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PubMed1991

In vivo efficacy of various retrofills and of CO2 laser in apical surgery.

The purpose of the present study was to radiographically assess the efficacy of various retrofilling materials and of the use of CO2 laser in apical surgery. The mandibular premolars of six beagle dogs were infected, resulting in periapical lesions. Apical surgery was performed without root canal treatment. Amalgam with cavity varnish, glass ionomer cement and a lightcured composite resin were the retrofilling materials used. In half of the material CO2 laser was used on the root surface and the bone, for occlusion of the dentinal tubuli and sterilization. The healing following surgery was observed radiographically for six months. The highest success rate (89%) was found in the roots retrofilled with amalgam and varnish, and the lowest (60%) in those retrofilled with the composite resin. The difference between these groups was statistically significant. The success rate following retrofilling with glass ionomer cement was 69%, and was not significantly different from both the other groups. Under the conditions of this study, the use of CO2 laser during surgery did not affect the treatment results.

Animals↗
PubMed1991

Retrograde root filling with composite and a dentin-bonding agent. 1.

A method is described, by which retrograde root filling with a composite resin can be performed. The cavity design is a slightly concave dissection of the apical part of the root, which is treated with the bonding agent Gluma followed by an application of Retroplast. Retroplast is a chemically curable composite containing silver for radiopacity and aerosil to obtain a suitable consistency. Endodontically treated teeth with a eugenol-containing root canal sealer did not affect the strength of the bond between Retroplast and apical dentin. A tight seal between the composite and the cavity surface was observed by light and SEM microscopy, and histology of tissue surrounding fillings placed in monkeys revealed absence of inflammatory cells around the filling and a close contact between filling and fibroblasts with collagenous fibers. In some cases, cementum and Sharpey's fibers formed in contact with the filling. Fillings placed in humans performed successfully in most cases, and the main causes of failure were either inadequate hemostasis during filling, or root fracture unnoticed by the time of filling. The retrograde technique promises a new treatment principle, with a root canal effectively sealed and the periapical ligament restored after apicoectomy.

Adolescent↗
PubMed1991

Retrograde root filling with composite and a dentin-bonding agent. 2.

Investigations on retrograde root filling using a composite resin, Retroplast, bonded to the root surface with the dentin-bonding agent Gluma have been described. Here, detailed information is given about the surgical procedures. The aim was to obtain a thin retrograde composite filling on the root apex, made slightly concave, sealing the main root canal, accessory canals as well as dentinal tubules. Hemostasis was obtained primarily by applying 1% adrenaline and by using a needle suction tip, and care was taken not to damage the surrounding tissues by the various chemicals. The healing results, after up to 1 year, of 388 cases of various tooth types, treated with either retrograde composite or with amalgam were compared. The healing classification included four categories: 1) complete healing; 2) fibrous healing; 3) uncertain; and 4) failures. In the composite group, the healing rates were as follows: 74% showed complete healing, 4% fibrous healing, 15% uncertain, and 7% were failures. In the amalgam group, 59% showed complete healing, 3% fibrous healing, 30% uncertain, and 8% were failures. Complete healing occurred significantly more often after filling with Retroplast than after filling with amalgam (p less than 0.00005). Significantly fewer cases with complete healing occurred in lower front teeth in proportion to other tooth types. The number of immediate postoperative complications did not differ significantly between the composite and the amalgam groups.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1992

Toxic effects of various retrograde root filling materials on gingival fibroblasts and rat sarcoma cells.

The aim of this in vitro study was to evaluate the effect of amalgam, glass ionomer, composite and titanium on the growth of gingival fibroblasts (GF) and rat sarcoma cells (UMR) in vitro. The cells were either obtained from gingival biopsies taken during deliberation of unerupted canines (GF) or were of commercial origin (UMR). Equal numbers of cells were placed on culture dishes and incubated for a period of two weeks with the freshly prepared test materials. The cultures were photographed through a light microscope after 7 days incubation and finally counted after 14 days. It was shown that the proliferation of gingival fibroblasts was less disturbed by titanium, being approximately 96% of the control value (cell cultures without test particles), followed by composite, amalgam and glass ionomer (61%, 49% and 35% of the control value respectively). The number of UMR cells after 14 days incubation with the various materials was 76% of the control value with titanium, 12% with composite and 5% with both amalgam and glass ionomer. Inhibition of cell growth (UMR) around the test particles was most prominent around amalgam and glass ionomer, followed by composite and titanium. These effects were noted only with freshly prepared components however, so that the toxic reaction was less pronounced or minimal in a second incubation using the same particles sterilized in between. The results demonstrated that potential retrograde root filling materials have a variable toxic effect on gingival fibroblasts and rat sarcoma cells. The fact that the influence on proliferation disappeared when the test was performed with materials already tested once may be of clinical importance when estimating the biocompatibility in vivo.

Adolescent↗
PubMed1994

Antibacterial activity of potential retrograde root filling materials.

The antibacterial activity of potential retrograde root filling materials was assessed using the agar diffusion inhibitory test. A light-cured glass ionomer cement (Vitrebond) and three reinforced zinc oxide-eugenol cements (Kalzinol, IRM & ethoxybenzoic acid [EBA] cement) were compared with amalgam, a commonly used retrograde root filling material. Forty standardized pellets of each material were produced. Fresh, and materials aged for 1 week in sterile distilled water, were placed on blood agar plates inoculated with Streptococcus anginosus (milleri) or Enterococcus faecalis. At intervals of 3, 7 and 10 days, the presence and diameter of zones of inhibition were recorded. The diameter of the zones of inhibition increased with time for all materials, both fresh and aged. Vitrebond had the most pronounced antibacterial activity against both bacteria, producing the largest zone of inhibition, followed by Kalzinol. Amalgam had no measurable inhibitory effect whether aged or fresh, regardless of the period of exposure. There was no statistically significant difference in the response of the two bacteria. However, there were statistically significant differences between materials, period of exposure, and between fresh and aged materials (P < 0.001). Kalzinol, IRM and EBA cement were more antibacterial when aged than fresh, whilst Vitrebond was more active when fresh. Vitrebond was the only material for which the diameter of the zones of inhibition was reduced after ageing but it had the most pronounced antibacterial activity compared with the other materials. The antibacterial activity of the materials was ranked in the following order: Vitrebond > Kalzinol > (IRM = EBA cement) > amalgam.

Analysis of Variance↗
PubMed1994

Biological properties of IRM with the addition of hydroxyapatite as a retrograde root filling material.

The effect of adding 10% & 20% hydroxyapatite (HAP) on the antibacterial activity and cytotoxicity of IRM (Intermediate Restorative Material) when used as a retrograde root filling was compared with amalgam, a commonly used material. The antibacterial activity was assessed using the agar diffusion inhibitory test. Forty standardized pellets of each material were produced. Fresh materials, and materials aged for 1 week in sterile distilled water, were placed on blood agar plates inoculated with Streptococcus anginosus (milleri) or Enterococcus faecalis. The presence and diameter of zones of inhibition were recorded at intervals of 3, 7 and 10 days. There was no statistically significant overall difference in the response of the two bacteria tested. However, there were statistically significant overall differences in diameters of the zones of inhibition related to different materials, period of exposure and ageing of materials (P < 0.001). The diameter of the zones of inhibition increased with time for all materials, fresh and aged. IRM and both the HAP-modified forms produced large zones of inhibition. Amalgam produced no measureable zones of inhibition whether aged or fresh, regardless of period of exposure and was different from the other materials (P < 0.001). The cytotoxicity was assessed using the Millipore filter method. Ten standardized pellets of each material were produced and aged by storage in sterile distilled water for 72 h. Ten filters were included as controls. Amalgam produced a consistent cytotoxic score of 1, and the difference between amalgam and the other materials was statistically significant (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

3T3 Cells↗
PubMed1994

A radiographic study of the effect of various retrograde fillings on periapical healing after replantation.

An effective retrograde sealing procedure places great demands upon both technique and materials. Prevention of micro-leakage, biocompatibility and stability of the material in the apical tissues are very important. To evaluate potential retrograde filling materials, a replantation model has been developed in which extracted permanent molars were replanted in monkeys after apicectomy of each root, preparation of a 2-mm deep retrograde cavity and its sealing with various dental materials. Prior to retro-filling the remaining pulp was exposed to saliva. Apicected molars which were infected and did not receive retrograde fillings served as positive controls. Periapical healing was evaluated radiographically after 8 weeks based on planimetric measurements of the size of the periapical radiolucency. The following dental materials were tested: amalgam, glass ionomer cement, calcium-hydroxide lining cement, AH 26 root canal sealer, various zinc oxide-eugenol cements, Cavit, and gutta-percha with various sealers. The materials which were associated with better apical healing than the infected controls were glass ionomer cement, Cavit, and the zinc oxide-eugenol cements. When plain zinc oxide-eugenol or IRM were combined with a gutta-percha core, healing was best and not statistically different from normal apices. It was concluded that radiographic assessment at 8 weeks of molar teeth retrograde filled prior to replantation could be a valuable method for discrimination of potentially useful materials in vivo.

Analysis of Variance↗
PubMed1994

Cytotoxicity of potential retrograde root-filling materials.

The cytotoxicity of potential retrograde root-filling materials was assessed using the Millipore filter method. A light-cured glass ionomer cement, Vitrebond (VB), and three reinforced zinc oxide-eugenol cements, Kalzinol, IRM and ethoxybenzoic acid (EBA) cement, were compared with amalgam. Twenty standardized pellets of each material, 10 fresh and 10 aged by storage in sterile distilled water for 72 h were produced. Ten filters were included as controls: five filters with a cell monolayer, but without test specimens, and another five without cells but with test specimens. Fresh IRM exhibited the most pronounced cytotoxic effect and the difference was statistically significant compared with all the other materials. There was no statistically significant difference between fresh VB, Kalzinol, EBA cement and amalgam. When aged, Kalzinol was the most cytotoxic and the difference was statistically significant compared with the other materials. Aged IRM was the second most cytotoxic material and this too was statistically different. The cytotoxicity of VB, EBA, and amalgam did not differ significantly from one another.

3T3 Cells↗
PubMed1995

A complex treatment of dens invaginatus.

Dens invaginatus is a developmental malformation of teeth. A case is presented of successful treatment of a peg lateral incisor with a severe dens invaginatus extending to the root apex. Both conventional endodontic therapy and periapical surgery were ineffective in resolving a persistent, long-standing sinus tract. Removal of the tooth in the present case would have created a difficult prosthetic problem. Intentional replantation, with improved access to the apical part of the canal was attempted as a last resort. A 10-month recall radiograph is presented showing successful healing of the periapical lesion. Pre-treatment and post-treatment photographs are presented to show successful esthetic treatment, using bonded composite resin.

Adult↗
PubMed1995

Efficacy of XeCl-308 excimer laser in fusing hydroxyapatite to seal the root apex.

Sealing the root apex during apical surgery is important for a successful outcome. The effect of XeCl-308 nm excimer laser irradiation on the fusion and seal of hydroxyapatite to the root apex was tested in extracted human teeth. Twenty-four roots of intact single-rooted premolars were instrumented to size 30 K-file at the apex leaving a patent apical foramen. The apex of each tooth was covered with a freshly prepared paste of hydroxyapatite powder mixed with saline. The samples were then divided into two groups. In 12 teeth, the apical area was irridiated with XeCl-308 nm excimer laser at a fluence of 0.7 J/cm2 for 5 s with pulse repetition rate of 25 Hz and a spot size of 0.13 cm2 immediately after the hydroxyapatite application. In the other 12 teeth, no laser treatment was performed after the hydroxyapatite application. The roots were mounted on a model for the detection of radicular leakage of hydrogen peroxide. The hydrogen peroxide leakage of each sample was measured and the difference between the test groups compared. The ability of the hydroxyapatite plug to prevent hydrogen peroxide leakage at the apex was also tested by applying compressed air from the triple syringe on the coronal access preparation for 2 min. Apical leakage was found in four teeth in the lased group and in eight teeth in the non-plased group. However, the difference between the groups was not statistically significant. Compressed air applied to the coronal access caused hydrogen peroxide leakage in all the teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Chi-Square Distribution↗
PubMed1995

Cutting ability of an ultrasonic retrograde cavity preparation instrument.

The aim of this study was to investigate the cutting ability of a working ultrasonic instrument designed for surgical endodontic use (Neosonic, Amadent Corp, Cherry Hill, NJ, USA). Three designs of tip, designated CT 1 to CT 3 were calibrated by measuring their displacement amplitudes in air using light microscopy over a range of power settings. Extracted teeth were sectioned longitudinally and polished to produce a smooth dentine surface onto which the tips were applied for 1 minute over the above range of power settings at a load of approximately 20 g. The depth of cut in the dentine surface was measured using a two dimensional surface profilometry technique. Results showed that a raising of the power setting produced an increase in displacement amplitude and cutting ability for all tip designs. This increase was linear, with minimal cutting occurring at lower power settings. In conclusion the ultrasonic tips could be successfully used to remove dentine, and medium to high power settings optimised their efficiency.

Analysis of Variance↗
PubMed1995

Importance of anatomic variables in endodontic treatment outcomes: case report.

Surgical endodontic treatment was performed after a large periradicular lesion failed to resolve following nonsurgical intervention. The subsequent periradicular surgery resulted in healing with scar formation. Assessment of the resected root apex revealed a complex anatomy. The ramifications of these anatomical findings and the periradicular tissue response in healing are discussed relative to prognosis and ultimate treatment outcomes.

Adult↗
PubMed1995

Sealing ability of potential retrograde root filling materials.

The sealing ability of two potential retrograde root filling materials, a light-cured glass ionomer cement (Vitrebond) and a reinforced zinc oxide-eugenol cement (Kalzinol) was compared with that of amalgam using three methods of assessment: bacterial leakage, confocal microscopy and Indian ink leakage. the root canals of 80 extracted human single-rooted teeth were prepared. All the teeth were apicected, retrograde cavities were prepared and then divided into four equal groups of 20 teeth. The teeth were sterilised by autoclaving and the retrograde cavities filled with the test materials. In the control group, retrograde cavities in 10 teeth were left unfilled while cavities in another 10 teeth were sealed with cyanoacrylate cement. The teeth were first subjected to a bacterial leakage test using Enterococcus faecalis as a leakage marker. After which, the adaptation of the retrograde root fillings was assessed using a confocal optical microscope. Finally, the teeth were processed for the Indian ink leakage test. Bacterial leakage occurred in more teeth filled with amalgam compared with both Vitrebond and Kalzinol (P<0.001), between which there were no differences. With confocal microscopy, the size of the marginal gap was largest with amalgam and smallest with Vitrebond; all differences were statistically significant (<0.001). Finally, there was more Indian ink penetration with amalgam compared with both Vitrebond and Kalzinol (P<0.001) but there were no differences between Vitrebond and Kalzinol. Although there were individual differences within samples, overall, the three methods of assessment produced similar results. The sealing ability of Vitrebond and Kalzinol was similar and both materials were better than amalgam.

Carbon↗
PubMed1996

Effect of various sealers with gutta-percha as root-end fillings on healing after replantation.

This study examined histologically the effect of three sealers used with gutta-percha as root-end fillings placed in a replantation model. A total of 14 molar teeth were used in seven monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root-end cavities prepared, and fillings of gutta-percha and sealer placed prior to replantation. After 8 weeks the teeth and surrounding jaw were removed and prepared for histological examination. Six roots filled with gutta-percha plus a fortified zinc oxide-eugenol cement (IRM), 13 with gutta-percha plus zinc oxide-eugenol (EP), and eight with gutta-percha plus Kloropercha, were available for examination. The tissue response to gutta-percha with either zinc oxide material was characterized by little or no inflammation of limited extent. In contrast, more severe inflammation was observed against root ends filled with gutta-percha and Kloropercha. Gutta-percha plus IRM or zinc oxide-eugenol had a much more favourable response than that to amalgam reported previously in a similar experiment.

Animals↗
PubMed1996

Cutting characteristics of a sonic root-end preparation instrument.

The aim of this study was to investigate the cutting ability of retro tips powered by a sonic handpiece (MM 1500, Micro Mega, Prodonta, Geneva, Switzerland). Two levels of the following variables were evaluated in this study: a) power setting with the an inlet ring half or fully open, b) orientation of tip perpendicular or parallel to the long axis of the handpiece, c) length of tip 2 or 3 min, d) loading of 25 or 50 grams, e) tip size 35 or 55. The substrate used was 1 mm thick sections of bovine bone and load was controlled by using a load cell interfaced with a transducer meter. Instrumentation time was fixed at 10 seconds with water irrigation. A 2(5) full factorial analysis was performed with two replications making a total of 64 experimental units. The resultant depth of cut was measured using a stereo microscope at x50 magnification. Analysis of the data indicated that all variables had a significant effect on cutting (ANOVA p < 0.05). The most significant factor was power, followed by tip length tip orientation, width and load. An increase in loading resulted in tip constraint and a reduction of cutting at the lower power setting. In conclusion sonically activated retro tips were found to cut satisfactorily with instrument air inlet ring opening/power having the main effect.

Analysis of Variance↗
PubMed1996

Effect of retrograde cavity preparations on root apexes.

Ultrasonic cavity preparations in endodontic surgery has become a popular procedure with several advantages noted: Smaller cavities, deeper and cleaner preparations, less removal of surrounding bone needed for instrumentation and less removal of root apex dentin. Concern has been raised that lines of infraction have appeared in some instances when the ultrasonic instruments have been used. We wished to examine the result of cavity preparations in root apexes using five different methods: high and slow speed handpieces, sonic instruments, and ultrasonic instruments at two power settings, medium and high levels, respectively. The results showed that all the methods produced some infractions; the high power ultrasonics produced the most infractions while the lowest numbers were associated with the slow speed handpiece and ultrasonic instruments at the medium power setting.

Dental Equipment↗
PubMed1996

Root end filling materials: a review.

When non-surgical attempts prove unsuccessful or are contraindicated, surgical endodontic therapy is needed to save the tooth. The procedure usually consists of exposure of the involved area, root end resection, root end preparation and insertion of a root end filling material. Numerous materials have been suggested as root end filling materials. This article is a review of the literature on the suitability of various root end filling materials based on their leakage assessment, marginal adaptation, cytotoxicity, and usage test in experimental animals and humans.

Animals↗
PubMed1997

Radiological assessment of the effects of potential root-end filling materials on healing after endodontic surgery.

The effects of three root-end filling materials on healing following endodontic surgery were assessed radiologically and correlated with histological findings reported elsewhere. The materials compared were a light-cured glass ionomer cement (Vitrebond), a reinforced zinc oxide-eugenol cement (Kalzinol) and amalgam. The root canals of 27 two-rooted mandibular premolar teeth of six beagle dogs were inoculated with endodontic pathogenic bacteria to induce periradicular lesions. The roots were apicected and root-end cavities filled with the tested filling materials. The teeth and surrounding jaw were removed after 4 weeks (30 roots) or 8 weeks (24 roots). Radiographs were taken of each jaw section and subjected to image analysis. Healing was evaluated based on measurements of the size of the periradicular radiolucent areas. ANOVA disclosed no statistically significant differences in the size of the periradicular areas either between time periods or between materials. These results did not correlate with the tissue responses in the same material as assessed histologically and previously reported. The use of radiographs alone to assess healing after endodontic surgery in the dog mandible is unsatisfactory, and should not be regarded as a substitute for histological examination for the determination of healing.

Analysis of Variance↗