Root dentin morphology after different modes of citric acid and tetracycline hydrochloride conditioning

Root surface biomodification in periodontal therapy: Biological rationale and clinical applications

Regenerative periodontal therapy aims to form new cementum, periodontal ligament, and alveolar bone, all sealed by gingival tissue. The root surface acts as the wound margin during this regeneration process. Root surface biomodification (root conditioning/root decontamination), therefore, seems instrumental in promoting surface decontamination and enhancing tissue attachment by removing the smear layer, exposing collagen fibrils, and facilitating blood clot formation and stabilization. This review attempted to provide an all-encompassing, evidence-based assessment of the role of root surface biomodification in regenerative periodontal therapy, particularly in intrabony defects, furcation defects, and root coverage procedures. The reviewed evidence suggested that root conditioning agents, whether used independently or in conjunction with bone graft materials, biological agents, membranes, or connective tissue grafts, do not offer any clinical advantage regarding clinical attachment gain. Thus, integrating chemical methods with the mechanical root instrumentation process does not necessarily contribute to superior clinical outcomes.

Clinical evaluation of lateral pedicle flap stabilized with cyanoacrylate tissue adhesive: A randomized controlled clinical trial

Context:

Gingival recession is the most common mucogingival defect and is susceptible to tooth hypersensitivity, root caries, and esthetic problems if left untreated. A lateral pedicle flap is used to cover denuded roots that have adequate donor tissue laterally and adequate vestibular depth. A carefully planned surgery needs proper immobilization of the flap at the recipient site and this can be achieved by proper wound closure technique with appropriate material such as sutures or tissue adhesives.

Aim:

The aim of the present study is to evaluate the clinical outcomes of lateral pedicle flap stabilized with cyanoacrylate tissue adhesive and resorbable sutures.

Materials and Methods:

Twenty-two patients with Miller's class I and class II gingival recession were randomly divided into two groups: lateral pedicle flap stabilized with cyanoacrylate tissue adhesive (test) and lateral pedicle flap stabilized with resorbable sutures (control). Plaque index, gingival index, probing pocket depth, clinical attachment level, recession depth and width, height and thickness of keratinized gingiva were evaluated at baseline and 1^st and 3^rd month postoperatively. The percentage of root coverage was evaluated at the end of 3^rd month postoperatively.

Statistical Analysis Used:

Intergroup comparisons for the clinical attachment level, recession depth, recession width, thickness of keratinized gingiva, and height of keratinized gingiva were made by Mann–Whitney test by analyzing the difference of two time periods. Intragroup comparisons were made by the Kruskal–Wallis test. Mann–Whitney test was used to compare the difference between various time periods within the group for all the selected variables.

Results:

The mean plaque index and gingival index at the 1^st and 3^rd month were found to be statistically significant and did not present any significant influence over other clinical parameters evaluated. A partial root coverage was observed in both the groups (71.97% for the test group and 61.36% for the control group).

Conclusions:

Cyanoacrylate tissue adhesive is clinically effective in the stabilization of the lateral pedicle flap and can be used as an alternative to resorbable sutures.

Different Regenerative Responses of Two Platelet Concentrates in the Treatment of Human Periodontal Infrabony Defects: A Clinico-Radiographic Study

Background:

Platelet concentrates usage in the treatment of intrabony defects has been improved due to advancement of research. Many generation of platelet concentrates were used, but research regarding advanced platelet-rich fibrin (A-PRF) regarding periodontal treatment is scanty.

Aim:

The purpose of the study was to evaluate and compare PRF and A-PRF in the treatment of human periodontal infrabony defects (IBDs) both clinically and radiographically.

Materials and Methods:

Twenty-eight patients having IBDs were divided into Group A (PRF) and Group B (A-PRF). Clinical parameters such as plaque index, gingival index, probing pocket depth (PPD), and clinical attachment level (CAL) were recorded at baseline and 3 and 6 months and radiographic examination at baseline and 6 months were also recorded to evaluate defect fill, resolution, and change in the alveolar crest height. Then, all the data were tabulated in a Microsoft Excel sheet and subjected to statistical analysis. Mean and standard deviations of the clinical and radiographic parameters were calculated, and unpaired t-test was performed to assess intergroup comparison at different time intervals.

Results:

Intragroup comparison showed statistically significant improvement in PPD and CAL at 3 and 6 months while statistically significant improvement was observed in mean defect fill and resolution in Group B.

Conclusion:

Individually, both the materials have shown promising results. However, statistically, PRF group (Group A) showed better treatment outcome in terms of bone fill and A-PRF group (Group B) in terms of soft tissue healing.

Bone demineralization improves onlay graft consolidation: A histological study in rat calvaria

BACKGROUND

Previous data suggest that bone demineralization may promote bone graft consolidation as well as proliferation and differentiation of pre-osteoblasts, but the biological mechanisms involved in this process need to be clarified. This study investigated the effects of bone demineralization with citric acid (CA) and tetracycline (TCN) on the repair of onlay bone grafts.

METHODS

Onlay bone grafts were performed on the calvaria of 126 Wistar rats. The contacting surfaces between bone graft and receptor bone bed were demineralized for 15, 30, and 60 seconds with TCN (50 mg/mL), or 10% CA, (pH 1), constituting the following test groups (n = 18): TCN15, TCN30, TCN60, CA15, CA30, and CA60. Control grafts (C) were performed without demineralization (n = 18). After 7, 30, and 60 days, biopsies were obtained for quantitative and qualitative histological analysis (a = 6).

RESULTS

Demineralization accelerated the bone repair early from 7 days of healing. Higher percentage area of newly formed bone was observed in CA15 and TCN60 groups when compared to C in all evaluation periods (P = 0.02). At 30 days, C specimens had lower percentage of consolidated surfaces than TCN60, TCN30 and CA15 (P = 0.0015). At 60 days, CA15, CA60, and TCN60 presented bone surfaces almost completely filled by newly formed bone, against about 75% in C specimens (P = 0.0015).

CONCLUSIONS

Both CA and TCN were effective in accelerating osteogenesis at the interface between bone grafts and receptor bone beds, especially when applied for 15 seconds and 60 seconds, respectively.

Oral Soft Tissue Grafting

The presence of healthy soft tissue at the tooth and implant interface correlates to long-term success and stability in function and esthetics. Grafting procedures utilizing various techniques can be performed during any stage of the implant or restorative therapy. Materials of autogenous, allogeneic, and xenogeneic sources are available for oral soft tissue grafting. This article describes the classifications of soft tissue defects, treatment modalities, and materials used to enhance soft tissue quality and quantity and to achieve optimal esthetics and function around teeth and implants.

The concentration of citric acid as dental root conditioner influences the behavior of fibroblasts from human periodontal ligament

OBJECTIVE

This study investigated the behavior of fibroblasts from human periodontal ligament (hPLF) cultured on dental roots subjected to different protocols of citric acid conditioning.

MATERIALS AND METHODS

32 human teeth extracted due to advanced periodontal disease provided 63 radicular fragments, which were randomly divided in groups according to the treatment given to the surface: rinsing with saline solution for 90 s (C), 10 % citric acid (CA10), or 50 % citric acid (CA50). The treatments were applied during 90 s, 120 s and 180 s (n = 9). hPLF were cultured for 24, 48 and 72 h (n = 3) on the treated samples and analyzed by scanning electron microscopy (SEM) for surface area covered by cells and dentinal tubules widening.

RESULTS

Excepting group C, all the other groups showed almost complete coverage of root surface by hPLF with time. At 24 h of cell culture, the largest area of coverage was seen in the samples treated with CA10-90 (98 ± 0.89 %) at 24 h of cell culture and this difference was significant (p < 0.05) in comparison to CA10-180 (84.04 ± 5.01 %), CA50-90 (63.28 ± 12.46 %), CA50-180 (56.59 ± 8.76 %) and C (0.06 ± 0.11 %). In all the other comparisons, there was no statistically significant differences between CA10 and CA50 (p > 0.05). Cells grown on surfaces treated with CA10 were more spread and flatten than in the CA50 specimens.

CONCLUSIONS

Periodontally compromised roots surfaces conditioned with 10 % citric acid for 90 s resulted in better substrate for hPLF proliferation, in initial periods of culture than 50 % citric acid. The enlargement of the dentinal tubules did not seem to be influenced by the acid concentration.

Effects of Tetracycline, EDTA and Citric Acid Application on Nonfluorosed and Fluorosed Dentin: An In Vitro Study

Fluorosis is one of the factors that may bring about mineralization changes in teeth. Routine treatment of root biomodification is commonly followed during Periodontal therapy.

BACKGROUND

The Purpose of the present study was to compare and evaluate the morphological changes in fluorosed and nonfluorosed root dentin subsequent to the application of Tetracycline, EDTA and Citric acid. Both fluorosed and nonfluorosed teeth comprising of periodontally healthy and diseased were included in this study.

METHOD

Each of them was grouped into Tetracycline Hydrochloride, EDTA and Citric acid treatment groupes. Using scanning electron microscope (SEM), the photomicrographs of dentin specimens were obtained.

RESULTS

Showed that there was no significant difference in exposure of number of tubules in different groups, while significant increase in the tubular width and tubular surface area was seen in fluorosed healthy, followed by fluorosed diseased groups, nonfluorosed healthy and nonfluorosed diseased groups after root biomodification procedure using various root conditioning agents. The root biomodification procedure brings in definite difference between fluorosed and nonfluorosed dentin specimens.

An in vitro scanning electron microscope study to evaluate the efficacy of various root conditioning agents

AIM

The purpose of present study was to investigate the scanning electron microscopic alterations produced on scaled and root planed dentin surfaces after application of different etching modalities namely citric acid, tetracycline hydrochloride and ethylenediaminetetraacetic acid (EDTA).

MATERIALS AND METHODS

Eighty specimens of teeth were collected and categorized into four groups. In group 1, control group specimens were treated with normal saline for 3 min, group 2 specimens were treated with citric acid, group 3 specimens were treated with tetracycline hydrochloride for 3 min and group 4 specimens were treated with 15% EDTA.

RESULTS

Opening of dentinal tubules was seen in all specimens except for control group that was treated with normal saline. The total number of tubules seen was highest in citric acid group as compared to tetracycline hydrochloride and EDTA Group. The total number of patent tubule opening was highest in citric acid as compared to EDTA and tetracycline. The diameter of patent dentinal tubules in citric acid group was more than EDTA and tetracycline.

CONCLUSION

The study showed that all the three agents were effective in removing the smear layer however number of patent and wider diameter dentinal tubules was seen in vitro best in citric acid than EDTA and then in tetracycline hydrochloride. Hence, citric acid group is more efficient than EDTA and tetracycline HCl group in removing the smear layer and in opening of number of patent dentinal tubules.

Effect of various concentrations of tetracycline hydrochloride demineralization on root dentin surface: A scanning electron microscopic study

Introduction:

Within the last 20 years root demineralization has attracted attention as a periodontal regenerative technique. Topical tetracycline application has been widely reported for use as a conditioner, to decontaminate the root surface and to promote periodontal regeneration. The purpose of this scanning electron microscopic (SEM) study is to evaluate the surface characteristics of demineralized diseased and non-diseased dentine root surfaces using different concentrations of tetracycline hydrochloride (TTC-HCl).

Material and Methods:

This SEM study was carried out in 20 dentin samples obtained from non-diseased human premolars and 20 dentin samples obtained from diseased human premolars. Pure TTC-HCl was applied to the dentin surface at 50 mg/ml, 100 mg/ml and 150 mg/ml concentrations for 3 min in experimental groups while distilled (0 mg/ml) water was applied to the control groups.

Statistical Analysis:

Mean and standard deviation were estimated from the sample for each study group. Mean values were compared by either one-way ANOVA with Tukey-Honestly significant difference procedure or Kruskal - Wallis one way ANOVA with Mann-Whitney u-test. Further Student′s independent t-test/Mann-Whitney u-test was used appropriately to compare the mean values between two independent groups.

Results:

In the present study using 100 mg/ml tetracycline seems to be more effective on both diseased and non-diseased dentin surfaces.

Conclusions:

The results of this study confirm that pure TTC-HCl conditioning produced comparable surface characteristics on dentin of both diseased and non-diseased roots with 100 mg/ml concentration for 3 min.

Debris and smear layer removal efficacy and changes in morphology of dentinal tubules after using citric acid, tetracycline-hydrochloride and mixture of tetracycline and acid and detergent

Background:

In periodontal diseases, contamination of roots with bacteria and their active biologic agents and smear layer formation following periodontal treatments, prevents reattachment of periodontal cells. As a matter of fact biomodification of root surface and removal of smear layer and debris is critical for regeneration of periodontal structures. The aim of this study was to compare the efficacy of smear layer removal by citric acid, tetracycline-hydrochloride (TTC-HCL) and mixture of tetracycline and acid and detergent (MTAD).

Materials and Methods:

In this in vitro and experimental study, 12 impacted third molars were sectioned from cervical enamel junction (CEJ) to mid-root area into four dentinal specimens (n = 48). Three groups were conditioned by citric acid 3%, TTC-HCL 50 mg/mL and MTAD by means of cotton pellets, which were changed every 30 s for 3 min. The control group was conditioned by distilled water. Images from scanning electron microscope (SEM) were examined by two different analyzers. Data was analyzed by Kroskal Wallis and Mann–Whitney statistical analysis.

Results:

The mean of dentinal tubules diameter was the most in MTAD group and the least in TTC-HCL and this difference was statistically significant (P = 0.05).

Conclusion:

According to the present study, TTC-HCL could remove debris and smear layer but citric acid and MTAD had better debris and smear layer removal efficacy and demineralization effect in comparison with TTC-HCL.

Effects of citric acid and EDTA on periodontally involved root surfaces: a SEM study

AIM

Root debridement by scaling and root planing may not completely remove contaminated cementum particularly in more apical areas. The smear layer formed during root planing inhibits cell migration and attachment leading to impaired marginal periodontal healing. The present study was done to compare the morphological effects of root surface demineralization using citric acid and EDTA as root-conditioning agents.

MATERIALS AND METHODS

Thirty fragments of human dental roots previously exposed to periodontal disease were scaled and randomly divided into the following groups of treatment: Group I: Hand instrumentation and conditioning with normal saline for 5 minutes as control; group II: Hand instrumentation and conditioning with citric acid (pH 1) for 5 minutes and group III: Hand instrumentation and conditioning with EDTA (pH-7.4) for 5 minutes. Scanning electron microscopy was used to check for the presence of residual smear layer and for measuring the number and area of exposed dentin tubules.

RESULTS

The mean efficacy of smear layer removal was compared between groups I and II, groups I and III and groups II and III, it was found to be statistically significant at 5%. When the mean diameter of the dentinal tubules and mean total surface area occupied by the dentinal tubule orifices was compared between groups II and III it was found to be statistically significant at 1% level of significance.

CONCLUSION

Citric acid causes greater degree of morphological alterations than EDTA and is considered to be a better root-conditioning agent. However, the use of EDTA cannot be ruled out.

CLINICAL SIGNIFICANCE

This study supports the hypothesis that demineralizing agents can be used as an adjunct to the periodontal treatment aiming at restoring the biocompatibility of roots and helps in choosing an appropriate agent for root conditioning.

Comparison of fibrin clot adhesion to dentine conditioned with citric acid, tetracycline, and ethylene diamine tetra acetic acid: An in vitro scanning electron microscopic study

AIM

The purpose of this study was to evaluate and compare the root surface changes subsequent to the application of citric acid, tetracycline, Ethylenediaminetetraacetic acid (EDTA), and the combination of citric acid and tetracycline, and its influence on the adhesion of a fibrin clot with and without mild disruptive forces.

MATERIALS AND METHODS

A total of 100 periodontally diseased root specimens were grouped into Saline (control Group I), 24% EDTA gel (Group-II), Citric acid (Group-III), Tetracycline (Group IV), and Citric acid + tetracycline (Group V) treatment groups containing 20 in each. After root conditioning, fresh human blood was applied to each root specimen and was allowed to clot. Ten specimens in each group were rinsed in phosphate-buffered saline and designated as 'Non-agitated'. The remaining ten specimens from each group were rinsed in phosphate-buffered saline on a rotary shaker and designated as 'Agitated'. The roots were processed for scanning electron microscopy (SEM) to assess and compare the clot adhesion on them. The scores were compared through standard statistical packages.

RESULTS

The highest mean blood clot adhesion score was observed in roots treated with a combination of citric acid and tetracycline, whereas, the least score was observed in roots treated with saline.

CONCLUSION

The root specimens treated with the combination of citric acid and tetracycline as well as citric acid alone, best supported the fibrin clot. Tetracycline alone appeared to be less effective in supporting the clot. EDTA gel of 24% was least effective to promote the adhesion of a fibrin clot.

Comparison among four commonly used demineralizing agents for root conditioning: a scanning electron microscopy

Dental roots that have been exposed to the oral cavity and periodontal pocket environment present superficial changes, which can prevent connective tissue reattachment. Demineralizing agents have been used as an adjunct to the periodontal treatment aiming at restoring the biocompatibility of roots.

OBJECTIVE

This study compared four commonly used demineralizing agents for their capacity of removing smear layer and opening dentin tubules.

METHODS

Fifty fragments of human dental roots previously exposed to periodontal disease were scaled and randomly divided into the following groups of treatment: 1) CA: demineralization with citric acid for 3 min; 2) TC-HCl: demineralization with tetracycline-HCl for 3 min; 3) EDTA: demineralization with EDTA for 3 min; 4) PA: demineralization with 37% phosphoric acid for 3 min; 5) CONTROL: rubbing of saline solution for 3 min. Scanning electron microscopy was used to check for the presence of residual smear layer and for measuring the number and area of exposed dentin tubules.

RESULTS

Smear layer was present in 100% of the specimens from the groups PA and control; in 80% from EDTA group; in 33.3% from TC-HCl group and 0% from CA group. The mean numbers of exposed dentin tubules in a standardized area were: TC-HCl=43.8±25.2; CA=39.3±37; PA=12.1±16.3; EDTA=4.4±7.5 and CONTROL=2.3±5.7. The comparison showed significant differences between the following pairs of groups: TC-HCl and CONTROL; TC-HCl and EDTA; CA and CONTROL; and CA and EDTA. The mean percentages of area occupied by exposed dentin tubules were: CA=0.12±0.17%; TC-HCl=0.08±0.06%; PA=0.03±0.05%; EDTA=0.01±0.01% and CONTROL=0±0%. The CA group differed significantly from the others except for the TC-HCl group.

CONCLUSION

There was a decreasing ability for smear layer removal and dentin tubule widening as follows: AC>TC-HCl>PA>EDTA. This information can be of value as an extra parameter for choosing one of them for root conditioning.

Comparitive effects of tetracyclines and citric acid on dentin root surface of periodontally involved human teeth: A scanning electron microscope study

Periodontal diseases produce physical and chemical alterations in the root cementum. Various topical applications as root conditioning agents have been recommended as an adjunct to mechanical root surface debridement to remove smear layer, endotoxins and to expose collagen fibers on dentin surface. The objectives were to compare dentin surface changes following applications of tetracyclines and citric acid to the instrumented root surface of periodontally involved human teeth under scanning electron microscope.The study group comprised of 80 dentin samples, which were prepared from periodontally-compromised teeth, planned for extraction. Diseased surfaces were root planed. The teeth were sectioned and solutions of tetracycline HCl, minocycline, doxycycline and citric acid were applied to the surfaces with cotton pellets for 5minutes.The root surface samples were then examined by scanning electron microscope.Removal of smear layer in all the four groups was near total except a few areas. All four groups showed slight difference in mean number of total dentinal tubules. Minocycline and doxycycline showed no significant difference. The proportion of patent dentinal tubules was (74%) in tetracycline HCl group compared to minocycline (48.3%), doxycycline 42%), citric acid (52%), showing the differences statistically significant. Tetracycline group showed higher number of patent tubules when compared to minocycline, doxycycline and the difference was statistically significant.Results of this study suggest that tetracycline is the best current tetracycline form for root surface conditioning as measured by its ability to affect both dentin smear layer removal and tubule exposure.

Is coronally positioned flap procedure adjunct with enamel matrix derivative or root conditioning a relevant predictor for achieving root coverage? A systemic review

BACKGROUND AND OBJECTIVE

This study is a systemic review of coronally positioned flap, coronally positioned flap+chemical root surface conditioning, or coronally positioned flap+enamel matrix derivative (EMD) for the treatment of Miller class I and II gingival recession.

MATERIAL AND METHODS

All studies available through the Medline database by the end of October 2005 were used. Each study provided mean clinical attachment level, keratinized tissue, probing pocket depth, gingival recession depth and root coverage percentage before and after treatment with coronally positioned flap alone, coronally positioned flap+chemical root surface conditioning, or coronally positioned flap+EMD. Effectiveness was evaluated by comparing the weighted mean average in gingival recession depth, probing pocket depth, clinical attachment level, keratinized tissue and root coverage percentage achieved with the three treatments.

RESULTS

Seven studies for the coronally positioned flap+EMD group, four studies for the coronally positioned flap+chemical root surface conditioning group, and seven studies for the coronally positioned flap group were retrieved for this weighted mean analysis. The results of clinical attachment level, gingival recession depth, and root coverage percentage in the coronally positioned flap+EMD group were statistically significantly better than the changes in the coronally positioned flap and coronally positioned flap+chemical root surface conditioning group at 6 and 12 mo (p<0.001). There was no significant difference at the 6-mo comparison among clinical attachment level, keratinized tissue, probing pocket depth, and gingival recession depth, except in the root coverage percentage for coronally positioned flap and coronally positioned flap+chemical root surface conditioning groups.

CONCLUSION

The results suggest that root coverage by the coronally positioned flap and coronally positioned flap+chemical root surface conditioning procedures were unpredictable but became more predictable when the coronally positioned flap procedure was improved by the modification of adding EMD.

A Morphologicalin VitroStudy of the Effects of Nd:YAG Laser on Irradiated Cervical Dentin

OBJECTIVE

The purpose of this in vitro study was to verify the efficacy of Nd:YAG pulsed laser at 1064 nm in sealing dentinal tubules in vitro, with its resulting morphological changes using clinical parameters applicable to the treatment of dentin hypersensitivity.

BACKGROUND DATA

Although many papers have been written on the subject, no rapid, efficient, and long-lasting treatment for this problem has been developed.

MATERIALS AND METHODS

Twenty healthy extracted human teeth were kept in saline solution. Cervical cement was removed with a no. 57FG bur to expose approximately 4 mm(2) of dentin. Two groups were in the buccal aspect (A and B-irradiated) and one group in the lingual aspect (C-control not irradiated) of the same tooth. Samples with a remaining dentinal thickness between 1 and 1.5 mm were selected. Irradiation parameters were 30 mJ, 0.3W(Group A) and 40 mJ, 0.4 W(Group B); 7 Hz was used in both groups in two 43-sec applications each, with a 10-sec interval. In 10 samples, the dentinal surface underwent SEM examination for study. The other 10 remaining irradiated samples were centrally cleaved to study laser penetration depth in dentin (SEM).

RESULTS

Obliteration of dentinal tubule openings and solidification of the dentin surface were observed in all irradiated samples. Laser penetration depth in dentin (SEM) varied from 1 to 7 microm, depending on irradiation parameters used in each group.

CONCLUSION

We concluded that the use of the Nd:YAG laser was a very effective measure for obliterating dentinal tubule openings.

Removal of Organic Debris from Bovine Dentin Shavings

A common problem with root canal failures is chronic inflammation at the apex caused by overfilling of root canal materials. Dentin filings have been suggested as an apical plug to create a biocompatible barrier between the filling material and the periapical tissue. Unfortunately residual organic material, such as pulp remnants or bacteria, still may be part of the filings. Dentin filings removed from the tooth, cleaned, and then used to form a barrier might serve as an effective barrier. The purpose of this study was to evaluate methods of cleaning dentin of organic debris. NaOCl, sodium dodecyl sulfate, and 1% Triton X-100 were used to treat dentin shavings and were evaluated by a micro bicinchoninic acid protein analysis assay. Two series of experiments were performed. One compared the effect of temperature while using phosphate-buffered saline as a control and the second compared exposure times. The percentage of protein extracted from dentin samples increased with temperature. Sodium hypochlorite at room temperature extracted 24.6%, NaOCl at 37 degrees C extracted 26.9%, and NaOCl at 70 degrees C extracted 33.9%. Only NaOCl at 37 degrees C and 70 degrees C showed statistically significant differences from phosphate-buffered saline at room temperature with p-values of 0.028 and 0.019, respectively. The exposure time series showed a difference between a phosphate-buffered saline solution and 6.25% NaOCl. NaOCl removed approximately 90% of protein compared with 60% for the phosphate-buffered saline. A 10-min exposure to 70 degrees C 6.25% NaOCl may be an efficient means of removing organic material from dentin shavings.

Tetracycline HCl solution as a root canal irrigant

The effect of tetracycline hydrochloride as an endodontic irrigant on smear layer removal was examined by scanning electron microscopy and compared with bidistilled water, 2.5% sodium hypochlorite (NaOCl), and 50% citric acid in 20 extracted teeth. Five teeth, as a control, were irrigated with bidistilled water only in group 1. All the other groups were irrigated with NaOCI during instrumentation. The final rinses were NaOCl in group 2, citric acid in group 3, and 1% tetracycline hydrochloride in group 4. Scanning electron microscopic results and statistical analysis revealed that bidistilled water and NaOCl were ineffective in removing the smear layer, whereas citric acid and tetracycline hydrochloride were significantly more effective (p < 0.001). No statistically significant difference was detected between tetracycline hydrochloride and citric acid (p > 0.05). However tetracycline hydrochloride demineralized less peritubular dentin.

A comparative profilometric in vitro study of the susceptibility of polished and natural human enamel and dentine surfaces to erosive demineralization

This study sought to compare the depths of erosive lesions in samples from different tooth sides as well as from enamel, dentine and root surfaces, and to examine the effect of preparation and polishing of specimens on erosive demineralization. From 30 impacted human third molars, two enamel samples from the mesial, distal, buccal and oral aspects, and similar samples from the radicular dentine, were prepared. One of each pair of samples was polished whereas the other was left untreated. Four samples were also prepared from the coronal dentine. For erosive demineralization, all samples were immersed in 0.05 M citric acid for 3 h and the erosion depth was calculated profilometrically. In general, natural surfaces showed significantly smaller erosion depths than polished surfaces (p< or =0.001) and enamel samples showed greater depths than coronal dentine (not significant) and root dentine (p< or =0.001). The erosion depths of the four tooth sides correlated significantly for polished enamel and coronal dentine samples but not for natural enamel specimens. There was no correlation between erosion depths for enamel and coronal dentine, and only a weak correlation between enamel and root dentine.

Human periodontal ligament fibroblast behavior on chemically conditioned dentine: an in vitro study

BACKGROUND

Chemical root conditioning is widely used in an attempt to improve the outcome of regenerative periodontal surgery, but its effect on connective tissue cell proliferation and biosynthetic activity has been poorly studied. The goal of the present study was to test in vitro the consequences of conditioning human dentine by citric acid or minocycline on the behavior of attached human periodontal ligament (HPDL) cells in terms of proliferation, protein synthesis and morphological appearance.

METHODS

HPDL cells were seeded on powdered human dentine, either untreated or conditioned for 3 minutes with 3% citric acid or 2.5% minocycline HCI. Scanning (SEM) and transmission (TEM) electron microscopic observations were performed, and 3H-thymidine and 3H-proline incorporation tests were used to evaluate the proliferative and the biosynthetic activities.

RESULTS

Cell spreading was already evident and the penetration of cytoplasmic processes into dentinal tubules were frequently observed on all dentine types after 2 hours of attachment. After 24 hours of incubation, citric acid conditioning promoted an intense spreading of the cells, while minocycline HCI conditioning induced the formation of a dense feltwork of cellular processes. HPDL fibrolasts adherent to both types of surface-conditioned dentine exhibited a significantly higher rate of proliferation (P<0.01) as well as a significantly higher level of total protein and of collagen synthesis (P<0.01) than on untreated dentine.

CONCLUSIONS

These data suggest that during periodontal surgery a conditioning of the root surface by citric acid or by minocycline HCI could promote the attachment, the proliferation, and the biosynthetic activity of HDPL, prerequisites to periodontal regeneration.

Effect of a carbon dioxide laser on periodontally involved root surfaces

BACKGROUND

The purpose of this in vitro study was to evaluate the effect of CO2 laser on the periodontally involved root surface, and to compare its efficacy with citric acid, EDTA and hydrogen peroxide in removal of root surface smear layer after root planing.

METHODS

The study was conducted on 50 periodontally involved single rooted human teeth with poor prognosis. Immediately after extraction the teeth were scaled and root planed with Gracey curets; 50 specimens were obtained from the proximal side of each tooth which were assigned randomly to 1 of the 4 groups. Group A (35 specimens) was divided into 7 subgroups of 5 specimens each and irradiated with CO2 laser using a defocused mode at 3-watt power for 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, or 1.4 seconds, respectively. Groups B, C, and D (5 specimens each) were treated with 6% hydrogen peroxide, EDTA solution (pH 7.4), or saturated citric acid solution (pH 1), respectively for 3 minutes. The specimens were then fixed and scanned using SEM.

RESULTS

It was observed that surface smear layer was present on root surfaces of teeth that were root planed; the CO2 laser was not able to remove the smear layer on the sites that were irradiated for 0.2, 0.4 or 0.6 seconds at 3W power. Irradiation time of 0.8 seconds at 3W power was able to remove the smear layer, but the dentinal tubules were partially exposed. The surface irradiated for 1 second showed a flat appearance with many clear orifice of dentinal tubules. No change in diameter of exposed dentinal tubules was observed and their diameter was nearly equal that of normal dentinal tubules. Irradiation time of 1.2 and 1.4 seconds produced surface charring and carbonization and was totally ineffective in exposing the dentinal tubules; 6% hydrogen peroxide did not remove the smear layer completely and the exposed dentinal tubules orifice was not clear. EDTA (pH 7.4) and citric acid (pH 1) were found to be effective in removing the smear layer and exposing the dentinal tubules, which showed funnel shaped widening.

CONCLUSIONS

Surface smear layer was present on root surfaces of teeth that were root planed. Laser irradiation of 1 second at 3W completely removed the smear layer with minimal change in the diameter of the dentinal tubules. EDTA and citric acid were also effective in removing smear layer, but the exposed dentinal tubules showed funnel-shaped widening.

In vitro stimulation of human gingival epithelial cell attachment to dentin by surface conditioning

BACKGROUND

Chemical root conditioning is widely used to improve the outcome of regenerative periodontal therapies by favoring the attachment of the regenerated periodontal structures. Although the effect of root conditioning on periodontal mesenchymal cells is well documented, very little is known about its potential effect on the re-formation of the junctional epithelium, a crucial event for the protection of the wound. The goal of the present study was to test in vitro the consequences of dentin conditioning with citric acid or minocycline on the attachment kinetics and morphology of human gingival keratinocytes (HGK).

METHODS

The attachment kinetics of HGK to samples of powdered human dentin (particle size 44 to 76 microm) were examined by use of 3H-labeled cells. The morphology of attached epithelial cells was then determined by scanning electron microscopy (SEM).

RESULTS

When the initial adhesion kinetics of cells on untreated dentin were tested, the percentage of attached HGK proved to be dependent on the number of plated cells and the time of incubation (from 0 to 12 hours). Conditioning the dentin by 3% citric acid or by minocycline-HCl (at 0.01, 0.1, or 2.5%) significantly increased (P <0.005) keratinocyte attachment beyond 6 hours, without notable differences between the 2 substances at any concentration. The attachment kinetics of HGK preincubated for 24 hours by 10 microg/ml minocyline-HCl on untreated dentin was found to be similar to that observed for non-preincubated cells. These results are in agreement with the SEM observations: indeed, the surface conditioning of dentin significantly modified the morphology of attached HGK, whereas the preincubation of these cells with minocyline-HCl did not.

CONCLUSIONS

These results suggest that minocycline-HCl does not exert a direct effect on human gingival epithelial cells. In contrast, conditioning the dentin by citric acid or by minocycline stimulates the attachment of HGK, which could lead to a rapid periodontal healing by favoring the re-formation of a junctional epithelium.

Root conditioning using EDTA gel as an adjunct to surgical therapy for the treatment of intraosseous periodontal defects

The aim of this clinical study was to compare the treatment outcome following root surface conditioning using an EDTA gel preparation in conjunction with surgical therapy with that following conventional flap surgery in periodontal intraosseous defects. 36 patients, each of them contributing one intraosseous defect > or =4 mm in depth participated. Defect sites had a probing pocket depth > or =5 mm and bled on probing following hygienic treatment phase. No furcation involvement or endodontic complications were present. In the EDTA group, 18 consecutive patients, defects were treated by root conditioning with EDTA gel for 3 minutes in combination with surgical therapy. In the control group, 18 patients, conventional flap surgery was performed without root conditioning. Chlorhexidine rinsings 0.2% were prescribed following surgery for 2-3 weeks with modified oral hygiene instruction. A strict recall program was implemented including professional prophylaxis and oral hygiene reinforcement every 4-6 weeks until 6-month re-evaluation. Baseline probing pocket depths and defect depths of 7.1+/-1.3 mm and 6.9+/-1.6 mm in the EDTA group and 7.6+/-1.9 mm and 6.6+/-1.7 mm, respectively, in the control group were measured. 6-month clinical results showed a significant probing attachment level gain of 1.8+/-1.5 mm and 1.0+/-1.7 mm in the EDTA and control groups respectively. A probing bone gain of 1.0+/-1.3 mm in the EDTA group was measured with a non-significant gain of 0.4+/-1.2 mm in the control group. Radiographic analysis confirmed these results. There were no statistically significant differences in treatment outcome between the group treated by root conditioning in combination with flap surgery and conventional flap surgery alone.

In vitro modulation of human gingival epithelial cell attachment and migration by minocycline-HCL

Although the influence of tetracyclines on periodontal connective tissue cells has been the topic of many in vitro and in vivo studies, data regarding their effects on gingival epithelial cells are scarce. The present in vitro study was designed to examine the influence of minocycline, a semi-synthetic analog of tetracycline, on human gingival keratinocyte (HGK) attachment and migration. Attachment tests were performed with HGK prelabeled by tritiated amino-acids. Increasing concentrations of minocycline (10, 50, 100 micrograms/ml) in the medium produced no significant modification of cell adhesion kinetics compared to control conditions, except for 100 micrograms/ml which statistically significantly (p < 0.05) reduced the number of attached cells beyond 6 h. A 24-h cell preincubation in 10 micrograms/ml of minocycline did not alter the kinetics of HGK attachment. Scanning electron microscopic observations of attached HGK showed that the presence of 10 micrograms/ml of minocycline in the "attachment medium" induced the production of multiple filopodial extensions. Migration tests in Boyden chambers for 40 h demonstrated that HGK preincubation for 24 h in a 10 micrograms/ml minocycline-HCl solution increased significantly (p < 0.005) cell migration towards a gradient of fetal calf serum. The presence of 10 micrograms/ml of minocycline in contact with the keratinocytes in the upper compartment of the migration chambers also produced a significant (p < 0.005) result. In contrast, the presence of minocycline in the lower compartments did not produce any chemoattractive effect. Within the limits of their significance, these results suggest that, at concentrations not beyond 50 micrograms/ml, minocycline could fasten the periodontal wound coverage by epithelial cells and allow the normal reformation of a junctional epithelium.

Removal of intracanal smear by doxycycline in vitro

Cleansing and shaping result in a smear layer on the instrumented canal wall surfaces. The smear layer may inhibit close contact between sealers and dentin, and inhibits diffusion of medicaments.

OBJECTIVE

This study assessed the effect of doxycycline hydrochloride (DH) on smear layer on intracanal walls.

STUDY DESIGN

Scanning electron microscopy was used to evaluate the remaining smear layer using different concentrations of DH. Single-canal palatal roots of extracted maxillary molars were irrigated with saline-15% EDTA; saline-25 mg/ml DH; saline-50 mg/ml DH; saline-100 mg/ml DH; NaOCl-15% EDTA; NaOCl-25 mg/ml DH; NaOCl-50 mg/ml DH; and NaOCl-100 mg/ml DH. The roots were fractured into halves and the amount of smear layer assessed in the middle and apical third.

RESULTS

Doxycycline-HCl of 100 mg/ml was the most effective in removing smear layer. In the saline group, 100 mg/ml of DH was more effective than EDTA. In the hypochlorite group, 50 mg/ml and 100 mg/ml of DH were more effective than EDTA (p < 0.05).

CONCLUSION

Doxycycline solution may be an effective irrigant.

Comparative SEM study on the effect of different demineralization methods with tetracycline HCl on healthy root surfaces

Periodontal regeneration through the use of root demineralization received a lot of interest in periodontology. Topical application of acid to dentin surfaces produced a zone of demineralization, exposing dentin collagen fibrils and opening dentin tubules. In this study, the in vitro effects of different tetracycline HCl application techniques were investigated. According to the results of this SEM study, it may be desirable to apply tetracycline HCl using burnishing technique to expose maximum intertubular fibrils and for the tubular openings. However, this technique should be studied when placed in an in vivo system.

The effects of CO2, Nd:YAG and Er:YAG lasers with and without surface coolant on tooth root surfaces. An in vitro study

The objective of this study was to compare and contrast the morphologic changes in tooth root surfaces treated in vitro by scaling and root planing followed by irradiation with the Er:YAG laser using air/water surface cooling and the CO2 and Nd:YAG lasers, both with and without surface coolant. The experimental unit consisted of 42 freshly extracted teeth which were divided equally and randomly assigned to the following 7 treatment groups: untreated control, S/RP only, CO2 laser with and without air/water surface cooling, Nd:YAG laser with and without/air water surface cooling, and Er:YAG laser with air/water surface coolant. Specimens treated with CO2 laser irradiation were subjected to energy densities ranging from 100 to 400 J/cm2; those treated with the Nd:YAG from 286 to 1857 J/cm2; and the Er:YAG was used within a range of 20 to 120 J/cm2. The degree of morphologic change following CO2 and Nd:YAG irradiation appeared directly related to energy density but unrelated to the use of surface coolant. Laser induced surface changes included cavitation, globules of melted and resolidified mineral, surface crazing, and production of a superficial char layer. In contrast, the Er:YAG laser produced root surface changes that might be expected from acid etching, i.e., removal of the smear layer and exposure of the collagen matrix. In addition, sharply defined microfractures of the mineralized structure were noted and unlike the CO2 and Nd:YAG lasers, there was no evidence of melting or surface char. Given the parameters of this study, it appears that both the CO2 and Nd:YAG lasers alter the root surface in an undesirable manner. The Er:YAG laser, however, when used at low energy densities shows sufficient potential for root surface modification to warrant further investigation.

The effects of different tetracyclines on the dentin root surface of instrumented, periodontally involved human teeth: a comparative scanning electron microscope study

This in vitro study compares, by scanning electron microscope (SEM) examination, the surface effects of various topical applications of tetracycline on the instrumented dentin root surface of human teeth. Eighty-two (82) dentin samples were prepared from periodontally-compromised teeth planned for extraction. Solutions of tetracycline HCl, doxycycline, minocycline, sumycin, and a saline control were prepared and applied to the dentin samples for 0.5, 1, 3, 5, and 10 minutes. Each solution pH was measured: tetracycline HCI (pH 1.6), doxycycline (pH 2.2), minocycline (pH 3.8), sumycin (pH 4.4), and saline (pH 5.1). A tetracycline periodontal fiber was also evaluated at 1, 4, 7, and 10 days of exposure for dentin surface effects. Tetracycline HCI removed the dentin smear layer leaving clean and open tubules significantly better than other solutions tested in as little as 30 seconds. Doxycycline and minocycline produced similar results to each other, which were significantly better than sumycin and saline, but not as effective as tetracycline HCl. Smear layer removal was attained by doxycycline and minocycline in five to ten minutes; however, sumycin and the saline control ineffectively removed the surface smear layer and dentinal tubules remained partially to totally occluded by debris. The periodontal fiber did not significantly alter the surface smear layer. Results of this study suggest that tetracycline HCl is the best current tetracycline form for root surface conditioning as measured by its ability to affect both dentin smear layer removal and dentin tubule exposure.

Tetracycline demineralization of dentin: the effects of concentration and application time

The current investigation was initiated to study the effect concentration and application time has on the rate of tetracycline demineralization of dentin. Buccal and lingual surfaces of extracted bovine molars were ground to a smooth flat dentin surface using wetted silicon carbide discs. Standardized depressions were made in the dentin surface with a #909-055 diamond round wheel. Fresh tetracycline HCl (TTC-HCl) (Flavine Int. Inc.) solutions, i.e., 0, 25, 50, 75, 100, 125 and 150 mg/ml were prepared. A 30% citric acid solution was used as a positive control. The pH of each solution was recorded. 7 microl of each solution were pipetted into a depression and remained undisturbed for 1, 3, or 5 min. At the end of each application time period a fresh #3 cotton pellet was placed in the depression, once every 20 s for 1 min, to soak up the solution. The 3 pellets were placed in a 2.00 ml of 18 M omega H2O sample. As a measure of the rate of demineralization, the parts per million calcium (ppm Ca++) found in each sample were determined using atomic absorption spectrophotometry. Two-way analysis of variance was used to determine effects of TTC-HCI concentration and time on the rate of demineralization. No significant differences were found in the mean ppm Ca++ released at 1-, 3- and 5-min application times for 0, 25, or 50 mg/ml TTC. No significant differences were found in the mean ppm Ca++ released (i) between 3- and 5-min application times for 75, 100, 125 and 150 mg/ml TTC-HCl solutions and (ii) between 75, 100, 125 and 150 mg/ml TTC-HCl solutions within either the 3- or 5-min application times. The mean ppm Ca++ released at 3- and 5-min application times for 75, 100, 125 and 150 mg/ml TTC-HCI solutions were all significantly greater than the respective readings at the 1-min application time. The mean ppm Ca++ recorded for the 30% citric acid solution for all 3 application times were 3 to 5.5 x greater than the highest mean ppm Ca++ recording for TTC-HCl. The results of this study show that a 3-min application time of 75 mg/ml TTC-HCl solution is equally as effective at demineralizing dentin as is higher concentrations and/or longer application times, but was far less effective than a 30% citric acid solution.

Demineralization of resected root-ends with methylene blue dye

OBJECTIVES

This study evaluated the ability of methylene blue solutions of different concentration, pH, and time exposure to remove the smear layer from resected root-ends.

STUDY DESIGN

Resected root-ends were treated with either 2% methylene blue dye for intervals of 5 to 11 minutes or 1% methylene blue for 7 to 9 minutes and examined with a scanning electron microscope for smear layer removal. Two minute applications of saline solution and 50% citric acid served as controls.

RESULTS

All methylene blue solutions were found to be ineffective in removing the smear layer at all time intervals tested. An experimental solution of 1% methylene blue in 50% citric acid was found to predictably remove the smear layer during a 2 minute application and retained all the favorable staining characteristics of the dye. Fifty percent citric acid solutions applied for 3 minutes appeared to overdemineralize the root-end and gave poorer results than 2 minute applications.

CONCLUSIONS

Smear layer removal was pH dependent. Methylene blue solutions are clinically unsuitable for smear layer removal.

Clinical evaluation of tetracycline HCl conditioning in the treatment of gingival recessions. A comparative study

Thirty Class I and Class II recessions in 30 patients were treated with a modified subepithelial connective tissue graft procedure. Fifteen recessions in the test group received a tetracycline hydrochloride (50 mg/ml) root treatment for 5 minutes (TTC-HCl group); the remaining 15 recessions composed the control group and received a citric acid root treatment for 3 minutes (CA group). Clinical assessments were taken at baseline and at 6 months. The differences between treatments were not statistically significant. In the central area of the recession, the mean percentage of root coverage was 81.7% corresponding to a mean percentage of 79.3% and 84.0% for the TTC-HCl and the CA group, respectively. In the test group, 6 of the 15 recessions exhibited complete root coverage; the gingival augmentation was 57.8%. In the control group, 8 of the 15 recessions exhibited complete root coverage; the gingival augmentation was 43.6%. The mean surface area of root exposure was reduced from 11.53 mm2 and 13.30 mm2 to 0.34 mm2 and 0.29 mm2 for the TTC-HCl group and the CA group, respectively. This reduction corresponds to a mean percentage of 97.4% root coverage for both groups. Within the limits of this study, the results indicate that tetracycline hydrochloride and citric acid root conditioning have comparable clinical effects in root coverage surgical therapy. The data also suggest that the measurement of the surface area of the recession is a more accurate criterion in the evaluation of the mean percentage of root coverage than a single central vertical linear measurement.

Adjacent gingival recession treated with expanded polytetrafluoroethylene membranes: a report of 2 cases

We report two cases illustrating treatment for adjacent facial gingival recession using guided tissue regeneration (GTR) with expanded polytetrafluoroethylene membranes. The clinical results showed that GTR obtained soft tissue coverage of the root surfaces and was effective in reducing hypersensitivity and improving the esthetics. In both cases, satisfying clinical results have been maintained for 6 to 12 months after re-entry procedure.

Evaluation of periodontal treatments using controlled-release tetracycline fibers: clinical response

The purpose of this investigation was to evaluate the clinical efficacy of controlled-release tetracycline fiber therapy in adult periodontitis patients. One hundred-twenty-two (122) adult patients from 3 dental centers were enrolled at baseline for this study. each patient provided at least one site in each of four quadrants that was > or = 5 mm and bled on probing. One or two such sites were selected as test sites and were randomly assigned to receive one of four treatments: scaling and root planing (S), scaling and root planing plus tetracycline fiber for 10 days (SF), fiber therapy alone for 10 days (F), or two 10-day serial fiber applications (FF). After treatment, no periodontal maintenance or supportive care was provided until the end of this 12-month study. Probing depth (PD), clinical attachment level (CAL), plaque, and bleeding on probing (BOP) were measured at baseline and at 1, 3, 6, 9, and 12 months following treatment. Repeated PD and CAL measurements were taken at three locations within each site and averaged for each site. One hundred-sixteen (116) subjects completed the study. All treatments resulted in similar improvements in clinical parameters compared to baseline and were equally effective in the treatment of periodontitis as measured by probing depth reduction, clinical attachment level gain, and reduction of bleeding on probing. The clinical response, established primarily by 3 months following therapy, was generally sustained in all treatment groups for 12 months without the benefit of supportive maintenance therapy.

Evaluation of periodontal treatments using controlled-release tetracycline fibers: maintenance response

The purpose of this investigation was to examine periodontal disease recurrence from 3 to 12 months following various treatments with scaling and root planing and controlled-release tetracycline fibers. One-hundred-twenty-two (122) adult volunteers with at least one bleeding pocket > or = 5 mm in each of four quadrants were enrolled in this study. One or two such sites in each quadrant were selected as test sites. Quadrants were randomly assigned to receive one of four treatments: scaling and root planing (S); scaling and root planing plus tetracycline fiber for 10 days (SF); fiber therapy alone for 10 days (F); or fiber therapy alone for 20 days (FF). After treatment, no supportive care was provided during the 12-month study period. Probing depth (PD), attachment loss (AL), plaque, and bleeding on probing were measured at baseline, and at 1, 3, 6, 9, and 12 months after treatment. PD and AL measures were taken at three locations within each site and averaged for each site. Disease recurrence was defined as > or = 1 mm mean attachment loss at a site during the 3- to 12-month period. One-hundred-sixteen (116) subjects completed the study. Sites treated with SF experienced significantly (P < 0.05) less disease recurrence (4%) than S, F, or FF (9%, 10%, and 12%, respectively). Results of this study suggest that, compared to S, F, or FF, scaling and root planing in conjunction with tetracycline fiber therapy for 10 days can significantly reduce disease recurrence 3 to 12 months following treatment in the absence of supportive care.

Effects of citric acid treatment on the Ca, P and Mg contents of human dental roots

An electron microprobe analyser associated with a scanning electronic microscope was used to measure Ca, P and Mg contents of the human dental root hard tissues, before and after a citric acid treatment (pH = 1). The measurements were made on transverse sections through the cervical 1/3 of the molar roots. The measurements were performed at the following 8 levels: the internal cementum, the cementum-dentine junction, cementum-related dentine, 4 external dentine levels located at 220 microns, 420 microns, 620 microns and 820 microns from the cementum-dentine junction, and finally the juxta-pulpal dentine. After the citric acid treatment, the losses in Ca and P, but not in Mg, varied significantly with the level; an acid-resistant dentine layer of approximately 600 microns was found under the cementum-dentine junction. An increase in the Ca/P ratio was also observed in this layer. Since this external dentine zone is less demineralized by the citric acid than the underlying dentine, the collagen matrix in this region may also be less exposed. These differences in the response to citric acid that depend on the distance from the root surface may explain the unpredictability of periodontal healing after citric acid treatment of diseased root surfaces, because the amount of tissue removed during root planing is not constant.

Root surface texture and early cell and tissue colonization after different etching modalities

The purpose of the present study was to compare the texture of dentin surfaces after etching with citric and phosphoric acids as well as EDTA with respect to mode of application and exposure time, and to assess possible effects on early cell and tissue colonization. It was concluded that EDTA operating at neutral pH was able to selectively remove mineral from a dentin surface, exposing a collagenous matrix. This was in contrast to etching with citric and phosphoric acids, both of which operate at a low pH. They both appeared to remove not only the mineral component but also the collagenous matrix. EDTA-treated dentin surfaces, compared to surfaces etched at low pH, appeared to be more inviting for cellular colonization and subsequent connective tissue formation. The reason for this may have been twofold: Dentin surfaces etched with an etching agent operating at neutral pH, as indicated above, retain more exposed collagen fibers than dentin surfaces etched at low pH. Furthermore, it can not be excluded that a low pH etching agent necrotized an area of the periodontal ligament in the immediate vicinity of the denuded dentin surfaces.

Effects of tetracycline-containing gel and a mixture of tetracycline and citric acid-containing gel on non-surgical periodontal therapy

The purpose of this study was to assess the clinical and microbiological effects of a newly developed root conditioning gel system containing tetracycline or a mixture of tetracycline and citric acid on non-surgical periodontal therapy. Sixty-four (64) single-rooted teeth with a probing depth of 4 to 6 mm were randomly subjected to one of the following four treatments; 1) root planing alone (RP group); 2) tetracycline-containing gel alone (TCG group); 3) root planing plus tetracycline-containing gel (RP + TCG group); or 4) root planing plus a mixture of tetracycline and citric acid-containing gel (RP + TC-CAG group). Probing depth, attachment level, and tooth mobility were measured and the presence of dental plaque and gingival inflammation was recorded at baseline and after 2, 4, 8, and 12 weeks. Subgingival plaque samples from each site were collected at the same visits and examined with phase contrast microscopy for proportions of motile rods and spirochetes. Plaque index, gingival sulcus bleeding index (SBI), probing depth, and attachment level decreased significantly in all groups compared to the baseline values (P < 0.05). A significant decrease in probing pocket depth was noted after 12 weeks in RP + TC-CAG group compared to the other groups (P < 0.05). Significantly more gain in attachment was detected in the RP + TC-CAG group compared to the TCG group (P < 0.05). Tooth mobility scores also decreased later in the study. A significant decrease in the proportion of motile rods was found primarily in the RP + TC-CAG group.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of root conditioning with minocycline HCl in removing endotoxin from the roots of periodontally-involved teeth

Noting the acid-conditioning effect of minocycline on the root surface, we investigated the ability of minocycline to remove endotoxin on untreated, diseased cementum in vitro. Root surface specimens affected by periodontal disease were immersed in minocycline solution (10 mg/ml, 50 micrograms/ml, and 5 micrograms/ml) for 10 minutes, 1 day, 3 days, and 7 days, and endotoxin eluted was determined by the limulus amoebocyte lysate (LAL) assay. Specimens serving as controls were treated by immersion in pyrogen-free water, agitation, polishing, or exposure to citric acid (pH 1.0) for 3 minutes. When the period of immersion was the same, the root treatment with minocycline (10 mg/ml) yielded a significantly higher rate of neutralization of endotoxin than that with a 5 micrograms/ml or 50 micrograms/ml solution. However, the detoxifying effect of this method was less adequate than that of polishing or treatment with citric acid solution. There was variability in the effects of polishing among the teeth tested. To obtain the expected effect of the root treatment with minocycline solution; i.e., removal of the endotoxin, the combining of minocycline with a mechanical root preparation, such as polishing or root planing, seems to be effective.

Comparative SEM study on the effect of acid etching with tetracycline HCl or citric acid on instrumented periodontally-involved human root surfaces

This study compared the surface characteristics of periodontally diseased single-rooted human teeth extracted after treatment with either tetracycline HCl or citric acid solutions. The study group was comprised of 30 teeth from 22 patients with advanced periodontal disease extracted before the start of periodontal therapy. Diseased surfaces were identified, outlined, and root planed by hand curet or finishing bur. The teeth were sectioned and solutions of tetracycline HCl or citric acid (pH 1) were applied to the surfaces with cotton pellets for 5 minutes. Extracted teeth were processed and root surface samples then examined by scanning electron microscope. The surfaces of both acid-treated sets of specimens differed considerably from specimens treated with root planing alone, regardless of root planing method. Acid-treated specimens exhibited dentinal tubules exposed by the removal of the smear layer, surfaces devoid of the debris normally present in root planed-only specimens, and the dense network of collagen fibers that make up the dentin structure. Although differences were seen in surface depressions and fiber-like structures among some specimens, the tetracycline HCl and citric acid solutions produced comparable morphologic characteristics.

Annual review of selected dental literature: report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The annual review of selected dental literature this year cites 384 published papers and reports. This year's review contains more editorial comment than reviews of years passed. New data on the biological responses to materials is emphasized in several sections. Observations on new compounds able to prevent plaque formation are presented. Clinically relevant advances in knowledge concerning the etching of different tooth structures are reported along with the effect of etching procedures on the dental pulp. Evaluation of periodontal diseases in all age groups is a topic. Limitations of current diagnostic techniques in periodontal disease, temporomandibular disorders, and implant therapy are included. There are new views on the use of dental amalgam. The future use of dental mercury is predicted. Interest in new ceramic systems is indicated as the demand for esthetics continues. Clinical information is emphasized over scientific information throughout this year's review.