The arteria and accompanying capillaries supplying the cement organ run parallel to each other and the root. The similar organization of blood supply in the two tooth types is attributed by the author to developmental and functional causes.

Quantification of pulpal blood flow in developing teeth of dogs

Pulpal blood flow was determined in 32 dogs ranging in age from 6 weeks to 18 months by the isotope fractionation method incorporating diffusible and nondiffusible tracers. Dogs were placed into selected age groups by the developmental status of the canine teeth. For the teeth sampled, the maxillary first, second, and third incisors along with the canines and first molars, pulpal blood flow was determined to be not different in teeth at various developmental stages. For some dental pulps, alveolar mucosa, and bone, the tracers were not determining equivalent blood flows. Because of incomplete trapping of the 7- to 10 mu microspheres and the flow limitation of 86Rb, the 15 mu spheres would appear to be a reliable indicator of "total" blood flow to pulpal tissues. However, in alveolar mucosa and bone, and 15 mu microspheres may not be completely trapped and thus, may underestimate blood flow to these tissues. Within the age range of these dogs, tissue blood flow was not dependent upon the stages of oral development.

Vascularization of the periodontal tissues in the adult laboratory rat

A study was undertaken to find a standard method that would be relatively reproducible and would visualize the vascular changes in hard and soft tissues that accompany pathologic changes. Each tooth and its surroundings were found to have a complex vascular network that is directed to its particular function. Also each network is closely connected with other vascular networks; they form a complex blood supply source which, when necessary, can easily provide a compensatory blood supply.

Vascular and nerve supply to the molar teeth of guinea pigs

SYNOPSIS IN INTERLINGUA

PROVISION VASCULAR E NEURAL DEL DENTES MOLAR DE PORCOS DE INDIA.—PORCOS de India de varie etates esseva usate pro studiar le provision vascular e neural del dentes molar. Le vasos sanguinee esseva demonstrate per le methodo a perfusion de tinta de China e gelatina, durante que le nervos esseva demonstrate per le methodo de Pearson a gelatina argentee. In le tertio apical del dentes, le vasos sanguinee se trovava in adjacentia al predentina, durante que in le tertio occlusal, le vasos se trovava exclusivemente in le pulpa in senso restringite. Le vasos sanguinee esseva incontrate in adjacentia al ameloblastos. Nonmedullate fibras associate con vasos de sanguine esseva trovate in le pulpa. Libere terminos neural e incapsulate structuras fusiforme esseva incontrate in le ligamento periodontal.