Primer premolar inferior con dos conductos y doble trayecto fistuloso: caso clínico / First lower premolar with two canals and double fistulous path: a clinical case

El tratamiento endodóntico del primer premolar inferior, cuando presenta varios conductos o varias raíces puede ser un gran desafío. En el presente trabajo se describe un caso clínico de un paciente de sexo masculino de 60 años de edad que concurre al Servicio de Guardia de la Facultad de Odontología de la Universidad de Buenos Aires (FOUBA). Al examen clínico y radiográfico se descubre la presencia de dos trayectos fistulosos que corresponden a la misma pieza dentaria con diagnóstico de absceso alveolar crónico. Concluimos que el operador debe realizar un minucioso diagnóstico, y analizar y conocer las diferentes configuraciones anatómicas para tratarlas adecuadamente, aumentando así las probabilidades de éxito del tratamiento (AU)

Endodontic treatment of the first lower premolar when it has multiple ducts or multiple roots can be a challenge. This paper describes a clinical case of a 60-year-old male patient who attends the on-call service of the School of Dentistry of the University of Buenos Aires (FOUBA). Upon clinical and radiographic examination, the presence of two sinusal tracts that corresponded to the same dental piece with a diagnosis of chronic alveolar abscess was discovered. We conclude that the operator must carry out a thorough diagnosis and analyze and understand the different anatomical configurations in order to properly treat them, thus increasing the probability of treatment success (AU)

Brain activation patterns during unilateral premolar occlusion.

OBJECTIVE: To observe the characteristics of brain activation during unilateral premolar occlusion. METHODS: Functional magnetic resonance imaging was collected from 10 healthy volunteers during occlusion of the left first premolar (L1), left second premolar (L2), and right first premolar (R1). The brain activation patterns were analyzed, and the primary sensorimotor cortex, supplementary motor area, insula, thalamus, and prefrontal cortex were chosen as regions of interest. RESULTS: Single premolar occlusion activated the precentral gyrus, postcentral gyrus, cerebellum, thalamus, frontal lobe, hippocampus, cingulate gyrus, and parietal lobe. The brain areas showing activation during single premolar occlusion were similar to those activated by chewing. The activation pattern of L1 was more similar to that of L2 than R1. No significant left and right hemisphere differences in signal intensity were detected within the regions of interest. CONCLUSION: Brain activation patterns from two ipsilateral premolars were more similar than the pattern from a contralateral premolar.

The extent of root resorption and tooth movement following the application of ascending and descending magnetic forces: a prospective split mouth, microcomputed-tomography study.

OBJECTIVE: Various factors have been examined in the literature in an attempt to reduce the incidence and severity of root resorption. The purpose of the present investigation is to test the null hypothesis that there is no difference in relation to force level using gradually increasing (ascending) and decreasing (descending) orthodontic force generated by magnets on the severity of Orthodontically Induced Inflammatory Iatrogenic Root Resorption (OIIRR) and amount of tooth movement. METHODS: Twenty maxillary first premolars from 10 patients were subjected to ascending (25-225 g, magnets in attraction) and descending (225 to 25 g, magnets in repulsion) buccal forces using a split mouth design over an 8-week period. Polyvinyl siloxane impressions were taken at week 0, 4, and 8 to record the tooth movement. After 8 weeks, the teeth were extracted, scanned, with micro-CT in 16.9 µm resolution, and the root resorption craters were localized circumferentially and quantified at each level of the root. RESULTS: The total volume of OIIRR with ascending force was 1.20 mm3, and with descending force was 1.25 mm3, and there was no statistically significant difference between them. OIIRR on the palatal surface (0.012 mm3) was significantly less than on the buccal surface (0.057 mm3) and than on the mesial surface (0.035 mm3). There is no statistically significant difference in the degree of OIIRR between different level of the root (cervical, middle, and apical) at different surfaces. Moreover, the amount of tooth movement, at 0-, 4-, and 8-week interval, secondary to an ascending and descending force application was not statistically significant. CONCLUSIONS: There is no short-term (8 weeks) statistically significant difference between orthodontic ascending and descending forces, from 25 to 225 g and from 225 to 25 g, respectively, in term of severity and location of OIIRR as well as the amount of tooth movement. The buccal surface of the root showed highest degree of OIIRR compared to other root's surfaces.

Artefact expression associated with several cone-beam computed tomographic machines when imaging root filled teeth.

AIM: To evaluate the characteristic artefact patterns associated with teeth root filled with Gutta-percha when scanned with four cone-beam CT devices. METHODOLOGY: Whilst using soft tissue simulation, ten root filled human premolars were placed in empty sockets in a dry human skull. Subsequently, the skull was scanned using 3D Accuitomo 170(®) , WhiteFox(®) , Cranex 3D(®) and Scanora 3D(®) following clinical protocols with the highest resolution and artefact reduction. After proper image registration in OnDemand3D(®) software (Cybermed, Seoul, Korea), each image slice was evaluated by three trained and calibrated dentomaxillofacial radiologists, which scored absence (0) and presence (1) of cupping artefact, hypodense halos and streak artefacts. Kappa test was performed for intra- and interobserver agreement. RESULTS: A moderate to perfect agreement for each observer (intra-observer κ = 0.5-1.0) was found. Agreement between the different observers was moderate to almost perfect for the different artefact patterns (interobserver κ = 0.55-0.9). Cupping artefact was the most prevalent (70%), followed by a hypodense halo (35%) and streak artefacts (16%). The Chi-squared test revealed significantly more streaks in axial slices (P < 0.0001), with some CBCT systems yielding significantly inferior results to others (P < 0.05). The dedicated EndoMode and artefact reduction did not improve the result significantly. CONCLUSIONS: The variation of artefact expression was significantly different amongst CBCT machines for root filled teeth. Continuous efforts are needed to improve CBCT reconstruction algorithms, with a specific focus on reducing artefacts induced by dense dental materials, whilst striving for enhanced image quality at low-radiation doses.

Manejo endodóntico de un primer premolar maxilar con tres raíces / Endodontic management of a three-rooted maxillary first premolar

Objetivo: informar el manejo endodóntico de un primer premolar maxilar con tres raíces, mediante tratamiento de conductos adecuado a estos casos. Caso clínico: un paciente de sexo femenino, de 25 años de edad, se presentó a la consulta con un diagnóstico de pulpitis irreversible asintomática en la pieza 14. A partir de los hallazgos clínicos y radiográficos iniciales -que hacían sospechar una alteración en el número de conductos-, se comprobó la presencia de tres conductos radiculares. Esta situación obligó a realizar el tratamiento endodóntico con cuidados específicos para localizar todos los conductos radiculares y prevenir desgastes excesivos y/o perforaciones. Conclusión: el diagnóstico oportuno de esta variación anatómica permite establecer modificaciones en el protocolo del tratamiento de conductos, a fin de evitar el debilitamiento excesivo o, incluso, la perforación de su estrecha anatomía radicular (AU)

Accuracy of electronic apex locator in enlarged root canals with different root canal irrigants: an in vitro study.

AIM: To evaluate the accuracy of Root ZX-II (J Morita Corp) apex locator in enlarged root canals with different root canal irrigants. MATERIALS AND METHODS: 48 freshly extracted single rooted mandibular premolar teeth were used. The apical enlargement was done up to #45 K-file as the master apical file (MAF). The teeth were randomly divided into 4 groups and mounted in an experimental apparatus. The following irrigants were used during electronic canal measurements: group 1: saline; group 2: 3% NaOCl; group 3: 2% chlorhexidine; group 4: 17% EDTA. The canal measurement was done with Root ZX-II apex locator using #10 and #45 K-file. Data were analyzed by two way ANOVA and Bonferroni multiple comparison test. RESULTS: Statistical analysis showed that there was statistically significant difference between #10 and #45 K-file for group 1 (p < 0.01). CONCLUSION: Root ZX-II was accurate in the presence of 3% NaOCl and 17% EDTA when measured with smaller and larger files. However, it was accurate in the presence of saline and 2% CHX when larger files were used.

Should pulp chamber pulpotomy be seen as a permanent treatment? Some preliminary thoughts.

AIM: To investigate the benefits of pulpotomy (to the level of the floor of the pulp chamber) as an endodontic treatment for teeth with vital pulps. METHODOLOGY: Seventeen patients, aged 7-54 years (mean of 37.2 year), were treated by pulpotomy and filling with ProRoot MTA(®) in premolar or molar teeth with vital pulps and without clinical evidence of irreversible pulpitis. The patients were then followed up for 12 to 24 months and the teeth then assessed by clinical and radiographic examination. Statistical analysis was performed with Kaplan-Meier survival probability statistics to estimate the survival of the treated teeth. RESULTS: At 24 months, the survival rate without any complementary treatment was estimated to be 82%. Two of the 17 treated teeth required root canal treatment for pain control and one for prosthetic reasons. CONCLUSIONS: Under the conditions of this study, pulpotomy offered a viable alternative to root canal treatment for teeth with vital pulps in the short term. However, there is insufficient clinical evidence to consider this technique for the treatment of every permanent tooth. Nevertheless, it should be considered as a potential alternative approach to be further developed for future applications.

Comprehensive gene expression analysis in human periodontal ligaments of the mandibular third molars performing vertical movement and the maxillary second premolars with occlusal contact.

OBJECTIVES: The periodontal ligament (PDL) is thought to be an important tissue in vertical movement during tooth eruption, but the precise molecular mechanism is not known. Thereto, comprehensive gene expression was analyzed in human PDL of mandibular third molars performing vertical movement and maxillary second premolars with occlusal contact. DESIGN: The expression profile of 9,243 genes in the PDL of one subject was compared between vertically moving third molars and second premolars with occlusal contact by DNA microarray. RESULTS: The expression of 27 genes showed more than a 10-fold difference between third molars and second premolars. The expression of CALB1 (encoding calbindin 1), CYP26A1 (encoding cytochrome P450, family 26, subfamily A, polypeptide 1), SPOCK3 (encoding testican-3), CCK (encoding cholecystokinin) and SCRG1 (encoding scrapie responsive protein 1) was more than 30-fold higher in PDLs of the third molars than the second premolars. CALB1 is reported to increase at the pressure side of PDL during experimental orthodontic tooth movement in rats. Interestingly, in this study, CALB1 expression showed the largest difference. In contrast, CRCT1 (encoding cysteine-rich C-terminal 1), SPRP3 (encoding small proline-rich protein 3), IL8 (encoding interleukin 8) and MMP12 (encoding matrix metalloproteinase 12) showed more than 100-fold higher expression in PDLs of the second premolars than the third molars. CONCLUSION: The present comprehensive gene expression in PDLs provides new insights into the molecular mechanism during the vertical tooth movement.

Uncommon radiological findings: a case report.

A 50-year-old friendly and attractive Chinese lady was examined by the Primary Care Unit, Faculty of Dentistry, University of Malaya. Her requests for treatment included implants and crowns. Two periapical radiographs of teeth 16 and 48 were taken to aid diagnosis. Interestingly, pin-like radio-opaque objects were found over the crown of the impacted tooth 15 and also tooth 17. These objects were initially interpreted as silver points or radiographic artifacts but further investigation employing panoramic radiography revealed the distribution of more radio-opaque objects in the orofacial region. Based on a review of the literature and the opinion of experienced radiology and oral surgery lecturers, these foreign radio-opaque objects were diagnosed as susuks or charm needles.

Correlation between buccolingual inclination and wear of mandibular teeth in ancient and modern Japanese.

This study compared the correlation between the buccolingual inclination and the wear score of the mandibular teeth in Jomon (one of the ancestors of modern Japanese who lived from 5000 to 300 BC) and modern Japanese. Data were obtained from 40 modern male Japanese and 39 male Jomon skulls housed in the University Museum of the University of Tokyo and National Science Museum, Tokyo. For each specimen, three computed tomograms of coronal sections of the mandibular body were available. The second premolar, first molar and second molar of Jomon stood more vertically than those of modern Japanese. There were significant correlations between tooth wear and the buccolingual inclination of mandibular molars. When ancient and modern populations were compared, tooth wear was significantly greater and buccolingual tooth inclination was more vertical in the ancient people, who probably applied stronger masticatory forces than modern people. The results suggest that the mandibular molar orientation is more buccal and there is greater tooth wear in the first and second molars of people with strong masticatory function.