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At least 307 records · Page 17Linked to original sources
PubMed1987

A quantitative electron-microscopic analysis of the axons at the apex of the canine tooth pulp in the dog.

The morphology of the dog intradental nerves has not been studied in detail, although dogs have been increasingly used in electrophysiological experiments on pulp nerve function. In this investigation electron microscopy and morphometric analysis were used to study the number and dimensions of the axons at the apex of the dog canine tooth. Two upper and two lower canines, each taken from a different animal, were used. The average number of axons entering a tooth was 2,089 (range: 1,241-3,034), 74.3% (range: 62.2-77.9%) of which were unmyelinated. The mean circumference of the myelinated and unmyelinated axons ranged from 11.1 to 13.9 microns and from 1.3 to 1.7 micron, respectively. Of the myelinated axons 13.7% had a circumference over 19 microns, which is considered to be the upper limit of the A delta-class. Of the unmyelinated axons 13.8% showed apposition to each other and 20% were partly exposed to the extracellular space; these features could, in part, offer the morphological basis for the extreme pain sensitivity of the tooth. The findings of the present study were considered in general to be comparable to the results of earlier histological and electrophysiological studies on pulp nerves of different species. Thus, it seems that the dog tooth is an adequate model for studying the pulp nerve function and morphology.

Animals↗
PubMed1990

[Dens in dente. Apropos of a clinical case].

Dens in dente was described by authors as tooth characterized by a non limited apex. This tooth was localized into right upper lateral incisor and was diagnosed for an eight old child consulting for a canine incisor region tumefaction. This anomaly was only diagnosed by radiography showing radio-opaque structures in the pulpar chamber.

Child↗
PubMed2005

Long term radiographic study of bilateral second premolars with immature root treated by apexogenesis and apexification.

A ten-year-old girl broke the central cusps of the mandibular second premolars. The mandibular right second premolar was treated with apexification and the left with apexogenesis. These methods were chosen in view of the presented clinical symptoms, radiographic findings, and outcome of bacterial cultures of root canal samples. At postoperative 2 years 8 months, disappearance of the focus, closure of the root canal, and formation of the root apex were observed in both mandibular premolars. The mandibular left second premolar demonstrated a nearly normal root formation and root apex morphology. Immediately beneath the extracted pulp, regular, uniform, and thick hard tissue was formed. Meanwhile, in the mandibular right second premolar, root growth was suspended, making the root short, and the contour was constructed in such a way that it encircled the distal apical area from the mesial side forming the root apex.

Bicuspid↗
PubMed1999

Non-vital immature permanent incisors: factors that may influence treatment outcome.

This study examines the treatment of non-vital immature permanent incisors using the calcium hydroxide apexification technique. The objectives of the present study were to determine the speed and location of barrier formation and those factors discernible at presentation and during treatment which may be related to it. Forty-four non-vital immature incisors undergoing calcium hydroxide apexification were reviewed in detail. All cases were reviewed every 8-12 weeks for up to 18 months, or until apexification occurred. Details of the time and nature of the injuries and treatment were recorded. The degree of apical development prior to treatment was assessed, and barrier formation, location and time were noted. Mean time to barrier formation was 34.2 weeks (range 13-67 weeks). The strongest predictor of rapid barrier formation was the rate of change of calcium hydroxide and a barrier also formed more rapidly in cases with narrower initial apical width. There was evidence of displacement and a higher mean time for barrier formation in half of the cases. The presence of an abscess was the weakest predictor of rapid barrier formation and the effect was not significant (P = 0.280). The barrier was located at the apex in 28 cases (63.6%) and the distance from the barrier to the apex for the remaining 16 (36.4%) varied from 1 mm to 5 mm. The number of placements of calcium hydroxide varied from 1 to 4 with a mean of 1.9, and there was a higher mean number of calcium hydroxide placements in the cases where the barrier was located at the apex.

Analysis of Variance↗
PubMed1999

Apex formation during orthodontic treatment in an adult patient: report of a case.

This clinical report describes an apexification procedure on a maxillary left central incisor in a 34-year-old male who was also receiving active orthodontic treatment. The pulp of the tooth had become necrotic following a traumatic injury when the patient was 8 years of age. Despite the tooth undergoing active orthodontic repositioning with fixed appliances, root-end closure occurred uneventfully and within 3 years.

Adult↗
PubMed2004

Apex locators: update and prospects for the future.

The accuracy of working length determination in root canal treatment plays a crucial role in the treatment and prevention of periapical disease. Since the introduction of the first apex locator by Sunada in 1961, new and more accurate devices have been developed. Electronic apex locators reduce the number of radiographs required and may detect root canal perforations and fractures. Third and fourth generation apex locators can operate in the presence of intact or necrotic tissue, blood, inflammatory exudates, and various irrigants. The Raypex 4 and the Apex NRG novel apex locators are discussed in detail.

Dental Instruments↗
PubMed2004

[Apical foramen position on mesio buccal root of the maxillary first molar. Study in Senegalese population].

The maxillary first molar is submitted to frequent endodontic treatment and more over, it presents the highest failure rates, often in relation with his mesio-buccal root. Several studies about failures factors showed implication of root canal anatomy often in relation with the frequency of second canal. However, other failures factors, as the foramen situation, which is very important in endodontic practice, could increase the failure rate. The aim of this study was to determine the foramen situation in Senegalese people. The results showed 63.85% of excentric foramina (83 out of 130). 86% of excentric foramina were located at 1.5mm radiology apex.

Adolescent↗
PubMed2003

Comparison between panoramic and intra-oral radiographs for the assessment of alveolar bone levels in a periodontal maintenance population.

BACKGROUND: Information about the agreement between intra-oral (I-O) and panoramic (OPG) radiographs is limited. AIMS: : (1) To assess the agreement between I-Os and OPGs for direct measurements of the distance between the cemento-enamel junction (CEJ) and the alveolar bone level (BL) as well as the proportional values in relation to the root length (CEJ-BL/root length), and (2) to explore the symmetry between the left- and right-side measurements. MATERIAL AND METHODS: I-Os and OPGs were studied in 292 periodontal maintenance subjects (mean age 55.5 years, SD+/-12.6) with on average 22.4 teeth (SD+/-4.1 range: 6-28). The images were measured using a PC software program. Site-based I-O and OPG values for CEJ-BL as well as CEJ-BL/root length were compared. OPG values of CEJ-BL/root length values between the left and right sides were also studied. RESULTS: A total of 11,395 linear distances (CEJ-BL plus CEJ-apex) from the I-Os and 21,462 linear distances from the OPGs were measured. The intra-class correlation coefficients (ICCs) between sets of readings of CEJ-BL varied between 0.80 and 0.89 (p<0.001), with the best agreement for tooth 22 (ICC: 0.89; 95% CI: 0.83-0.92). The ICCs for CEJ-BL/root length varied between 0.54 and 0.92. Mean differences between I-O and OPG values were in the 0.00-0.04 mm range for the CEJ-BL/root length comparisons. The maxillary anterior sextant demonstrated a 1.4 x enlargement by OPG for the CEJ-BL/root length comparisons. No distortions were observed for mandibular sextants. Left- and right-side symmetry of periodontal bone loss was demonstrated. ICC varied between 0.79 (95.00% CI: 0.71-0.84, p<0.01) and 0.53 (95.00% CI: 0.36-0.65, p< 0.01). CONCLUSIONS: I-O and OPG radiograph readings are in great agreement. Alveolar bone loss appeared to have a symmetrical distribution pattern. Hence for periodontal assessments, OPG radiographic readings may, at least in part, substitute for full-mouth periapical radiographic evaluation.

Alveolar Bone Loss↗
PubMedDate not supplied

Electronic apex locator: a useful tool for root canal treatment in the primary dentition.

The purpose of this study was to test the ability of an electronic apex locator, Root ZX to measure the root canal length in primary teeth with partial resorption. Twenty extracted primary molars were embedded in an alginate model imitating in vivo conditions. Root ZX and radiographic measurements were compared in dry and wet environments to the actual tooth length. Root ZX identified the tooth length at the most coronal portion of the resorption. The content of the root canal did not influence the results. No statistical differences were found between electronic, radiographic and actual tooth length measurements, although the radiographic measurements were longer than the electronic ones. It is suggested that Root ZX is a preferable auxiliary device to measure root canal length in the primary dentition.

Child↗
PubMed2002

The ability of root ZX apex locator to reduce the frequency of overestimated radiographic working length.

The aim of this in vitro study was to evaluate the ability of the Root ZX device to avoid instrumentation beyond the apical foramen in premolars after conventional working length radiography. Thirty extracted premolars with 43 root canals were subjected to radiographic and electronic working length determination. Radiographic working length determination resulted in overestimation in 51% of the root canals, although the measuring file tip was located to be 0 to 2 mm short of the radiographic apex. Electronic working length measurements with the Root ZX reduced the percentage of overestimation to 21%. In 6 root canals (14%), both radiographic and electronic working length measurements led to overestimation. It is concluded that complementing radiographic working length determination with electronic apex locator measurements may help to avoid overestimation beyond the apical foramen in premolars.

Bicuspid↗
PubMed1998

Microorganisms in closed periapical lesions.

The purpose of this study was to investigate the microorganisms of strictly selected closed periapical lesions associated with both refractory endodontic therapy and pulpal calcification. Definitive criteria were established that assured complete clinical isolation of the periapical lesion from the oral and periodontal environment. A total of 13 criteria-referenced lesions were selected from 70 patients with endodontic surgical indications. A well controlled culturing method was used in all cases and samples were taken by one clinician at three separate sites during each surgery. Samples taken at the surgical window and within the body of the lesion served as controls, whilst a third sample was taken at the apex. In all 13 cases, samples taken from the apex yielded microorganisms comprising 63.6% obligate anaerobes and 36.4% facultative anaerobes. Prevalence of the isolated species was 31.8% for Actinomyces sp., 22.7% Propionibacterium sp., 18.2% Streptococcus sp., 13.6% Staphlyococcus sp., 4.6% Porphyromonas gingivalis, 4.6% Peptostreptococcus micros and 4.6% Gram-negative enterics. The results of this investigation indicate that closed periapical lesions associated with calcified teeth or those resistant to root canal treatment harbour bacteria. The inability to eradicate all root canal microorganisms during root canal treatment, along with anatomical factors, may allow further bacterial colonization of the root apex and surrounding periapical tissues, and consequently prevent healing.

Bacteria, Anaerobic↗
PubMed2002

Influence of the canal contents on the electrical assisted determination of the length of root canals.

The purpose of this study was to compare the influence of the root canal status on the determination of the root canal length by an electronic apex locator in vital and necrotic canals and canals with root canal filling retrieval. One hundred seven teeth with a total of 171 canals with various contents (105 vital pulp, 47 necrotic pulp, and 19 retrieval of root canal filling materials) were measured for root canal length in vivo with the AFA Apex Finder. The distance between the file tip and the radiographic apex was also determined on radiographs. In 86% of the evaluated roots, the file tip position as indicated by the Apex Finder was located within 0.5 mm of a point 1.0-mm short of the radiographic apex. The Apex Finder showed higher accuracy for determining the apical constriction in vital canals (93.9%) than in necrotic canals (76.6%), and this difference was statistically significant (p < or = 0.05). The Apex Finder indicated the point -1 mm +/- 0.5 mm in canals with retrieval of root canal filling materials in 68.4% of these cases, but because of the small number of retrieval cases, this is not comparable statistically with vital and necrotic cases. The authors concluded that the AFA Apex Finder is highly accurate in vital canals.

Dental Pulp↗
PubMed2005

Effective factors including periodontal ligament on vertical root fractures.

The purpose of the present study was to analyze effective factors including periodontal ligament on vertical root fractures (VRFs). Eighty maxillary central incisors were assigned to eight groups, depending on master apical file (MAF) size, loading point and existence of a simulated periodontal ligament (PDL). The gutta-percha in the root canal was vertically pressed with a Co-Cr rod using a universal testing machine. An ordinal logistic analysis was employed to determine significant factors. VRFs were observed in 88.8% of the specimens but no horizontal fractures were found. There were three types of VRFs: partial fracture not involving the apex (PF, 41.3%), partial fracture involving the apex (AF, 40.0%), and complete fracture (CF, 7.5%). MAF size significantly affected VRFs (p < 0.05); large MAF size exhibited more partial fractures involving the apex. Loading point and existence of PDL did not affect VRFs.

Dental Instruments↗
PubMed2001

Frequency of overinstrumentation with an acceptable radiographic working length.

The aim of this in vitro study was to determine how frequent a seemingly accurate working length ending radiographically 0 to 2 mm short of the radiographic apex resulted in an instrumentation beyond the apical foramen. Under simulated clinical conditions working lengths of 169 root canals were radiographically determined in 91 extracted teeth. In all cases the measuring files adjusted to the final working length (Iwork) were located 0 to 2 mm short of the radiographic apex. Iwork was subsequently compared with the actual reference length (Iref) representing the distance between the apical foramen and the coronal reference. Instrumentation beyond the apical foramen (Iwork > ref) occurred in premolars in 51% (95% confidence interval: 36%; 66%) of the cases, in molars in 22% (95% confidence interval: 14%; 30%), and in anterior teeth in no case. These results suggest that in premolars and molars a radiographically working length ending 0 to 2 mm short of the radiographic apex provides, more often than expected, a basis for unintentional overinstrumentation.

Bicuspid↗
PubMedDate not supplied

Computed tomography-anatomy of the normal feline nasolacrimal drainage system.

Computed tomography (CT) of the nasolacrimal drainage system with and without contrast medium (barium sulfate) was used to create an anatomic basis for clinical evaluation in domestic cats. To evaluate and compare the anatomical findings, three casts were carried out and were followed by CT examinations. These CT series were also used for a three-dimensional (3D) reconstruction of the nasolacrimal drainage system within surrounding structures. In noncontrast CT images, osseous structures limiting the nasolacrimal drainage system are easily recognizable. In most cats, this allows the identification of the nasolacrimal drainage system even without contrast enhancement. A distal part of the lacrimal sac adjoins directly to the respiratory mucosa of the nasal cavity without an osseous protection. Thus, this may represent a predilection site for infiltration of adjacent pathologic processes from the nasal cavity onto the lacrimal sac. The nasolacrimal duct begins on level with the maxillary third premolar tooth. The apex of the root of the canine tooth is situated very close to the nasolacrimal duct. This close topographic relation may lead to problems with the nasolacrimal drainage system. In domestic cats the nasolacrimal drainage system consists of a descending and a horizontal part, which form an angle of approximately 90 degrees for unhindered drainage of the lacrimal fluid.

Animals↗