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Effect of wavelength and bandwidth on the clinical reliability of laser Doppler recordings.

The aim of this study was to investigate the effect of wavelength and bandwidth on laser Doppler flowmeter signals from vital and root-filled teeth, and to establish their sensitivity and specificity. Twenty human subjects were recruited, each with a vital tooth and the contralateral tooth root filled but not restored apart from the palatal access cavity. Readings were taken from these teeth for 3 min at 20 Hz for each of 3.1 kHz, 14.9 kHz and 22.1 kHz bandwidths using a modified laser Doppler blood flow monitor which permitted simultaneous recording using 810 nm and 633 nm light sources with a probe of four optical fibres with 0.25 mm separation. Ten traces from each combination of variables was examined by 10 trained observers who indicated if the traces came from vital or root-filled teeth judged by the amplitude and regularity of pulsatility of the trace. From the accuracy of their replies, sensitivity and specificity were calculated. Median flux values were higher for vital teeth than for root-filled teeth and for the 810 nm wavelength than for the 633 nm wavelength. Flux values increased with wider bandwidth using the 810 nm light source. With the 633 nm light source, the highest flux values were recorded using the 3.1 kHz bandwidth. Using the Mann-Whitney U test, there was a highly significant difference between readings from vital and root-filled teeth for the 3.1 kHz/810 nm wave length combination (p<0.003) and a significant difference for the 3.1 kHz/633 nm wavelength group (p<0.02). Comparison of other groups showed no significant difference (p>0.05). The 810 nm wavelength showed good sensitivity but poor specificity at 14.9 and 22.1 kHz bandwidths. The 633 nm wavelength showed good specificity, but poor sensitivity, at 14.9 and 22.1 kHz bandwidths. The 3.1 kHz bandwidth showed the best sensitivity and specificity for both wavelengths. Sensitivity and specificity were increased if the results of fast Fourier analysis were considered in addition to observations of flux values and pulsatility of traces. The 810 nm/3.1 kHz combination offered the greatest sensitivity and specificity as a test to distinguish between root-filled and vital teeth. This combination was best when the results of Fourier analysis were considered in addition to visual observations.

Artifacts↗

Effect of thermocycling on the retention of glass-fiber root canal posts.

OBJECTIVE: This study investigated the effects of thermocycling on the retention of glass-fiber and resin posts. METHOD AND MATERIALS: Forty premolar and canine tooth roots were embedded in acrylic blocks shaped to fit into a retention device. The roots were randomly assigned to two groups of 20 to receive either Lightposts or Luscent Anchors which were cemented into 9-mm-deep post spaces, with Panavia F resin cement. Each group was randomly divided into two equal subgroups: one for thermocycling, and the other to serve as a control. The thermocycled specimens were cycled 3,000 times between water baths at 5 degrees C and 55 degrees C, with a dwell time of 60 seconds in each. Control specimens were stored at 37 degrees C. The tensile force required to dislodge each post from its root was recorded and the data analyzed using Student's t tests. RESULTS: There were no significant differences in the forces required to cause post-retention failure between the control and thermocycled specimens. Lightposts were significantly more retentive than Luscent Anchors without thermocycling, but this distinction was not apparent in the thermocycled groups. CONCLUSION: Glass-fiber and resin posts cemented with resin cement offer acceptable levels of retention and are not susceptible to reduced retention from thermocycling. Thermocycling should be given less emphasis in tests for the retention of root canal posts cemented with resin cements.

Bicuspid↗

The fundamental operating principles of electronic root canal length measurement devices.

It is generally accepted that root canal treatment procedures should be confined within the root canal system. To achieve this objective the canal terminus must be detected accurately during canal preparation and precise control of working length during the process must be maintained. Several techniques have been used for determining the apical canal terminus including electronic methods. However, the fundamental electronic operating principles and classification of the electronic devices used in this method are often unknown and a matter of controversy. The basic assumption with all electronic length measuring devices is that human tissues have certain characteristics that can be modelled by a combination of electrical components. Therefore, by measuring the electrical properties of the model, such as resistance and impedance, it should be possible to detect the canal terminus. The root canal system is surrounded by dentine and cementum that are insulators to electrical current. At the minor apical foramen, however, there is a small hole in which conductive materials within the canal space (tissue, fluid) are electrically connected to the periodontal ligament that is itself a conductor of electric current. Thus, dentine, along with tissue and fluid inside the canal, forms a resistor, the value of which depends on their dimensions, and their inherent resistivity. When an endodontic file penetrates inside the canal and approaches the minor apical foramen, the resistance between the endodontic file and the foramen decreases, because the effective length of the resistive material (dentine, tissue, fluid) decreases. As well as resistive properties, the structure of the tooth root has capacitive characteristics. Therefore, various electronic methods have been developed that use a variety of other principles to detect the canal terminus. Whilst the simplest devices measure resistance, other devices measure impedance using either high frequency, two frequencies, or multiple frequencies. In addition, some systems use low frequency oscillation and/or a voltage gradient method to detect the canal terminus. The aim of this review was to clarify the fundamental operating principles of the different types of electronic systems that claim to measure canal length.

Dental Pulp Cavity↗

The influence of tooth wear on root canal dimensions.

The objective was to investigate the relations between tooth wear and root canal dimensions. The experimental group comprised 100 cuspids (canines), 50 of which had advanced abrasion and 50 were without it The dimensions of root canal were investigated at the light microscope level in order to define their vestibulo-oral and mesio-distal diameters in all three thirds. In the groups of teeth without abrasion the MD diameters of root canaliculi in their cervical thirds were greater than in the teeth with advanced abrasion. In the apical third the MD diameters of canaliculi were highly variable in teeth with no signs of abrasion. In the group of teeth with abrasion the MD and VO diameter values of the cervical thirds were significantly smaller than in the group of teeth without abrasion. In the mid-thirds the values of MD diameters were highly variable in the group of teeth with abrasion, whereas the VO diameter values were much greater than in the teeth without abrasion. As regards to the apical thirds, the VO diameter values were greater than in the control teeth. The data presented herewith contribute to better knowledge about tooth wear and are highly useful in restorative and reconstructive dental procedures.

Cuspid↗

Loss of tooth substance during root planing with various periodontal instruments: an in vitro study.

Ultrasonic and power-driven instrumentation is gaining in significance as an acceptable alternative to manual periodontal root treatment. Some question whether they do not remove too much tooth substance. Various ultrasonic scalers, hand instruments and two power-driven systems were compared by assessing the loss of tooth substance due to root instrumentation. Quantitative analysis of this effect of the instruments used was performed on 20 freshly extracted, non-periodontally involved, large human molars. In the first study, 40 specimens were randomly assigned to four groups of treatment: combined use of ultrasonic scaler and Periopolisher diamond-coated inserts (US-POL), hand instruments (MANUAL), Perioplaner-Periopolisher system (PPL-POL) and Periokit ultrasonic-designed scalers (PERIOKIT). The second study involved two treatment groups, ultrasonic scaler alone and hand instruments, each allocated with 20 teeth (small root fragments). An unpaired two-tailed t test was carried out for both studies to compare the average weight loss of root substance with the modes of instrumentation. The level of significance was set at p<or=0.05. The overall results of the first and second experimental trials did not reveal obvious differences in weight loss between the manual, ultrasonic or power-driven root treatments. Based on the results of these two comparative studies, the power-driven inserts or the various ultrasonic scalers tested did not remove more tooth substance than conventional hand instruments. They may thus be a useful alternative for the debridement of root surfaces.

Dental Scaling↗

Gingival crevicular fluid monocyte chemoattractant protein-1 and RANTES levels in patients with generalized aggressive periodontitis.

BACKGROUND: Local and systemic inflammatory and immune mechanisms may be implicated in the pathogenesis of the aggressive forms of periodontal disease. Chemokines, monocyte chemoattractant protein-1 (MCP-1) and regulated on activation, normal T cells expressed and secreted RANTES (regulated on activation, normal T cells expressed and secreted), are involved in the activation and recruitment of inflammatory and immune cells to the infected sites and thereby mediating a variety of pathophysiological conditions. The aim of the present study was to examine the gingival crevicular fluid (GCF) levels of MCP-1 and RANTES in patients with generalized agressive periodontitis (G-AgP). METHODS: MCP-1 and RANTES levels were investigated in GCF samples of 10 patients with G-AgP and 10 periodontally healthy subjects. Periodontal status was evaluated by measuring probing depth, clinical attachment loss, presence of bleeding on probing and plaque. In the G-AgP group, GCF samples were collected from the two approximal sites; from one single-rooted tooth and from one first molar tooth with > or =6 mm probing depth. In the healthy group, GCF samples were collected from one of the single-rooted teeth. GCF MCP-1 and RANTES levels were quantified by enzyme immunoassay. RESULTS: The G-AgP patients had significantly higher GCF MCP-1 and RANTES levels compared to the healthy group (p<0.05). GCF MCP-1 and RANTES levels were positively correlated with both probing depth and clinical attachment loss (p<0.05). There was no correlation between GCF MCP-1 and RANTES levels and the percentage of sites with bleeding (p>0.05). CONCLUSIONS: The results of the present study suggest that MCP-1 and RANTES could play key roles in both activation and recruitment of inflammatory and immune cells in periodontal environment of G-AgP patients. In conclusion, these CC chemokines may be considered in the biological mechanism underlying the pathogenesis and progression of G-AgP.

Adolescent↗

Developing cementoblastoma: case report and update of differential diagnosis.

The benign cementoblastoma is a rare odontogenic tumor that tends to occur in the jaws of young people. It is most commonly characterized as a circumscribed radiopaque mass attached to the tooth roots and rimmed by a thin radiolucent zone. Early lesions, however, are radiolucent and can be confused with periapical conditions resulting from nonvital teeth. The tumor is seldom recognized until it produces pain or expansion of the jaw. If the diagnosis is established early, the tooth can be saved by endodontic treatment followed by apical root resection and surgical enucleation of the tumor. This case report documents the origin, development, and unlimited growth potential of a cementoblastoma. Radiographs taken at yearly intervals reveal an initial widening of the periodontal ligament space that grew into a 3-cm mixed radiolucent and radiopaque tumor over a 4-year period. The differential diagnosis and some criteria to help distinguish the cementoblastoma from similar-appearing lesions are reviewed.

Adolescent↗

Tooth morphology following root resection procedures in maxillary first molars.

The Disto-Buccal root is the most commonly resected root in maxillary molars. This root resection procedure results in a unique environment dictated by the contours of the remaining roots and the residual furcation between them. Tooth morphology was evaluated in 50 extracted maxillary first molars after disto-buccal root resection. The following measurements were studied: 1) The maximum concavity (D) on the distal aspect of the resected molar; 2) the minimum mesio-distal dimension (d) of tooth structure between the two remaining roots; 3) the width (s) of the residual interradicular septum; and 4) the distance (p) from the pulp chamber floor to the root separation on the distal aspect of the resected molar. The mean measurements were (D) = 2.47 mm, (d) = 3.67 mm, (s) = 3.33 mm and (p) = 2.70 mm. The value of (p) was equal to or less than 3 mm in 86% of the teeth; this means that the distance from the finish line to the interradicular osseous peak is less than 2.04 mm (average biologic width), if the finish line is placed on solid tooth structure about 1 mm below the pulp floor. Six percent of the resected molars had an overall topography easily amenable to periodontal maintenance and restorative procedures with (D) less than 2 mm, (d) greater than 3 mm, (s) greater than 3 mm, and (p) greater than 3 mm. Poor root anatomy of the remaining roots after removal of the disto-buccal root in maxillary first molars may be considered as a contraindication for root resection procedures. Unfortunately, this poor topography can be ascertained only during the surgery and after removal of the disto-buccal root.

Dental Pulp Cavity↗

Pustulosis palmaris et plantaris: the value of routine radiographic examinations in the detection of an infectious focus.

A three-year clinical material of 163 patients with pustulosis palmaris et plantaris is presented. The study was designed to assess the value of routine radiographic examinations of teeth, nasal sinuses and chest in the detection of an asymptomatic infectious focus. 66 patients underwent 151 examinations. Infectious lesions were found in the lungs of 0 of 53 examinations, inflammation in the nasal sinuses in 3 of 52 examinations (6%) , and abscesses at the teeth roots in 8 of 46 examinations (17%). The 3 patients with sinuitis had symptoms leading to the diagnosis. The root abscesses were all asymptomatic. Elimination of the infectious foci did not affect the course of the disease. The high incidence of asymptomatic tooth root abscesses is discussed. From studies on clinically healthy persons, similar results have been reported. It is concluded that routine radiographic examinations are of little or no value, possibly with the exception of the dental examination.

Abscess↗

Resolution of furcation bone loss associated with vital pulp tissue after nonsurgical root canal treatment of three-rooted mandibular molars: a case report of identical twins.

This case report demonstrates the simultaneous development of furcation bone loss in three-rooted tooth #30 with vital pulp tissue in identical twins. In the first report, resolution of furcal bone loss was seen after nonsurgical root canal treatment. In the second report, furcal bone loss resolved after non-surgical root canal treatment, and periodontal therapy reduced probing depths to maintainable levels.

Adolescent↗

Inhibitory effect of the topical administration of a bisphosphonate (risedronate) on root resorption incident to orthodontic tooth movement in rats.

Root resorption associated with tooth movement is an unsolved problem in orthodontics. If such root resorption could be prevented, it would be an important contribution toward reducing risk factors in orthodontic treatment. The purpose of this study was to examine the effects of the topical administration of a bisphosphonate, risedronate, which is known to be a potent blocker of bone resorption, on root resorption during tooth movement and on the repair of the resorbed root surface after tooth movement in rats. In the first experiment, both the right and left upper first molars were moved buccally with a standardized expansion spring under administration of risedronate. After day 7, extensive root resorption had occurred on the control side, and the area of root resorption reached a maximum on day 14. The topical administration of risedronate caused a significant and dose-dependent inhibition of root resorption after the orthodontic force was applied. In the second experiment, the right and left upper molars were first moved buccally for 3 weeks. Risedronate treatment began on the day the spring was removed. After the force was withdrawn, the resorbed root surfaces on both the control and risedronate-treated sides were gradually restored by apposition of repair cementum (cementoid). The topical administration of risedronate did not appear to inhibit the repair process of root resorption. These results suggest that the topical administration of risedronate may be useful in preventing root resorption of teeth during orthodontic treatment.

Administration, Topical↗

[Restoring ceramo-metal tooth by using self-made crown post-core in order to re-utilize the broken crown of the base tooth].

OBJECTIVE: To explore a new method and its clinical significance of restorative ceramo-metal by using a self-made crown post-core to reutilize the broken crown. METHODS: 18 teeth were restored with ceramo-metal tooth by using self-made crown post-core in order to preserve the old broken base tooth. The patients' own feelings and clinical effect were observed. RESULTS: Followed up for 1-3 years, 83.3% (15 teeth) of the patients were successful. Among the group one was failed because of bad condition of post and caused split of tooth root. The second failure was caused by uneven force by coherent paste uneven. The third failure was caused by tight biting force and caused the tooth broken. CONCLUSION: Restoring ceramo-metal tooth by using self-made crown post-core in order to re-utilize the broken crown of the base tooth is convenient and low cost and is suitable for basic hospitals.

Crowns↗

Effect of cuspid positioning in the cleft at the time of secondary alveolar bone grafting on eventual graft success.

This investigation was to determine the relationship between the success of secondary alveolar bone grafting and the position of the permanent cuspid relative to the cleft at the time of grafting. In this retrospective study utilizing periapical radiographs take on cleft patients to evaluate bone grafting results, the subjects were patients treated at the Lancaster Cleft Palate Clinic, a private institution specializing in the care of cleft patients. Sixty-seven patients (20 BCLP; 47 UCLP) were selected for this study based on availability of quality radiographs and a minimum of 6-month post-surgical follow-up. All patients underwent alveolar bone grafting (mean age, 10 years 7 months). Presurgical radiographs were taken within 3 months of the operation. Post-surgical radiographs were taken to evaluate the outcome of grafting (mean follow-up, 2 years 10 months). Radiographs were traced and digitized on a total of 86 cleft sites. Presurgically, a ratio was used to determine the amount of cuspid crown emerged through the alveolus into the cleft site relative to the anatomic cuspid-crown length. Post-surgically, ratios of bone support for the teeth mesial and distal to the cleft were established by dividing the amount of root covered by bone by the anatomic root length. Ratios expressing the height of alveolar crest relative to the cementoenamel junction (CEJ) of adjacent teeth and amount of alveolar notching relative to the mesial tooth root length were also evaluated. Linear regressions of each of the five ratios of graft outcome on the cuspid-eruption ratio were done. No significant correlations could be found between final graft success and the amount of cuspid crown exposed in the cleft at the time of grafting. Cuspid position could not be shown to be a significant factor in determining graft success.

Alveolar Process↗

External skeletal fixation in the management of equine mandibular fractures: 16 cases (1988-1998).

Fifty-three cases of equine mandibular fractures were managed surgically from 1988-1998, of which 16 (30%) were repaired by external skeletal fixation (ESF). Three surgical methods were utilised: transmandibular 4.76 or 6.35 mm Steinmann pins incorporated into fibreglass casting material or nonsterile dental acrylic (methyl methacrylate - MMA) bars reinforced with steel; transmandibular 9.6 mm self-tapping threaded pins +/- 4.76 or 6.35 mm Steinmann pins incorporated into MMA bars reinforced with steel; and 4.5 mm or 5.5 mm ASIF cortical bone screws incorporated into MMA bars reinforced with steel or a ventral MMA splint. Fourteen horses were presented to the hospital for fixator removal at an average of 56.2 days. At removal, fractures were stable and occlusion of incisor and cheek teeth was considered adequate. Complications of the procedure occurred in 3 horses. Two horses with persistent drainage and ring sequestra from pin tracts required curettage 4 or 5 months after ESF removal. A third horse required replacement of the original fibreglass ESF with MMA bars to regain access to open, infected wounds. Another horse required removal of the second premolar at the time of fixator removal because the tooth root had been damaged in the original injury. ESF for the surgical management of mandibular fractures in horses has produced good results, with incisive and cheek tooth alignment reestablished in all horses. Horses that were managed via ESF had a rapid return to full feed and did not require any supplementation via nasogastric tube or oesophagostomy to maintain bodyweight or hydration status.

Animals↗

Dental considerations in the sublabial trans-sphenoidal surgical approach to the pituitary gland.

The sublabial trans-sphenoidal approach for the ablation of pituitary tumors can cause denervation or pulp death of some of the anterior teeth. The problem results from the bone removal necessary for placement of the nasal retractor. When bone is removed close to the apices of the anterior teeth, root injury may occur. This complication may be avoided through preoperative evaluation of skeletal and dental morphology. This evaluation reveals the amount of bone between the tooth roots and the nasal floor and hence the ultimate access for the nasal retractor.

Adenoma↗