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At least 1,063 records · Page 59Linked to original sources
PubMed2001

A clinical and histological evaluation of titanium mini-implants as anchors for orthodontic intrusion in the beagle dog.

The aim of this study was to determine the anchorage potential of the titanium mini-implant for orthodontic intrusion of the mandibular posterior teeth. Six mini-implants were surgically placed around the mandibular third premolars on each side in 3 adult male beagle dogs. On the buccal site, three mini-implants were placed distal to the apex of the distal root of the third premolar, at the interradicular septa of the third premolar, and mesial to the apex of the mesial root of the third premolar, as linearly as possible. The same procedure was performed at the lingual site on both sides of the mandibular third premolars in each dog. Bilateral interradicular mini-implants on both the buccal and the lingual sites were used as the anchorage for the intrusion of the third premolars (loaded implants) and the other mini-implants were used as control (unloaded) implants. In 6 weeks, an intrusive force (150 g) was applied between the interradicular implants on the buccal and the lingual sites by closed coil springs run across the crowns of the third premolars. After 12 to 18 weeks of orthodontic intrusion, the animals were killed and their mandibles were dissected and prepared for histologic and fluorescent observation. The results indicated that the mandibular third premolars intruded 4.5 mm, on average, after 12 to 18 weeks of orthodontic force application, with mild root resorption at the furcation area as well as the root apex. All the mini-implants remained stable during orthodontic tooth movement without any mobility or displacement. The morphometrical findings indicated that the calcification of the peri-implant bone on the loaded implants was equal to or slightly greater than those of the controls. In addition, 6 of the 36 mini-implants were removed after tooth movement, and all of them were easily removed with a screwdriver. These findings suggest that mini-implants are effective tools for the anchorage of orthodontic intrusion in beagle dogs.

Alveolar Process↗
PubMed1991

Dilaceration of a primary tooth.

A case is presented in which a non-vital maxillary primary incisor failed to resorb, its root apex appeared in the labial sulcus and further investigation showed it to be dilacerated.

Child↗
PubMed2004

The accuracy of the cementoenamel junction identification on periapical films.

In the study of orthodontically induced inflammatory root resorption, many researchers use the cementoenamel junction (CEJ) as a bisecting reference point to measure the amount of root shortening. The accuracy of the identification of the CEJ point might affect the conclusions of those studies. This study aims to find the effects of angular changes between the tooth and the film on the validity and reproducibility of identifying three different CEJ points, ie, the most apical CEJ point between the crown and the root, the most mesial CEJ point, and the most distal CEJ point. An extracted maxillary central incisor was placed in a special jig and radiographed at four different tooth to film angulations. Eight examiners were asked to identify the buccal and palatal CEJ, whereas six examiners were asked to identify the mesial and distal CEJ points, all on a computer monitor. The distances between the identified points and the apex were computed and compared with the actual ones. The angular changes between the tooth and the film did have a statistically significant effect on the identification of some of these CEJ points. The difference was significant on the identification of the buccal and palatal points but not on the mesial and the distal ones.

Analysis of Variance↗
PubMed1992

Histomorphometric study of the periodontal vasculature of the rat incisor.

This study assessed quantitatively the vascular system in the cementum-related periodontal ligament (PDL) along the rat incisor. The lower left incisors of six rats (+/- 200 g) were subjected to routine histological procedures and cross-sectioned serially (2 microns), and the distance between each section and the apex was computed. The PDL of five sections at different levels along the tooth was divided into mesial, lingual, and lateral parts. The number and area of small and terminal arterioles, capillaries (C), sinusoids (S), post-capillary venules (PCV), and connecting venules, as well as the area of the PDL, were established. Blood vessels (BV) occupied 47 +/- 2% of the PDL area in the apical half and 4 +/- 2% at the incisal end. Of the total BV area, 41%, 32%, and 27% were located on the lingual, mesial, and lateral tooth sides, respectively. The majority of BV belonged to the venous system (98.5 +/- 0.6% and 82.5 +/- 3.0% in the apical and incisal parts, respectively). The apical venous system comprised 95.4 +/- 1.6% S and 3.2 +/- 1.0% PCV, reversing to 27.2 +/- 14.2% S and 55.2 +/- 11.3% PCV in the incisal half. The number of arterial profiles increased gradually from 6.8 +/- 1.5 at the apex to 25.3 +/- 2.4 in the incisal part and that of C from 9.0 +/- 1.18 to 25.0 +/- 4.3. The extensive vascularization in the apical half of the PDL is consistent with the high metabolic demands and with the need for protective cushioning of the constantly growing dental and periodontal tissues.2+_

Alveolar Process↗
PubMed1990

Central representation of dental structures in the kitten, including projections to the mesencephalic trigeminal nucleus.

Horseradish peroxidase (HRP) was injected into either a single maxillary or a single mandibular primary (deciduous) cuspid tooth of 8- to 10-week-old kittens. The large apex of the primary cuspid allowed for some leakage of the HRP from the pulpal chamber to the periodontal ligament (PDL). Thus, the injection procedure resulted in the application of HRP to the PDL as well as to the pulpal tissues. The transganglionic transport of HRP resulted in discrete terminal fields within the spinal trigeminal nucleus (STN) and the main sensory nucleus (MSN). These projections were clearly somatotopically organized within the STN, but less so within MSN. Within pars oralis (PO) and pars interpolaris (PI), mandibular cuspid dental structures (MdCDS) were represented in a dorsal position relative to the maxillary cuspid dental structures (MxCDS), whereas within pars caudalis (PC) and the adjacent reticular formation the somatotopic representation was not dorsoventral, but rather mediolateral, with the MdCDS represented more medially than the MxCDS. Areas of overlap between MxCDS and MdCDS were found within MSN and to a lesser degree within the superficial laminae of PC. In addition, the fiber pathway leading to labeled somata in the mesencephalic trigeminal (Mes V) nucleus was clearly identified. The majority of the fibers traced to the Mes V nucleus exited the spinal trigeminal tract at the level of the transition from PO to the MSN and traversed the nuclear region in a position dorsal to and separate from the trigeminal motor tract. As in STN, fibers within the caudal Mes V tract appeared to be somatotopically organized, with the fibers from the MdCDS generally more dorsal than the ones from the MxCDS. Labeled fibers, some with terminal arbors, were also identified in close association with the trigeminal motor tract. The findings show a complex pattern of central representation in the immature feline central nervous system for deciduous dental structures.

Afferent Pathways↗
PubMed1980

Dental trauma. Report of a case.

A case of intrusive luxation with accompanying root fracture of a deciduous upper left lateral incisor is described. In this case the separated root apex partly penetrated into and become fused with the permanent successor tooth.

Child↗
PubMed1990

Influence of the major and minor foramen diameters on apical electronic probe measurements.

There have been conflicting reports on the accuracy of electronic devices used for determining working length. The influence of the major and minor diameters on electronic probe measurements were evaluated to ascertain whether anatomical features of the apical portion of the canal might be responsible for these discrepancies. Forty-seven nonrestorable teeth selected from 22 patients were studied. Conventional access was made. A Kerr file was placed to a position 0.5 mm from the major foramen as registered by the Neosono-D apex locator. The electronic probe length was then measured. After the tooth was extracted, the file was fixed with autopolymerizing composite in the canal. A Buehler Isomet lapadary saw was used to prepare specimens to a thickness of 500 microns. A Bioquant II Image Analysis System was used to measure and record distances. It was found that as the width of the major foramen increased, the discrepancy between the electronic probe tip length induction and the actual position of the major foramen increased.

Dental Pulp Cavity↗
PubMed1986

Mental foramen and mental nerve: changes with age.

In a study of 525 dry mandibles and dissections in 50 cadavers, the mental foramen (MF) was found: single in 94.67% of the cases and multiple in 5.33%. Its shape was round in 34.48% with an average diameter of 1.68 mm and oval in 65.52% with an average long diameter of 2.37 mm. In 43.66% the MF was located in front of the apex of the root of the second premolar. In children before tooth eruption, the MF is somewhat closer to the alveolar margin; during the eruption period, the MF descends to half way between the margins, and in adults with the teeth preserved, the MF is somewhat closer to the inferior border. With loss of teeth and bone resorption the MF moves upwards closer to the alveolar border. In extreme cases of resorption the MF and the adjacent part of the mandibular canal are open at the alveolar margin. In the dissections the findings were similar. The mental nerve emerged from the MF closer to or at the alveolar border, according to the degree of resorption. In extreme degrees of resorption, the mental nerve and the final part of the inferior alveolar nerve were found directly under the gums. In these cases, the vestibular grooves became very shallow, and the mucosa passed directly from the cheeks over the alveolar ridge. Practical implications of the changes of the MF and mental nerve are discussed.

Adolescent↗
PubMed1993

The sensory innervation of the periodontium of the third premolar in Monodelphis domestica.

Location and structure of sensory nerve endings in the periodontium of the third premolar in Monodelphis domestica have been investigated by means of light and electron microscopy. The periodontal cleft of the tooth is apically enlarged. The number of nerve endings increases towards apex. Three types of sensory nerve endings have been observed: free nerve endings, Ruffini nerve endings and lamellated corpuscles. Free nerve endings could only be identified by electron microscopy. Ruffini nerve endings are only incompletely surrounded by lamellae of the terminal Schwann cell. Protrusions of nerve terminals of the Ruffini corpuscles are anchored between bundles of collagen fibers. Small lamellated corpuscles occur exclusively in the apical portion of the periodontium. Ruffini and lamellated corpuscles are considered as part of a masticatory reflex feedback control system. Ruffini corpuscles detect tension, rapidly adapting lamellated corpuscles detect pressure and vibration in the periodontium. Free nerve endings may function as thermoreceptor or nociceptor.

Animals↗
PubMed1979

Root canal morphology of the maxillary first premolar.

Four hundred maxillary first premolars were decalcified, injected with dye, cleared, and studied. The canal configurations were categorized as: 26% had one canal, 69% had two canals, and 5% had three canals at the apex. The relationship of canal configuration to number of roots per tooth was determined. Of the canals studied, 49.5% had lateral canals. They occured equally in all types of canals, were located mainly in the apical region, and exited from the main canal mostly in a palatal direction. Also, 11% of these canals extended from the floor of the pulp chamber to the furcation area. An accurate knowledge of the morphology of the pulp cavity is essential before endodontic procedure can be approached rationally. The frequency with which root canals unite should be considered during enlargement and filing procedures. The dentist also should be aware of the possible existence of bifurcated and double canals if root canal therapy should unexplainbly fail. A knowledge of these variations will assist the dentist in reaching conclusions when diagnosing and treating endodontic cases.

Bicuspid↗
PubMed1999

Inverted impaction of a mesiodens: a case report.

Dental, radiological, dermatoglyphic and genetic findings of a patient showing inverted impaction of a mesiodens are presented. It is probable that the inversion of the mesiodens was caused by contact of the incisal edge of the crown of the mesiodens by the apex of the root of the erupting right maxillary central incisor tooth.

Adolescent↗
PubMed1987

[Structure and histo-topography of meniscoid structures of the atlanto-occipital and atlanto-axial joints].

Anatomical preparation, Pirogov's saw-cuts and serial histotopographic sections, made across the atlantooccipital and atlantoaxial joints in the sagittal, frontal and horizontal planes in 35 corpses have been used in reconstructing and studying the meniscoid structures in the area of the joints mentioned. The meniscoids are composed of fine fibrillar connective tissue with a large amount of fat and vessels. The meniscoid has a triangle form, its base consisting of collagenous fibers, gradually transfers into the articular capsule, and its apex is directed into the articular cavity. The meniscoid, surrounding the tooth of the axial vertebra, at the sides passes into the medial parts of the atlantoocipital and lateral atlantoaxial joints, forming a single meniscoid complex of the joints studied. A tight connection is stated between the meniscoids and the perineural formations of the I and II cervical nerves and with the vertebral vessels.

Adult↗
PubMed1988

Relationship of mandibular anterior tooth apices to genial muscle attachments.

Ten adult midsagittally sectioned cadaver heads were used to measure the distance between the apex of the central incisor or canine teeth and the attachment of the genioglossus or geniohyoid muscles. Measurements were made on both cadaver specimens and radiographs. The results of the two methods showed no statistically significant difference. The results indicate that there is a relatively small chance (5.6%) of including the genioglossus attachment in the lingual pedicle if an anterior mandibular subapical osteotomy is positioned 3 to 5 mm below the incisor apex but a large chance (65%) of including the genioglossus muscle when the osteotomy procedure includes the canine teeth.

Adult↗
PubMed1995

Brief communication: Tigaran (Point Hope, Alaska) tooth drilling.

In a sample of 48 adult Tigarans (1300-1700 A.D.) from Point Hope, Alaska, 33 exhibited various degrees of periodontal disease, which, in 25, resulted in tooth loss (Schwartz, unpublished data). Although extreme examples of tooth wear were prevalent in the sample, carious infection was noted in only one individual, in whom the lower central incisors (I1S) had been affected. In the left I1, infection had spread through the root's apex into the alveolar bone, causing an abscess. The buccal (labial) side of the root of this tooth, just below the crown, bears a shallow, relatively flat-bottomed depression, with a small perforation into, as well as a second hole that fully penetrates, the root canal. Both of these features appear to have been produced by an implement, and, as they are associated with a diseased tooth, and ritualistic tooth shaping or drilling of any sort was, and is, not practiced among Arctic groups, their purpose was probably therapeutic. As such, this specimen appears to represent a case of precontact New World Arctic dentistry.

Alaska↗
PubMed1992

The electronic determination of working length.

Electronic digital imaging systems provide the clinician with the ability to manipulate, enhance, and store radiographic images for immediate recall. Apex locators are a useful adjunct to endodontic therapy. It is important to understand that they do not replace radiographs completely in treatment. Radiographs still provide the only means by which the clinician can gain an overall visual image of the tooth being treated. It is important to visualize the crown and root anatomy; the relationship of the crown to the root; the size, shape, curvature, and location of the roots; and to estimate the tooth length. These data give the clinician a good guide and provide a baseline from which to use an apex locator. Failure to do this will result in errors of measurement due to a lack of basic treatment information. The current types of apex locators available are accurate for determining working length, providing some basic steps are followed carefully for their use. Current generation units have degrees of accuracy that range from 83.0% to 93.4%. They need to have well-charged batteries and to be calibrated correctly before use. Resistance-type apex locators require a reasonably dry canal--a guideline that must be strictly followed. Files must be matched to fit the canal snugly, contact against metallic restorations must be avoided, and good lip contact for the return electrode must be obtained. The impedance-type units require careful calibration before use, careful matching of the coated probe to the canal diameter, and good patient contact with the hand-held return electrode. Care must be taken to ensure that the insulating layer does not wear off the coated probes during use. The frequency-based units are easy to use. They operate in an electroconductive environment and have the advantage of using conventional K-type files. However, the rechargeable battery must be kept fully charged, and their calibration steps must be followed. Fluid filling the tooth to the level of the pulp chamber will cause the units to become overloaded, and careful matching of the file to the size of the canal is necessary. Strict adherence to these simple set-up and calibration procedures and the use of the apex locator in conjunction with high-quality, standardized diagnostic radiographs provide the clinician with an accurate and useful adjunct to endodontic therapy.

Dental Pulp Cavity↗
PubMed1993

Reactivated herpes simplex virus infection as a possible cause of dry socket after tooth extraction.

This study was designed to evaluate a possible association between reactivated herpes simplex virus type 1 (HSV-1) infection after lower third molar extraction and development of dry socket (DS). The HSV-1 antibody response was analyzed before and after tooth removal by enzyme-linked immunosorbent assay and immunoblotting in 208 patients. History of previous possible oral herpes reactivation was evaluated by a questionnaire that was based on self-rated frequency of oral cold sores. Tobacco users were identified. The anatomic proximity of the root apex to the mandibular nerve canal was classified radiographically before extraction. Fifteen patients (7%) developed DS after tooth extraction. Eleven of the 15 DS patients (73%) were HSV seropositive as compared with 7 of 15 (47%) in the matched control group. Seven of the 11 seropositive DS patients have shown HSV-1 reactivation by an increase of specific polypeptides, predominantly gB, gC, gD and ICP 4 and 6, in the immunoblot test. No change in HSV-1 reactivity was observed in control sera. DS patients reported a high frequency of oral cold sores (64%) compared with the controls (33%). Tobacco use was not found to influence the frequency of cold sores or the development of DS. A close radiographic proximity between the mandibular canal and root apex was more common (P < .05) in DS patients. The results indicate that extraction of a mandibular third molar could be a possible cause of reactivation and recurrence of an HSV-1 infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗