PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Tooth Apex”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed1976

Streptococcus sanguis: a model in the application in immunochemical analysis for the in situ localization of bacteria in dental plaque.

A review of the development of the serology of S sanguis has been presented. This species contains a group-specific antigen designated a, which appears to be a glycerol teichoic acid. It is suggested that this antigen be designated the Lancefield group H antigen. In addition, two major serotypes based on distribution of other surface antigens have been demonstrated. The grouping antiserums for S sanguis have been used to localize these bacteria in ultrastructural sections of intact dental plaque. The organisms appear antigens and seem to form pyramid-shaped microcolonies with the apex at the tooth surface and the base at the external surface of the plaque. The cells at the apex appear to have lost some surface antigens and seem to be older. The age and arrangement of the cells suggest that most plaque forms by cell division rather than by apposition of new cells from the oral cavity. If this is true, it is necessary to alter some current concepts regarding plaque development and possiby consider some different approaches to plaque control.

Antigens, Bacterial↗
PubMed1997

Periapical repair and apical closure of a pulpless tooth using calcium hydroxide.

A case with a wide-open apex and a large cystlike periapical lesion in an adult is presented. The lesion formed as a result of necrosis from trauma to a maxillary central incisor 12 years ago. After nonsurgical endodontic treatment with calcium hydroxide paste and a calcium hydroxide-containing root canal sealer, apical closure and significant healing of the periapical lesion within 15 months were observed. This report suggests that even large periapical lesions (likely cystic) could respond favorably to nonsurgical treatment.

Adult↗
PubMed1994

A possible explanation for the response characteristics of multi-tooth periodontal ligament mechanoreceptors in the cat.

During the course of a study on the morphology of periodontal ligament mechanoreceptors it was observed that a direct relation, without intervening bone, existed between the mandibular canine and first premolar tooth roots in the cat. An area, representing a window in the alveolar septal bone, extended 2-3 mm from the apex towards the tooth crown. Ruffini nerve terminals were observed amongst the collagen bundles in the ligament between the roots of the two teeth. Light and electron microscopy were used to identify the receptors. It is proposed that a periodontal ligament mechanoreceptor can respond to forces applied to adjacent teeth; movement of both teeth need not occur. This may explain the observation made in the past that single periodontal ligament mechanoreceptors respond to forces applied to more than one tooth.

Alveolar Process↗
PubMed1977

[Tooth regeneration in the guinea pig (Cavia porcellus)].

The first inferior molar has been extracted, a part of its being reimplanted or not. A new molar of normal form regenerated, apparently from the apex of the tooth germ, in all cases in which the alveolus was left free or implanted with a tooth freagment deprived of pulpa.

Animals↗
PubMed1988

The response characteristics of mechanoreceptors related to their position in the cat canine periodontal ligament.

The relation between threshold, adaptation properties and position of these receptors was studied in anaesthetized cats. Electrophysiological recordings were made from functionally single fibres teased from the inferior alveolar nerve as forces were applied to the tip of the left mandibular canine tooth. Receptors were located within the periodontal ligament by paring away the overlying bone. Threshold and adaptation properties were related to the receptor position relative to the fulcrum and apex of the tooth. These results support the hypothesis that there is only one type of periodontal-ligament mechanoreceptor, and that their response characteristics depend on position.

Adaptation, Physiological↗
PubMedDate not supplied

Evaluation of accuracy of an electric device (Neosono D-SE) for the measurement of tooth length.

The study was conducted on 92 root canals selected from teeth advised for extraction to evaluate the efficacy of an electronic device (NEOSONO D-SE), Ingles method and Digital Tactile method for the measurement of working length of tooth. In 30% of anterior teeth and 30% of posterior teeth the electronic device was able to locate exact position of apical constriction of tooth, as measured after the extraction of the tooth. In 37% of anterior teeth and 13% of posterior teeth, the apical constriction was located exactly when digital tactile method was used. When Ingle's method for determining the working length was used it was successful in 30% of anterior teeth and 42% of posterior teeth. The study was also conducted to know the distance between apex of the tooth to apical foramen and distance between apical foramen and apical constriction. The findings of the study showed that the average distance between apex and apical foramen was 0.215mm and 0.289 mm in anterior and posterior teeth respectively. Whereas the distance between apical foramen and apical constriction was 0.610 mm and 0.504 mm in anterior and posterior teeth respectively.

Dental Pulp Cavity↗
PubMed2004

Mechanical stress generated by orthodontic forces on apical root cementum: a finite element model.

OBJECTIVES: 1) To determine the mechanical stress generated at the root apex during different types of tooth movement using a finite element model of an ideal, human maxillary central incisor. 2) To determine the relationship of thickness of cementum and the magnitude of mechanical stress at the root apex. DESIGN: Computer simulation. SETTING AND SAMPLE POPULATION: Not applicable, computer simulation. EXPERIMENTAL VARIABLES: Tooth and investing tissue layers (enamel, dentin, cementum, pulp, periodontal ligament, and alveolar bone). OUTCOME MEASURE: Von Mises and maximum principal stresses. RESULTS: Increasing the apical thickness of cementum increases the amount of mechanical stress. CONCLUSION: A finite element model incorporating all layers of a human maxillary central incisor has been developed. This model was used to determine the location and magnitude of mechanical stress generated for all regions of the tooth, PDL, and enclosed alveolar bone, when orthodontic forces are applied to the tooth. Mechanical stresses were found to increase at the root apex with increasing thickness of apical cementum.

Computer Simulation↗
PubMed1996

Breakage of ultrasonic root-end preparation tips.

Modified ultrasonic tips are used to prepare rootend cavities during endodontic surgery. The purpose of this study was to determine whether such tips are prone to breakage during use. Ten different tip designs were driven by an ultrasonic unit at maximum power. Multirooted teeth were instrumented, the apex removed, and the tooth was placed horizontally on a pan balance. The apex was instrumented by each ultrasonic tip in turn for 15 min, with the load being increased by 100 g every 5 min. Those tips with curvatures of 70 degrees or greater fractured within the first 5-min loading period. Breakage occurred approximately 2 to 3 mm from the end and always at a bend. Scanning electron microscopy revealed that the fractures were brittle in nature, with little change in the remaining section. Two tips bent: one isthmus preparation tip and one silver point removal tip. All the other designs were deemed satisfactory after experimentation. This study shows that fracture of ultrasonic tips can occur and is related to the degree of bending.

Apicoectomy↗
PubMed2005

Surgical endodontics in dogs: a review.

Surgical endodontic therapy (apical surgery) is a treatment alternative aimed at removing periapical inflammatory tissue followed by apical resection and retro-filling of the root canal. These procedures are performed through a trans-osseous approach. Terminology pertinent to this article include: apical (periapical) curettage--a surgical procedure to remove diseased tissue from the alveolar bone in the apical region of a pulpless tooth; apical cyst--a cyst in bone at the apex of a pulpless tooth. It is believed that such cysts arise after the death of the pulp from noxious physical, chemical, or bacterial stimulation of epithelial rests of Malassez; apicoectomy (apical resection) amputation of the apical portion of the root and removal of soft tissue in the bone; epithelial rests of Malassez--cords, strands, or clusters of ectodermal cells in the periodontal ligament (or sometimes alveolar bone) derived from remnants of Hertwigs epithelial root sheath. These cells frequently begin proliferating when inflammation occurs in the periodontal ligament and are believed to be responsible for the genesis of the epithelial lining of apical cysts.

Animals↗
PubMed1990

An in vitro study of the diffusibility of intracanal medicaments.

In this study, the diffusion properties of the vapors of four canal antiseptics were examined. Tricresol, camphore-chlorophenol, Cresophene, and povidone-iodine in clinical doses were tested against Staphylococcus aureus and Streptococcus faecalis. Forty-five extracted human maxillary central incisor teeth were used, and their root canals were prepared. A small amount of antiseptic was placed on a cotton pellet in the pulp chamber of each tooth, and the chamber was sealed with Cavit. Vapors from each of the test medicaments produced zones of inhibition on Staphylococcus aureus and Streptococcus faecalis. The study showed that vapors of the test medicaments do pass through the apex of a tooth and thus have a potential effect at the periapical area. The largest zone of inhibition resulted from the vapor of tricresol.

Diffusion↗
PubMed1984

Evidence for the persistence of axons at the apex of the cat's lower canine tooth after section of the inferior alveolar nerve.

The aim of this investigation was to establish the degree of denervation produced by inferior alveolar nerve section and to provide histological evidence for the presence of pulpal nerve fibres supplying the teeth which do not travel with the inferior alveolar nerve. Four adult cats were used. Each stage of the experiment was carried out under general anesthesia. The left inferior alveolar nerve was exposed and sectioned near the mandibular foramen. After 56 hours and 7 days, respectively, the jaw opening reflex to electrical stimulation of each lower canine was tested. Recordings were made from the left canine during electrical stimulation of the ipsilateral inferior alveolar nerve central and peripheral to the site of section as well as from the ipsilateral and contralateral inferior alveolar nerve during electrical stimulation of the left canine. Recordings were also made from the lingual nerve. After the recordings were completed two animals were perfused 56 hours after inferior alveolar nerve section, two more 7 days after section. Ultrathin sections of the apices of the lower canine teeth were examined in the electron microscope and each nerve fibre photographed. Each axon was examined to determine whether it was degenerating or normal. A jaw-opening reflex could not be elicited by stimulation of the left canine either 2 or 7 days after nerve section, whereas a normal response was evoked by stimulation of the right, control canine. At 2 days small responses could be recorded from the left canine teeth during stimulation of the left inferior alveolar nerve peripheral to the point of section. In one 2-day animal, responses could be recorded in the lingual nerve during stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1980

Selection of allogenic tooth graft using HLA-A, -B, -C and DR typing and the MLC test.

An allotransplantation of a partly developed premolar from a 12-year-old daughter to her mother is reported. The tooth graft was selected by the use of HLA-A, -B, -C and DR typing and the MLC tests. Follow-up over a 3-year period included periodic identically taken radiographs, electric and galvanic pulp tests and tests for cytotoxic antibodies. Almost complete closure of the apex of the tooth has occurred with no sign of root resorption. The transplant has remained vital, and no production of antibodies against the graft has occurred.

Adult↗
PubMed1998

[Definitive injuries to the teeth. Lesions of hard tissue and pulp].

Tooth infraction and enamel fracture are the most simple traumatic crown lesions. When necessary the lesions can be covered with composite material. Follow-up of the traumatized tooth is necessary since pulp necrosis and obliteration can develop. In case of an uncomplicated fracture involving enamel and dentine immediate protection of the dentinal wound is important for the preservation of tooth vitality. In case of a negative vitality test, an endodontic treatment will be performed in case of a tooth with open apex only when supplemental clinical and or radiological signs of pulp necrosis are present. When a complicated enamel-dentine fracture is present, an endodontic treatment will be performed when root formation is complete. In case of a wide open apex, a pulp capping, partial pulpotomy or cervical pulpotomy will be performed in order to preserve vitality of pulpal tissues at the level of the root. Crown root fractures can be superficial, deep or vertical. In case of a superficial localisation of the fracture line, restoration with composite material or with the fractured tooth segment is indicated. Deep crown-root fractures can only be restored when the fracture line is localized not deeper than at 1/3 of the length of the root. In case of a vertical fracture, extraction is the only possibility. Root fractures on immature teeth are in most cases unilateral and have a good prognosis. In teeth with completed root formation, fractures at the level of the cervix have a poor prognosis. The fractured segment will be removed. Only when the remaining root segment is long enough, this part can be maintained. In case of a fracture at the mid-root level, repositioning and rigid splinting for a period of 8 weeks is necessary. When the tooth becomes non-vital, endodontic treatment is performed on the coronal part. Root fracture in the apical part does not necessary result in enhanced tooth mobility and immobilisation is not always necessary. Healing of a root fracture is only possible when the tooth is immobilized for a sufficiently long period. Regular control of tooth vitality is necessary since pulp necrosis can lead to an inflammatory reaction at the level of the fracture line.

Dental Enamel↗
PubMed2006

Bone level around endodontically treated teeth in periodontitis patients.

OBJECTIVES: This retrospective study compared the marginal bone level of teeth with root canal fillings with contra-lateral teeth without. METHODS: Of 286 consecutive patients (> or =35 years), referred to practice for periodontology in the Netherlands, 67 full sets of radiographs contained > or =1 endodontically treated tooth and its contra-lateral tooth without root canal treatment. Bone level at the mesial and distal of these teeth was scored from the CEJ. In multi-rooted teeth, the presence of interradicular radiolucency was assessed. The presence of posts, and periapical radiolucencies was assessed. Analysis for differences between treated teeth and contra-laterals was controlled for tooth surface, presence of a post and tooth type. RESULTS: The mean distance from the root filling to the apex was 2.6 mm. Periapical radiolucencies were found in 14%. The mean bone level was at 4.3 mm for endodontically treated teeth and at 3.7 mm for contra-laterals. Significantly more bone loss (0.6 mm) was found at the endodontically treated teeth. No difference was found between mesial and distal, teeth without and with posts and different tooth types. The presence of interradicular radiolucency was more frequent in endodontically treated teeth (OR 2.1, p(McNemar test)=0.039). CONCLUSION: In periodontitis patients, teeth with endodontic treatment had more bone loss as compared with untreated contralaterals.

Adult↗
PubMed1995

Efficacy of XeCl-308 excimer laser in fusing hydroxyapatite to seal the root apex.

Sealing the root apex during apical surgery is important for a successful outcome. The effect of XeCl-308 nm excimer laser irradiation on the fusion and seal of hydroxyapatite to the root apex was tested in extracted human teeth. Twenty-four roots of intact single-rooted premolars were instrumented to size 30 K-file at the apex leaving a patent apical foramen. The apex of each tooth was covered with a freshly prepared paste of hydroxyapatite powder mixed with saline. The samples were then divided into two groups. In 12 teeth, the apical area was irridiated with XeCl-308 nm excimer laser at a fluence of 0.7 J/cm2 for 5 s with pulse repetition rate of 25 Hz and a spot size of 0.13 cm2 immediately after the hydroxyapatite application. In the other 12 teeth, no laser treatment was performed after the hydroxyapatite application. The roots were mounted on a model for the detection of radicular leakage of hydrogen peroxide. The hydrogen peroxide leakage of each sample was measured and the difference between the test groups compared. The ability of the hydroxyapatite plug to prevent hydrogen peroxide leakage at the apex was also tested by applying compressed air from the triple syringe on the coronal access preparation for 2 min. Apical leakage was found in four teeth in the lased group and in eight teeth in the non-plased group. However, the difference between the groups was not statistically significant. Compressed air applied to the coronal access caused hydrogen peroxide leakage in all the teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Chi-Square Distribution↗
PubMed2001

A finite element model of apical force distribution from orthodontic tooth movement.

This study was undertaken to determine the types of orthodontic forces that cause high stress at the root apex. A 3-dimensional finite element model of a maxillary central incisor, its periodontal ligament (PDL), and alveolar bone was constructed on the basis of average anatomic morphology. The maxillary central incisor was chosen for study because it is one of the teeth at greatest risk for apical root resorption. The material properties of enamel, dentin, PDL, and bone and 5 different load systems (tipping, intrusion, extrusion, bodily movement, and rotational force) were tested. The finite element analysis showed that purely intrusive, extrusive, and rotational forces had stresses concentrated at the apex of the root. The principal stress from a tipping force was located at the alveolar crest. For bodily movement, stress was distributed throughout the PDL; however, it was concentrated more at the alveolar crest. We conclude that intrusive, extrusive, and rotational forces produce more stress at the apex. Bodily movement and tipping forces concentrate forces at the alveolar crest, not at the apex.

Alveolar Process↗