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At least 883 records · Page 49Linked to original sources
PubMed2000

Frequency of second mesiobuccal canals in maxillary molars as determined by use of an operating microscope: a clinical study.

Operating microscopes have recently been introduced to facilitate treatment of surgical and nonsurgical endodontic cases. The aim of this study was to determine in an in vivo clinical study if the use of an operating microscope would increase the number of second mesiobuccal canals located and obturated in maxillary first and second molars. Two hundred maxillary first and second molars treated with the aid of a microscope were evaluated. The number of second mesiobuccal canals that could be negotiated and obturated within 4 mm of the apex was recorded. Thirty percent of all maxillary molars had a negotiable second mesiobuccal canal. Evaluated separately, 33.1% of the maxillary first molars and 24.3% of the second molars had a negotiable second mesiobuccal canal. Results indicated that use of a surgical microscope did not increase the number of second mesiobuccal canals located, compared with those reports where access preparations were modified and the microscope was not used.

Dental Pulp Cavity↗
PubMed2003

Natural selection on molar size in a wild population of howler monkeys (Alouatta palliata).

Dental traits have long been assumed to be under selection in mammals, based on the macroevolutionary correlation between dental morphology and feeding behaviour. However, natural selection acting on dental morphology has rarely, if ever, been documented in wild populations. We investigated the possibility of microevolutionary selection on dental traits by measuring molar breadth in a sample of Alouatta palliata (mantled howler monkey) crania from Barro Colorado Island (BCI), Panama. The age at death of the monkeys is an indicator of their fitness, since they were all found dead of natural causes. Howlers with small molars have significantly decreased fitness as they die, on average, at an earlier age (well before sexual maturity) than those with larger molars. This documents the existence of phenotypic viability selection on molar tooth size in the BCI howlers, regardless of causality or heritability. The selection is further shown to occur during the weaning phase of A. palliata life history, establishing a link between this period of increased mortality and selection on a specific morphological feature. These results provide initial empirical support for the long-held assumption that primate molar size is under natural selection.

Alouatta↗
PubMed2004

The radix entomolaris in mandibular first molars: an endodontic challenge.

AIM: To present cases of mandibular first molars with an additional distolingual root (radix entomolaris, RE) and to survey the literature on the incidence of this anatomical feature. SUMMARY: A major anatomical variant of the two-rooted mandibular first molar is a tooth with an additional distolingual and third root: the RE. The prevalence of these three-rooted mandibular first molars appears to be less than 3% in African populations, not to exceed 4.2% in Caucasians, to be less than 5% in Eurasian and Asian populations, and to be higher than 5% (even up to 40%) in populations with Mongolian traits. A total of 18 cases (12 root filled and six extracted mandibular first molars) with an RE were collected during the years 2000-2003 in patients of Caucasian origin. As far as the access was concerned, entering the root canal in the RE required a modification of the opening in a distolingual direction resulting in a trapezoidal opening cavity. None of the orifices was located midway between the mesial and distal root component. Based on the anatomy of the extracted samples and the bending of ISO 10 files after scouting of the root canal in the RE, three types of curvature were detected: (I) straight or no curvature (two cases); (II) coronal third curved and straight continuation to the apex (five cases); and (III) curvature in the coronal third and buccal curvature from the middle third or apical third of the root (11 cases). KEY LEARNING POINTS: Clinicians should be aware of this unusual root morphology in mandibular first molars in Caucasian people. Radiographs exposed at two different horizontal angles are needed to identify this additional root. The access cavity must be modified in a distolingual direction in order to visualize and treat the RE, this results in a trapezoidal access cavity.

Adult↗
PubMed2006

C-shaped root canal in a maxillary first molar: a case report.

AIM: This case report presents an unusual C-shaped root canal system in a maxillary first molar tooth. SUMMARY: Although C-shaped root canals are most frequently seen in the mandibular second molar, they may also appear in maxillary molars. A literature search revealed only a few case reports of C-shaped root canal systems in maxillary molars. The present case describes a C-shaped canal in the buccal root of a maxillary first molar. The endodontic access cavity displayed two canal orifices, one leading to the canal system in the buccal root, the other into the palatal root canal system. In the buccal root, what appeared to be the mesial and distal canals joined to form a single C-shaped canal. KEY LEARNING POINTS: --Careful examination of radiographs and the internal anatomy of teeth is essential.-- The location and morphology of root canals should be identified at high magnification under the microscope.

Adult↗
PubMed2006

Root canal treatment in Denmark is most often carried out in carious vital molar teeth and retreatments are rare.

AIM: To study the reasons given by a representative sample of Danish general dental practitioners (GDPs) for undertaking root canal treatment and, to investigate their confidence in performing root canal treatment on molar teeth. METHODOLOGY: A questionnaire was sent to 600 Danish GDPs randomly selected from the roster of the Danish Dental Association. They were asked to recall various factors about their experience of the last root filling they completed, including the reason for treatment and the pulp diagnosis. Self-assessments on 100-mm visual analogue scales (VAS) were reported concerning the confidence in performing root canal treatment of a molar. End-point definitions were 'very easy' (0) and 'very difficult' (100), respectively. Time reports of molar treatments were given in categorized groups. RESULTS: The most frequent reason for performing root canal treatment was caries within the tooth involved (55%). The majority of treatments involved teeth with vital pulps (54%). Retreatments were carried out in 2% of the cases. The confidence in performing root canal treatment varied but was relatively high, expressed as VAS-values below 50. The creation of an aseptic working field was regarded as the most difficult procedure followed by root canal preparation. Fifty-six percent of the responders stated a time frame of 46-75 min to complete root filling in a molar tooth. CONCLUSIONS: Root canal treatment in Denmark was reported to be undertaken most often because of caries. Treatment was typically performed in molar teeth with vital pulp. Even though apical periodontitis was frequently noted in root filled teeth, retreatments were rare. From a subjective perspective root canal treatment was not considered to be very difficult and was carried out relatively rapidly.

Analysis of Variance↗
PubMed1993

Taurodontism of the mandibular first permanent molar distinguishes between the tricho-dento-osseous (TDO) syndrome and amelogenesis imperfecta.

The diagnosis of tricho-dento-osseous (TDO) syndrome is often confused with that of a variant of amelogenesis imperfecta (AI) which shows similar dental features of hypomaturation-hypoplastic enamel defects and putative taurodontism. In this controlled study, an objective, biometric measurement technique was used to determine the prevalence and severity of taurodontism of the mandibular first permanent molar in 23 patients with AI and one patient with TDO syndrome compared with age- and sex-matched controls. The published radiographs of previous cases of TDO and hypomaturation-hypoplastic AI were also reviewed with regard to the presence and severity of taurodontism. The results indicate that in all cases of TDO, taurodontism of the molars including mandibular first permanent molars was consistently present and in a severe form. By contrast, the taurodontic defects present in all cases of AI, including the hypomaturation-hypoplastic variant were not significantly different from matched, healthy controls. Of significance is the fact that in all the AI cases, none of the taurodontic defects were present on the mandibular first permanent molars. The results indicate that true taurodontism as indicated by a change in the mandibular first permanent molars occurs only in the TDO syndrome. This feature may be used to differentiate clearly between TDO and AI.

Abnormalities, Multiple↗
PubMed1982

Bone loss of furcated mandibular molars. A longitudinal study.

Periodontal bone destruction adjacent to furcations of molar roots has been considered to be unfavourable for the prognosis of the involved teeth. Several alternative modes of treatment have been reported. The objective of this study was to find out how important the furcation problem is. A study was conducted on the prevalence, degree and development of bone destruction between the roots of furcated mandibular molars in a sample of 221 individuals observed over a period of 13 years. The state of the interradicular bone septa was assessed from orthopantomographs and bite-wing radiographs. Radiographs were available from 1965, 1971, 1974 and 1978. The degree of bone destruction was measured in relation to the root length. About 90% of remaining molars (in 1965) were furcated. The frequency of bone destruction increased from 18% in 1965 to 32% in 1978. Only 1.1-2.7% of the molars had bone loss affecting more than 50% of the distance vertex to apex. About 9% of the furcated molars were lost during the observation period. However, the percentage of teeth lost due to progressive furcation involvement during the 13 years was estimated to be only 2.5%.

Adult↗
PubMed1991

The width of plaque-free zones on primary molars with attachment loss.

The width of plaque-free zones on stained surfaces of extracted primary molars showing attachment loss was measured. The teeth were divided into 4 groups: maxillary first and second molars, mandibular first and second molars. 30 measurements were made under a stereomicroscope on each of the 4 surfaces in every group. The plaque-free zone had a mean width of 1.75 +/- 0.49 mm and a range of 1.0-4.3 mm. The plaque-free zone was significantly (P less than 0.001) wider on the proximal surfaces (1.94 +/- 0.56 mm) than on the combined buccal and lingual surfaces (1.56 +/- 0.32 mm). There was no difference between the 2 proximal surfaces while the lingual surfaces gave higher values than the buccal ones. On the second and on the lower primary molars, the plaque-free zones were wider than on the first and on the upper molars.

Dental Plaque↗
PubMed1997

Treatment of 3rd molar-induced periodontal defects with guided tissue regeneration.

Recent reports provide evidence of increased attachment levels when using guided tissue regeneration (GTR) techniques for the treatment of periodontal defects. Periodontal defects frequently occur at the distal aspect of mandibular 2nd molars which are next to mesioangular impacted 3rd molars that have oral communication. The purpose of this study was to determine whether the use of GTR can enhance probing attachment levels (PALs) following extraction of mesioangular impacted third molars. 12 patients with bilateral soft tissue impacted mandibular 3rd molars entered this split mouth study. After extractions, the previously exposed distal root surface of the 2nd molars were debrided. The defects on the randomly selected experimental sites were covered with expanded polytetraflouro-ethylene (e-PTFE) membrane and the tissue was replaced to cover the membrane. Membranes were removed after 6 weeks. Control sites were treated identically except no membrane was placed. GI, P1I, PD, PAL and BOP records were obtained at 0, 3 and 6 months. The use of barrier material did not provide statistically-significant differences in PAL when comparing experimental versus control sites. Nevertheless, PAL gain was consistently greater at 3 and 6 months when GTR techniques were used in sites with deep impactions.

Adult↗
PubMed1975

Molar tooth attrition in a selected group of Nigerians.

A study of the degree and gradient of attrition was undertaken on 352 molar teeth of 88 selected Nigerian subjects. A method for the quantification of attrition experience per molar tooth is described. There is a close correlation between age and the degree of attrition of the first molar. This finding may be of value in age determination in forensic odontology. The wear on the first molar is about two stages ahead of that on the second and third molars. It is suggested that the degree of tooth attrition may be an index of masticatory activity.

Adult↗
PubMed1990

Patients' retrospective preference for extraction of asymptomatic third molars.

The purpose of this study was to determine the personal utility of asymptomatic third molar removal in military patients. From 1 to 30 days (mean = 7.4) after the extraction of one or more third molars, 100 returning patients (all male, mean age = 20.1) were asked to respond to hypothetical questions concerning the extraction of asymptomatic third molars. If the likelihood of third molars ever having to be removed was given as 10%, 50%, and 100%, then 45%, 61%, and 88% of responses, respectively, showed preference for immediate extraction. When respondents chose to delay treatment until there was a problem, no likelihood group would tolerate more than 2.77 additional days of post-extraction pain before changing their preference to immediate extraction. 87% of respondents preferred extractions prior to a deployment which would make treatment delivery difficult, and 89% prior to becoming a civilian at which time treatment might no longer be free. The results indicate general acceptance of the strategy of prophylactic third molar removal among a sample of military patients who have undergone pre-treatment counseling and the surgical procedure. A question remains as to the personal utility that might be measured prior to surgery.

Adult↗
PubMed1992

Caries prevalence in primary teeth as a predictor of early fissure caries in permanent first molars.

The study aimed to examine the validity of employing the caries experience of the primary dentition for predicting early caries in the permanent first molar fissures. Subjects consisted of 192 children who were followed for 2 yr, 91 of whom were pursued for a further year, all receiving semiannual check-ups. The caries prevalence in the primary dentition (dmft), excluding incisors, was recorded at baseline, which was the year the children became 6. Fissure caries in the permanent first molars was recorded as being confined to enamel or dentin, based on findings during cavity preparation. The correlation between dmft and the number of intact permanent first molars was -0.368 and -0.337 after 2 and 3 yr observation respectively. When the children were grouped according to their dmft, a statistically significant relationship was found between the dmft and the number of intact molars in each individual. The positive and negative predictive values as well as the sensitivity and specificity of different dmft values were calculated, and the relationship between them illustrated by the use of ROC curves. Even if there are no specific dmft values which seem obviously favorable for the purpose, these data give information relevant in planning for large scale use of fissure sealing in preventing early fissure caries in permanent first molars.

Child↗
PubMed1988

Pathological sequelae of "neglected" impacted third molars.

An NIH conference on "Removal of Third Molars" debated the need for removal of asymptomatic impacted teeth with no evidence of pathology but stressed the need for long-range studies. The assumption is that "neglected" impacted third molars (ITMs) will sometime cause serious pathology. Examination of panoramic radiographs of 11,598 patients revealed 1,756 patients with 3,702 impacted teeth; average age 47 years, and an average retention period approximately 27 years. Dentigerous cystic changes occurred in about 30 ITMs (0.81%), internal resorption in 16 (0.43%), periodontal ligament damage and bone loss distal to the 2nd molar 166 times (4.48%), and pressure resorption of the 2nd molar 113 times (3.05%). No great surge in pathology occurred with increasing age. Some type of pathological change can be expected eventually in approximately 12.0% of an impacted 3rd molar population and 1.82% of the general population. A reappraisal of routine removal of ITMs might be indicated.

Adult↗
PubMed1989

Secondary retention of permanent molars: a histologic study.

The etiology of secondary retention is not well understood, but ankylosis is often considered to be an important factor in primary molars. Data concerning the mechanism of secondary retention in the permanent dentition are insufficient, although a possible role of ankylosis has been suggested. In order to analyze the frequency of occurrence and localization of ankylosis in secondarily retained permanent teeth, 26 secondarily retained molars and for comparison six normal molars were studied histologically. These data were compared with the clinical and radiographic findings. Areas of ankylosis were observed along the roots of all secondarily retained molars. In 81% of the cases these areas were located at the bifurcation and interradicular root surface. No signs of ankylosis were found in normal molars. When these results were compared with the clinical and radiographic data, it was obvious that the latter gave many false negative results, because the areas of ankylosis were often too small to be detected clinically or radiographically.

Adolescent↗
PubMed1977

A longitudinal study on the effect of unilateral extraction of primary molars.

The effect of unilateral extraction of the first or second primary molar on space conditions, need for orthodontic treatment, and eruption stage of permanent canines and second molars has been studied longitudinally in two groups. In Group 1 the first primary molar had been extracted early in 13 cases in the maxilla and in 14 cases in the mandible. In Group 2 the corresponding figures for the second primary molar were 14 and 24 for the maxilla and mandible, respectively. The space on the extraction side in Group 1 was significantly less than on the control side at the age of 9 but not at the age of 13. In Group 2 there was significantly less space on the extraction side than on the control side at the two registration ages (10.5 and 12 years). Need for orthodontic treatment was low in Group 1 and high in Group 2. As for eruption stage of permanent canines and second molars, no significant differences were found between the extraction side and the control side in the two groups.

Child↗
PubMed1979

Assessment of age-at-death from mandibular molar attrition in medieval Danes.

Stages of occlusal attrition of the permanent mandibular molars were recorded in 235 Danish medieval skulls, 52 of which were in various states of mixed dentition. For the first and second molar, ages at emergence and ages at occurrence of the earlier stages of attrition were estimated from the mixed dentitions, on the assumptions 1) that the age at eruption of a given number of permanent teeth was similar in medieval and contemporary Danish children, and 2) that the rate of attrition was similar for the first and second molars. Estimation of ages at occurrence of the later attrition stages and of the age at third molar emergence was based on percentage frequency distributions of the stages of attrition using reiterative calculating procedures. Third molar emergence was estimated at the early age of 14 years. It is argued that assessments of age-at death could be made fairly accurately for the age range 5-30 years, and with decreasing accuracy until about 40 years of age.

Adolescent↗
PubMed1982

Effect of cadmium on calcium, magnesium and phosphorus content of rat molars.

Eleven groups of Wistar rats, 10 animals in each group, received graded doses of CdCl2 in the drinking water from conception until sacrifice at the age of 10 weeks. The Ca and Mg contents of whole molars as well as enamel and dentin for each group were recorded by atomic absorption spectrophotometry (AAS). The inorganic P content of the control and three experimental groups was measured by colorimetry. Four molars from each of eight additional animals, four controls and four from the 22.5 parts/10(6) Cd group were ground transversely and subjected to X-ray microanalysis. AAS analyses showed that the Ca level of whole molars increased significantly with a Cd supply above 2.5 parts/10(6). The Ca content was significantly correlated with the Cd contents of the same teeth. The increased Ca seemed to be in the enamel. The Mg content decreased significantly with Cd doses below 12.5 parts/10(6). This decrease seemed to be in dentin. The P level of the molars increased following Cd supply, but not significantly so. The X-ray spectra demonstrated that there were no significant differences between the Ca/P ratios of the two groups, either in enamel or in dentin. It is concluded that absorption of Cd alters the normal Ca, Mg and P levels in rat molars. This may reflect a disturbance of Ca, P and Mg metabolism in the organism generally.

Animals↗
PubMed2006

Combining paracetamol with a selective cyclooxygenase-2 inhibitor for acute pain relief after third molar surgery: a randomized, double-blind, placebo-controlled study.

Severe pain after third molar surgery is often encountered and more effective treatment regimes are warranted. The objective of this study was to evaluate if the combination of paracetamol and rofecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, improves analgesic effects following third molar surgery compared with rofecoxib alone. Paracetamol alone was also evaluated. Altogether 120 patients with moderate to severe pain after third molar surgery were given a single postoperative dose of one of the following treatments: rofecoxib + paracetamol; rofecoxib alone; paracetamol alone; or placebo. Patients assessed level of pain and pain relief every 30 min for 8 h after surgery, and made a global evaluation of the medication 4 and 8 h after surgery. Paracetamol and rofecoxib combined improved the analgesic effect compared with rofecoxib alone for the first 1.5 h. Rofecoxib alone and the combination of paracetamol and rofecoxib had a significantly better analgesic effect than paracetamol alone from 3 h onwards. The early onset of pain relief for the combination of paracetamol and rofecoxib, compared with rofecoxib alone, could be of great importance when treating acute pain after third molar surgery. After data collection for this study, rofecoxib was withdrawn from the market as a result of reported fatal cardiovascular events. Whether this is relevant for short-term use is unknown, but it has to be considered before rofecoxib may be used for pain relief following third molar surgery.

Acetaminophen↗