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At least 595 records · Page 33Linked to original sources
PubMed2005

Assemblages of ericoid mycorrhizal and other root-associated fungi from Epacris pulchella (Ericaceae) as determined by culturing and direct DNA extraction from roots.

Ericoid mycorrhizal fungal endophytes form mycorrhizal associations with Ericaceae plant taxa and are regarded as essential to the ecological fitness of the plants in extremely nutrient-poor soils worldwide. We isolated fungi from roots of Epacris pulchella (Ericaceae) in a south-eastern Australian sclerophyll forest and compared rDNA internal transcribed spacer (ITS) restriction fragment length polymorphisms (RFLPs) and sequences for the cultured isolate assemblage with fungi identified in DNA extracted directly from the same root systems by cloning or denaturing gradient gel electrophoresis (DGGE). The most abundant RFLP types in the cultured isolate assemblage were identified as putative ericoid mycorrhizal ascomycete endophytes, and these also represented the most abundant RFLP types in the cloned assemblage and the most intense bands in DGGE profiles. Each method identified unique taxa, notably putative basidiomycetes in the DNA extracted directly from E. pulchella roots. However, the relative abundance of these was low.

DNA, Fungal↗
PubMed1976

Root fractures in permanent anterior teeth with incomplete root formation.

A follow-up study was made of seven teeth with incomplete root formation observed in a group of 66 permanent teeth with root fracture. Three fractures were overlooked on the initial radiographs, two other teeth were suspected of being fractured, and an accurate diagnosis was made in two cases only. All teeth exhibited markedly increased mobility at the initial examination, and slight dislocation of the coronal fragment was found in two teeth. Following reduction (two teeth) and fixation (all teeth), the observation period ranged from 1 1/2 to 19 years. Retained pulp vitality, repair in the fracture area and, most important, approximately normal root development with closure of the apical foramen were observed in all teeth. Even the occurrence of re-fracture in two semmingly repaired teeth did not jeopardize the long-term result.

Child↗
PubMed1992

Efficacy of different irrigation methods and concentrations of root canal irrigation solutions on bacteria in the root canal.

The effectiveness of two different root canal irrigating solutions, each in two different concentrations or formulations, with two different irrigation methods was compared in vitro by means of bacterial survival determinations. 75 human root canals were enlarged, sterilized and inoculated with a mixed culture of Escherichia coli and Streptococcus mutans. After inoculation, the root canals were irrigated either manually or with an ultrasonic device for equal times (20s) with the same amount (5 ml) of sodium hypochlorite (1% and 2%), Fokalhydran I and Fokalhydran II. Sodium hypochlorite (1% and 2%) was used in a 1:100 dilution. Fokalhydran I and II were used in a 1:10 dilution. In the sodium hypochlorite group, the 1% concentration applied with a syringe proved to be most effective against Escherichia coli and Streptococcus mutans. The least effective concentration and application method against both bacteria species was obtained with 2% NaOCL and ultrasonics. Against Escherichia coli and Streptococcus mutans, a significantly lower effectiveness was found with 2% NaOCL applied with ultrasonics with respect to the rest of the sodium hypochlorite group. Fokalhydran I was significantly better than Fokalhydran II against Escherichia coli. However, no significant differences could be seen against Streptococcus mutans within this group.

Analysis of Variance↗
PubMed1983

Anatomic topographical relationship of the intraspinal accessory root to the upper cervical roots and to the vessels of the cranial cervical region.

The object of this investigation was to provide a statistical interpretation of macroscopic anatomic findings in the cranial cervical region, which is very rich in variation. In this way rare nervous and vascular variations could be related statistically. The first cervical posterior root demonstrated the most striking variations, which, according to anlage and connection with the accessory nerve, was divided into four anlage types of formation. In this way it was shown that in only 23% of the cases, no posterior C-1 root had been formed. It was further demonstrable that in at least part of the cases the accessory nerve was sensibly mixed with the first posterior root. Furthermore, nervous structures and peculiarities in the vessels were investigated. Special courses taken by the posterior inferior cerebellar artery, in addition to those already known, were statistically interpreted. Nervous as well as vascular contact and courses were analyzed, especially in relation to their topography to the accessory nerve, in order to provide clinicians with possibilities for explanations of irritations or compressions of this cranial nerve.

Arteries↗
PubMed2006

Root canal system in the mesiobuccal root of the maxillary first molar: an in vitro comparison study of computed tomography and histology.

OBJECTIVES: The purpose of this study was to investigate a new diagnostic approach to the examination of the canal configuration of the mesiobuccal root of the maxillary first molar. MATERIALS AND METHODS: High-resolution computed tomography (CT) was compared with histology in vitro. There were 152 teeth investigated and classified according to Weine and Vertucci. RESULTS: CT describes the exact canal configuration, verifying information identical to histology, and thus serving as the "gold standard" in vitro. With regard to canal position, 9 (5.92%) of the teeth examined were Vertucci type 1, 48 (31.58%) were Vertucci type 2, 91 (59.87%) were Vertucci type 4, 1 (0.66%) was Vertucci type 5, 1 (0.66%) was Vertucci type 6. Of the 152 teeth examined, 3 (1.97%) could not be classified using Weine, 2 (1.31%) could not be classified according to either Weine or Vertucci, and no Vertucci types 3, 7 or 8 were identified. CONCLUSIONS: CT offers complete information on the number and configuration of root canals. As the root canal configuration of the adult does not change rapidly, CT investigations can be used for multiple subsequent treatments.

Adult↗
PubMed1997

Reduction in amplitude of the ventral root elicited small spike by dorsal root stimulation in cat motoneurons.

Ventral root stimulation is known to produce two spikes, large and small, in the alpha-motoneuron. Since it is the small spike that triggers the outgoing impulse from the cell it is regarded as the key potential in information processing of the cell and referred to either as the IS-spike or as the A-spike depending upon whether one considers it as a purely single spike or as a composite spike. The small spike was elicited by stimulating the L 7 or S 1 ventral root in cats anesthetized with pentobarbital sodium and immobilized with d-tubocurarine. During the later phase of the excitatory prostsynaptic potential and thereto following inhibitory postsynaptic potential (IPSP) produced by stimulating the corresponding dorsal root the amplitude of the small spike was reduced by about 20%. This could be either explained as due to reduction in impedance of the membrane generating the small spike or interpreted as suggesting that the small spike is a composite spike and some of its components were inhibited by the IPSP. This interpretation was favored because the reduction occurred not when the safety factor for antidromic impulse transmission was high, but when it was low.

Action Potentials↗
PubMed1989

Scaling and root planing effectiveness: the effect of root surface access and operator experience.

This study investigated two variables associated with scaling and planning (S&RP): operator experience level and root surface access. One hundred and fourteen periodontally involved, single-rooted teeth designated for extraction were randomly distributed among four operators of various experience levels for either an open or closed session of S&RP. Immediately after treatment, the teeth were extracted, washed, and scored for residual calculus in a blind manner. Results showed that there was no difference in S&RP effectiveness for experience level or type of procedure in shallow (1-3 mm) pockets. However, in moderate (4-6 mm) and deep (greater than 6 mm) periodontal pockets, S&RP combined with an open flap procedure was more effective than S&RP alone for both experience levels. Also, the more experienced operators produced a significantly greater number of calculus-free root surfaces than the less experienced operators in periodontal pockets with moderate and deep probing depths. Clinical application of these results suggests that surgical access is associated with thorough surface debridement in periodontal pockets with moderate-to-advanced probing depths. However, more experienced operators could be expected to render more effective soft surface debridement.

Adult↗
PubMed1997

Tetracycline fibers plus scaling and root planing versus scaling and root planing alone: similar results after 5 years.

This paper presents 5-year data pertaining to a subgroup of patients from a previous investigation who were treated with scaling and root planing plus tetracycline fibers. The parent study demonstrated that 6 months after therapy, scaling and root planing plus tetracycline fiber therapy was significantly better at reducing probing depth and gaining clinical attachment than scaling and root planing alone. However, the long-term data presented here show a regression from the original gains in clinical attachment levels in the fiber group. Ultimately, the use of fibers provided no significant advantage with regards to probing depth reduction or clinical attachment gain. Within the power of this study, which would have required 1.78 mm of change in clinical attachment to show a difference, there was no significant difference between the treatments at 5 years. This study underscores the need for additional long-term evaluation of this mode of therapy.

Analysis of Variance↗
PubMed2000

Spinal nerve root repair and reimplantation of avulsed ventral roots into the spinal cord after brachial plexus injury.

OBJECT: The authors review the first series of 10 cases in which injured intraspinal brachial plexus were surgically repaired. They describe the technique of spinal cord implantation or repair of ruptured nerve roots, as well as patient outcome. METHODS: Spinal root repair/implantation was performed from 10 days to 9 months postinjury. There were nine male patients and one female patient. Postoperatively in most cases, regeneration of motor neurons from the spinal cord to denervated muscles could be demonstrated. The first signs of regeneration were noted approximately 9 to 12 months postoperatively. Useful function with muscle power of at least Medical Research Council Grade 3 occurred in three of 10 cases. Magnetic brain stimulation studies revealed a normal amplitude and latency from the cortex to reinnervated muscles on surgically treated and control sides. A certain degree of cocontraction between antagonistic muscles (for example, biceps-triceps) compromised function. With time there was a reduction of cocontractions, probably due to spinal cord plasticity. In these cases there was also, surprisingly, a return of sensory function, although the mechanism by which this occurred is uncertain. Sensory stimulation (thermal and mechanical) within the avulsed dermatomes was perceived abnormally and/or experienced at remote sites. There was some return of patients' sense of joint position. CONCLUSIONS: A short time lag between the accident and the surgery was recognized as a significant factor for a successful outcome. Reimplantation of avulsed nerve roots may be combined with other procedures such as nerve transfers in severe cases of brachial plexus injury.

Adult↗
PubMed2001

Effectiveness of the ProFile.04 Taper Series 29 files in removal of gutta-percha root fillings during curved root canal retreatment.

The purpose of this in vitro study was to evaluate the capacity of ProFile.04 Taper Series 29 files to remove gutta-percha during curved root canal retreatment. Forty-four mandibular molars whose mesial roots presented between 26 and 40 degrees of curvature, determined by Schneider's method, were selected. The root canals were enlarged to ISO size 35 and obturated with laterally condensed gutta-percha using Sealer 26. The teeth were randomly divided into three groups for gutta-percha removal: GI: size 2 Gates Glidden drills; GII: size 6 ProFile.04 Taper Series 29 files; GIII: size 7 ProFile.04 Taper Series 29 files. The penetration of the instruments was measured with millimetered x-rays and clinical observation. The ProFile.04 Taper Series 29 files removed the endodontic filling material better than the Gates Glidden files.

Analysis of Variance↗
PubMed2000

[The influence of different root length on stress distribution in the bone around abutment root of telescopic overdenture].

OBJECTIVE: To investigate the influence of bone height around the roots on stress distribution in a mandible with two canines remained and covered with an telescopic overdenture. METHODS: Three-dimensional finite element method. RESULTS: As the height of the bone around the roots decreased, the stress increased. But the maximum stress in the bone in this study is lower than that in the bone around the canine under normal condition. CONCLUSION: In the mandible, when the alveolar bone resorption reaches the apical 1/3 of canine (root length 4, 5 mm), if part of the tooth crown was removed, to make an acceptable crown/root ratio, so the canine can be used as the abutment of an overdenture.

Compressive Strength↗
PubMed2003

Root resorption associated with a subepithelial connective tissue graft for root coverage: clinical and histologic report of a case.

This article reports on a case of root resorption following a clinically successful root coverage procedure with a subepithelial connective tissue graft on a maxillary lateral incisor. Two years after the graft procedure was performed, the tooth was extracted in conjunction with the buccal attachment apparatus. Histologic examination of the specimen revealed signs of active resorption of the dentinal surface and bone formation in the deepest portion of the resorption cavity. Possible causative factors of the root resorption process are discussed.

Connective Tissue↗
PubMed2004

[The effect of left bacteria in the root canal on prognosis of the root canal therapy].

OBJECTIVE: To study the effect of the left bacteria on the root canal therapy. METHODS: 50 single-rooted teeth with chronic apical periodontitis were divided into two groups, one was instrumented with step-back technique and 2.5%NaOCl ultrasonic irrigation for 3 min, then filled with Thermafil. Samples were taken after instrumentation to culture. The other was treated with traditional RCT at three visits. RESULTS: In 24 months the apical radiolucency were greatly reduced in all cases. There weren't significant relationship among the postoperative pain and the left bacteria, the degree of the obturation or the pre-operative symptoms (P > 0.05). CONCLUSION: The effect of left bacteria in root canal filled with Thermafil wasn't observed.

Adolescent↗
PubMed2004

[Effects of lanthanum on root membrane permeability and nutrient contents in root exudate of rice].

This study showed that when lanthanum was in lower concentration (< or = 50 microg x ml(-1)), the membrane permeability of rice root was stabilized by decreasing the electrolyte exosmosis, and the contents of K+, Ca2+, P and H+ in root exudate were lower than the control; while the concentration of La3+ was in the range of 100-400 microg x ml(-1), the electrolyte exosmosis was reduced in the first 6 hours, and then significantly increased. When the concentration of La3+ was over 500 microg x ml(-1), the electrolyte exosmosis was continuously enlarged because of the destruction of the membrane. Under this condition, K+, Ca2+, P and H+ in root exudate were higher than the control. It could be concluded that the concentration of 50 microg x ml(-1) La3+ was safe to rice growing.

Calcium↗
PubMed2004

[Ultrastructure of root cup meristematic cells of Cucumis sativus L. seedlings under inhibition of root growth by synthetic cyclopentene beta,beta'-triketone].

A study was made of the ultrastructure of root cap meristematic cells in the seedlings of Cucumis sativus L., whose growth was inhibited by the action of 2-acetyl-4-metylcyclopent-4-en-1,3-dione (AMCD). It is shown that the treatment of seeds by this substance at a concentration of 100 microg/ml leads to the main root inhibition by 73% and, as compared to the control, causes the highest changes in mitochondria that do not reach normal dimensions and undergo degeneration. AMCD caused significant changes in the cell walls that in test samples unusually became electron-dense. Deposits of osmiophylic substance, presumably consisting of terpenoid-like compounds, were often found in the cytoplasm of treated cells as well as in the extracellular space. In many cells, plasmalemma and amiloplast membranes underwent destructive changes. We discuss a possible relation between inhibitory effect of AMCD on the root growth, and its influence on the ultrastructure in investigated cells.

Cucumis sativus↗
PubMed1991

Transcutaneous magnetic and electrical stimulation over the cervical spine: excitation of plexus roots-rather than spinal roots.

Percutaneous magnetic stimulation (MagStim) and electrical stimulation (ElStim) over the cervical spine were performed in 65 subjects. Compound muscle action potentials (CMAPs) from the abductor digiti minimi (ADM) and the biceps muscles (BICEPS) could be recorded in all subjects tested with both, ElStim and MagStim. Maximal stimulation as determined from the amplitudes of CMAPs was possible in most cases with ElStim but not with MagStim. Latencies after MagStim (centered over C7) and ElStim (cathode over C7/T1, anode positioned 6 cm cephalad in the midline) were not statistically significantly different (P = 0.3). However, in the individual case, it was difficult to predict the precise site at which the motor roots would be activated, since latencies of CMAPs to ElStim and MagStim could differ by up to 1.2 msec. In addition, the excitation site migrated distally when the stimulation intensity was increased with the aim to obtain CMAPs of nearly maximal amplitudes. The results of studying brachial plexus stimulation as well in 22 of the subjects led us to the conclusion that excitation of the motor roots occurs on the average 7 cm (range: 1.4-8.2 cm) proximally to Erb's point. This was confirmed by the finding that when the C7 motor root was stimulated directly intraoperatively within the intervertebral foramen, the excitation site was calculated to be 7.7 cm distal to the foramen and 8.4 cm proximal to Erb's point.

Action Potentials↗
PubMed1989

[Apical root pins of high-karat gold alloys for resected roots].

Following earlier studies on corrosion of silver pins in the root canal experience will be presented with the use of high-karat gold pins for apical closure of root amputations. The commercially available standardized Ackermann silver pins were replaced by high-karat gold pins of similar Vicker hardness and inserted in 218 patients with 264 root amputations since 1986. A clinical and radiological follow-up demonstrated a success rate of over 90%.

Dental Pins↗
PubMed1989

[Temperature determination of root surfaces in manual and mechanical preparation of root canals].

In in vitro studies it was determined which temperatures develop on the root surface using different root canal preparation techniques. 62 teeth were filed manually, by conventional mechanic technique and by ultrasonic driven instruments. Practicing manual and mechanic filing critical temperatures for the cell structures of the desmodont did not develop. Ultrasonic and ultrasonic--like instruments, however, develop high temperatures on the root surface so that the cooling effect of the irrigation liquid after each instrumentation is not sufficient and a continuous irrigation during filing is indicated.

Hot Temperature↗