Till Dammaschke

Long-term Survival of Root-canal–treated Teeth: A Retrospective Study Over 10 Years

In this retrospective study the survival rate of 190 root-canal-treated teeth of 144 patients after 10-yr minimum was evaluated. Students during their training in 1987 and 1988 had performed the treatments. Age, gender, jaw, or quantity of root canals had no influence to the success of a root-canal treatment. Teeth with an apical lesion before the endodontic treatment showed a significantly shorter likelihood of survival. The best results could be found in root-canal fillings ending 0 to 1 mm and 1 to 2 mm before the apex. Comparing types of restoration, prosthetic-treated teeth with retention post and crown seem to be favorable. The study showed that root-canal treatment even conducted by students has a survival rate of 85.1% (Kaplan-Meier) after 10 yr and is a long-lasting, conservative therapy.

Reaction of sound and demineralised dentine to Carisolv in vivo and in vitro

OBJECTIVES The aim of the present study was to assess the structural reaction of intact dentine to Carisolv in vivo and in vitro. METHODS For the in vivo study occlusal cavities were prepared in 48 caries-free molars in Wistar rats (age: three months) and Carisolv-solution was placed into the cavities of 24 M for 1, 10 and 20 min. Twenty four contralateral molars served as controls and were treated with an inert liquid containing purified water, carmellose and erythrosin for corresponding periods. For the in vitro study 24 rat molars were resected en bloc and fractured to expose an area of crown dentine area. Molars were demineralised with EDTA for eight weeks to expose the collagenous dentinal matrix. One half of the specimens was then coated with Carisolv-solution for 20 min. The other half served as a control and was coated with an inert solution for 20 min. RESULTS In the in vivo specimens no signs of pulp cell damage were observed in the experimental group. The odontoblastic processes were destroyed in proximity to the floor of the cavity but were intact in the inner portion of dentinal tubules in experimental molars and a mechanical damage was noted in the control molars. In the in vitro specimens no structural discrepancy was detected between the experimental molars and the control molars in collagen fibrils of demineralised dentine. CONCLUSIONS Carisolv causes destruction of cellular components of odontoblastic processes but does not attack healthy collagen fibrils.

Histocytological evaluation of the reaction of rat pulp tissue to Carisolv

OBJECTIVES Carisolv is a viscous substance for the chemo-mechanical removal of caries. The aim of this study was to examine the tissue reactions of pulp and dentin tissue to Carisolv in vivo. METHODS In 48 caries-free molars (24 Wistar rats, age: 3 months) an occlusal cavity was prepared. The roofs of the pulp chambers were perforated with a sharp probe and Carisolv solution was placed onto the exposed pulp of 24 molars for 1, 10 and 20 min. Twenty-four contralateral molars served as controls and were coated with an inert liquid containing isotonic saline solution, carmellose and erythrosin. RESULTS After a contact period of 10 and 20 min in the experimental group, pulpal destruction of intercellular substance and cells including odontoblasts was observed up to a depth of 150 microm, in addition to the mechanical damage by perforation (e.g. dentin particles). The pulpal and predentin fibrils as well as the dentin fibrils appeared to be intact and did not differ from the controls. After a contact time of 1 min a weaker damage of pulp cells and odontoblasts, as well as intact fibrils in pulp, predentin and dentin could be observed. CONCLUSIONS Radicals of Carisolv (OH- and OCI-) cause alkaline hydrolysis of cellular components but do not decompose collagenous tissue components.

Influence of coronal restorations on the fracture resistance of root canal‐treated premolar and molar teeth: A retrospective study

To evaluate the influence of coronal restorations on the fracture resistance of endodontically treated teeth, 676 root canal-filled and restored posterior teeth were evaluated after a mean period of 9.7 (± 2.8; minimum: 5) years. A total of 86.2% of the endodontically treated and restored teeth survived the mean observation period of 9.7 years without fracture. The overall survival period was 13.6 (± 0.2) years. All teeth with gold partial crowns survived without fractures (n = 24). Teeth with crowns and adhesively sealed access cavities showed a mean survival period of 15.3 (± 0.4) years, with crown and bridge restorations 14.0 (± 0.3), with individual metal posts 13.9 (± 0.2), with composite fillings 13.4 (± 0.5), with prefabricated metal posts 12.7 (± 0.6), with amalgam fillings 11.8 (± 0.6) and with glass ionomer cements (GIC) 6.6 (± 0.5) years. Teeth with one or two surfaces restored by amalgam, composite or GIC showed a significantly lower fracture rate than teeth with three and more restored surfaces (P < 0.05). The mean fracture rate of teeth restored with GIC was significantly higher when compared with all other groups (P < 0.001). In general, endodontically treated teeth restored with prosthetic restorations demonstrated a significantly lower mean fracture rate than teeth restored with fillings. Cavities with up to three surfaces may well be successfully restored adhesively with composite filling material.

Effect of root canal dressings on the regeneration of inflamed periapical tissue

The aim of this study was to evaluate the effects of chlorhexidine and calcium hydroxide on apical periodontitis in rats. Experimentally induced apical periodontitis was established on the mesial roots of maxillary molars of Wistar rats by leaving the root canals exposed to the oral cavity for 14 d. In the positive control group (n=10 teeth), the root canals were not further treated, but the coronal access openings were filled with composite. In the negative control group (n=10 teeth), partial pulpotomies were performed aseptically and the coronal access openings were sealed immediately. In a third control group (n=10 teeth) the canals were instrumented, left empty, and the coronal access openings were sealed. In the experimental groups, the root canals were instrumented and filled with either 2% chlorhexidine gel or calcium hydroxide paste (n=10 teeth per group). After 7 d all rats were killed and the histological sections were stained for microscopic analysis of periapical regeneration. The data of the subjective evaluation were analyzed with the Kruskal-Wallis test. Lesion sizes were measured and statistically analyzed using the ANOVA and post-hoc Scheffé test. The two treatment groups showed significantly lower average inflammatory scores and smaller lesion sizes than the positive and third control group (p<0.05). No statistically significant differences were obtained between the two treatment groups (p>0.05). Chlorhexidine used as an intracanal medicament showed good periapical regeneration, suggesting that this may be an alternative to calcium hydroxide root canal dressing.

Effectiveness of Carisolv compared with sodium hypochlorite and calcium hydroxide

The aim of this study was to compare the effectiveness of Carisolv with that of two other alkaline substances: NaOCl and Ca(OH)2. Sixty extracted teeth were randomly divided into three groups and split down the center of a carious lesion. In group I, one half of the cavity was excavated with NaOCl (0.5%, pH 11.7), the corresponding half with Ca(OH)2 (pH 12.4); in group II with NaOCl and Carisolv; and in group III with Ca(OH)2 and Carisolv (n=20 in each case). Carisolv hand instruments were used. Histological specimens were subsequently produced from all cavities and analyzed with a light-microscope following Mallory-Azan staining. The thickness of the remaining caries was measured (<1 mm or >1 mm) and the locations were recorded. The data were statistically evaluated using the chi-square test. In group I, 50.5% of the specimens treated with NaOCl and 48.7% treated with Ca(OH)2 were evaluated to be caries-free. The results in group II were NaOCl 61.5% and Carisolv 75.4% caries-free, and in group III Ca(OH)2 61.2% and Carisolv 73.9%. No statistically significant differences were found between NaOCl and Ca(OH)2 excavation (group I: p=0.89). Compared to NaOCl and Ca(OH)2, Carisolv produced significantly better results for chemo-mechanical caries removal (groups II+III: p<0.05). In the NaOCl and Ca(OH)2 treated specimens, carious layers with a thickness >1 mm were found significantly more often than in the Carisolv-treated specimens (groups II+III: p<0.05), whereas there were no differences between NaOCl and Ca(OH)2 excavation (p=0.06). There were no statistically significant differences in the location of the remaining caries in any of the groups (p>0.05).

Cytotoxic effects of four different root canal sealers on human osteoblasts

The aim of this study was to evaluate the effect of an epoxy resin-based (AH-Plus), a zinc oxide eugenol containing (Pulp-Canal-Sealer) and two calcium silicate containing (MTA-Fillapex and BioRoot-RCS) sealers on primary human osteoblasts (hOB) in freshly mixed and set state. All sealers were mixed strictly according to the manufacturers´ instructions and identically samples were produced. In a pretest cytotoxic sealer concentrations were determined. Thus, for the main cell culture study, dilutions of sealer extract 1:1, 1:2, and 1:10 were used. To simulate a clinical scenario, extracts from freshly mixed sealer were added to the cells on day one. Extracts form set sealers were used for subsequent culturing for 24h, 7d, 14d, and 21d. Cell viability was analyzed by living-cell-count, MTT-assay, and living/dead-staining, cytotoxicity by LDH-assay, and changes by Richardson-staining. All data were statistically evaluated by one way ANOVA and a posthoc analysis with Bonferroni-Holm testing (p<0.05). AH-Plus was cytotoxic in a freshly mixed state, but not when the sealer was set. MTA-Fillapex and Pulp-Canal-Sealer were cytotoxic in a fresh as well as in a set state. BioRoot-RCS showed the lowest toxicity in both states; where as a regeneration of the cells could be observed over time (p<0.05). Contact of freshly mixed AH-Plus to osteoblasts should be avoided. Pulp Canal Sealer and MTA-Fillapex showed no biocompatibility in contact with osteoblasts at all. BioRoot-RCS had a positive influence on the cell metabolism (bioactivity) and is biocompatible.

The effect of different root canal medicaments on the elimination of Enterococcus faecalis ex vivo

Objective: The aim of this study was to evaluate the antimicrobial effect of chlorhexidine gel (CHX-G) 2%, chlorhexidine powder (CHX-P) 1%, povidone-iodine (PVP-I), polyhexanide and camphorated-and-mentholated chlorophenol (ChKM) ex vivo. Materials and Methods: For every medicament group 10 root segments (15 mm long) of extracted human teeth were prepared to ISO-size 45 and sterilized (n = 50). The root segments were then inoculated with Enterococcus faecalis and aerobically incubated at 37°C. After 1 week, ten root canals were filled with one of the medicaments, respectively and aerobically incubated at 37°C for another week. Ten teeth served as positive controls and were filled with sterile saline solution. After 7 days, the medicaments were inactivated and all root canals were instrumented to ISO-size 50. The obtained dentin samples were dispersed in Ringer solution followed by the preparation of serial dilutions. 10 ΅l per sample were applied to an agar plate and incubated at 37°C for 48 h. The colony forming units were counted and the reduction factors (RFs) were calculated and statistically analyzed. Results: Compared with the positive controls all medicaments exhibited an antibacterial effect against E. faecalis. The RFs for CHX-G, CHX-P and ChKM were significantly higher compared to PVP-I and polyhexanide (P < 0.05). In contrast to PVP-I and polyhexanide, CHX-G, CHX-P and ChKM were able to eliminate E. faecalis from all dentin samples. Conclusions: Within the limitations of this ex vivo investigation, 2% CHX-G and CHX-P were as effective as ChKM against E. faecalis. Thus, when choosing a root canal medicament the better biocompatibility of CHX compared with ChKM should be taken in consideration.

Solubility and pH Value of 3 Different Root Canal Sealers: A Long-term Investigation

Introduction: The aim of this study was to compare the solubility and the change in pH of a tricalcium silicate–containing sealer (BioRoot RCS [BR]), a mineral trioxide aggregate–containing sealer (MTA Fillapex [MTA]), and an epoxy resin–based sealer (AH Plus [AH]) during a longer period of time. Methods: The solubility test was carried out in accordance with ISO6876:2012. Three hundred eighty sealer samples (n = 10 per group) were stored for 6 months in double distilled water (AD) or phosphate‐buffered saline (PBS). The solubility was determined on the basis of the mass difference in percent. The pH measurement was carried out on the basis of the experimental setup of the solubility test with the aid of an electrode pH meter. The results were evaluated for significance by using analysis of variance, Student‐Newman‐Keuls, and t test (P < .05). Results: The highest solubility was found for MTA in AD (4.65% ± 1.17%), followed by BR in AD (3.88% ± 0.42%) (P < .05). Also in PBS, MTA (3.24% ± 0.7%) showed a higher solubility than BR (1.78% ± 0.5%) (P < .05). AH was virtually insoluble during the entire period (0.5% ± 0.5%) (P < .05). The pH decreased continuously over time for all samples. After 6 months, BR showed the highest pH in AD (pH 10.3), followed by MTA in AD (pH 8.8), BR in PBS (pH 7.5), AH in PBS (pH 7.3), MTA in PBS (pH 7.2), and AH in AD (pH 6.3). Conclusions: The solubility of MTA was significantly increased compared with BR and AH. Storage in PBS significantly reduced solubility of MTA and BR. BR showed a higher pH in both AD and PBS than MTA in AD and PBS. AH did not cause any significant pH change.