A biochemical approach to periodontal regeneration: tetracycline treatment of dentin promotes fibroblast adhesion and growth

Effects of Curcumin and Tetracycline Gel on Experimental Induced Periodontitis as an Anti-Inflammatory, Osteogenesis Promoter and Enhanced Bone Density through Altered Iron Levels: Histopathological Study

Adjunctive use of antimicrobials with scaling and root planing (SRP) is necessary to better eradicate dental biofilm. Tetracycline (T) is the most commonly used antimicrobial; however, it has limitations. This study evaluates the effect of curcumin (CU) as adjunct to SRP on inflammatory markers, collagen fiber deposition, and altered iron level. A total of 32 Wistar rats were divided into five groups: no experimental periodontitis (healthy control), experimental periodontitis (EPD), EPD treated with SRP alone (SRP), EPD treated with SRP+T (SRP+T), and EPD treated with SRP+CU (SRP+CU). After 2 and 4 weeks of treatment, tissue samples were assessed by hematoxylin and eosin, and special stains (Perls’ stain and Masson’s Trichrome) for counting of inflammatory cells, angiogenesis, collagen fibers, and iron deposition. Significant reductions in inflammatory cells infiltration and alveolar bone resorption with angiogenesis and collagen fibers deposition were detected after 2 and 4 weeks in both SRP+T and SRP+CU groups. SRP+CU resulted in a significant reduction in osteoclast numbers (week 2) and iron deposition (week 4) in bone trabeculae as compared to SRP and SRP+T groups. The adjunctive use of CU showed comparable results to T in the reduction in inflammation and bone resorption. Furthermore, CU has potential osteogenesis and healing effects.

In vitro assessment of the antimicrobial activity of tetracycline hydrochloride diluted in three different vehicles against Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum

Background:

The development and progression of periodontal diseases is a result of the dynamic interaction of microorganisms within their habitat, and changes in this habitat generate a dysbiotic state. Fusobacterium nucleatum and Prevotella intermedia are bridging microorganisms between the pioneer communities and other microorganisms responsible for periodontitis such as Porphyromonas gingivalis. Tetracycline hydrochloride (TTC-HCl) is commonly used as a coadjutant in periodontal treatment in the form of an antiseptic. However, there are no clear dilution or concentration protocols.

Objective:

This study aimed to evaluate the in vitro antimicrobial activity of TTC-HCl diluted in sterile water, saline solution, and 2% lidocaine with epinephrine 1:80,000 at concentration of 125, 250, and 500 mg, at three time points– 30, 60, and 120 s – on P. intermedia, F. nucleatum, and P. gingivalis using the Kelsey–Maurer technique.

Materials and Methods:

The antimicrobial activity of TTC-HCl was evaluated at the proposed concentrations and times, dissolved in the different vehicles at pH 1.9 and 7.0, on F. nucleatum, P. intermedia, and P. gingivalis. The Kelsey–Maurer test was used to verify the presence or absence of colony-forming units. Each test was performed in triplicates with its respective viability controls.

Results:

Inhibition of F. nucleatum, P. intermedia, and P. gingivalis was achieved with TTC-HCl at all concentrations, dissolved in distilled water, saline solution, and 2% lidocaine with epinephrine 1:80,000 for all times.

Conclusions:

The results show that TTC-HCl is a good antimicrobial alternative against F. nucleatum, P. intermedia, and P. gingivalis regardless of the vehicle in which it was dissolved, concentration, pH, or time used in this investigation.

Effect of tetracyclines on pulpal and periodontal healing after tooth replantation: a systematic review of human and animal studies

Background

Pulpal and periodontal healing are two main concerns of delayed replantation of avulsed teeth. The objective of this review was to evaluate the effectiveness of topical and systemic application of tetracyclines on pulpal and periodontal healing after tooth replantation.

Methods

A comprehensive electronic search was conducted in six databases. This systematic review was carried out according to Cochrane Handbook and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results

After exclusion of 246 irrelevant papers, 14 animal studies and one human study were included in this review. The human study showed that avulsed permanent teeth treated with doxycycline did not show a better clinical outcome for pulp and periodontal healing compared with treatment with normal saline. As for animal studies, significant more pulpal healing was observed in immature teeth treated with topical doxycycline in two researches, while another one study showed that there is no difference between teeth treated with normal saline and teeth treated with doxycycline. Systemic doxycycline exerted no significant effect on pulpal revascularization illustrated by one research. Only one out of four articles illustrated the positive effect of systemic tetracyclines on periodontal healing. One paper reported that intracanal application of demeclocycline promoted favorable periodontal healing. Two articles showed topical doxycycline contributed to favorable periodontal healing, while five studies showed no significant effect of topical tetracyclines on periodontal healing.

Conclusions

As a result of data heterogeneity and limitations of the studies, the effect of topical or systemic application of tetracyclines on pulpal and periodontal healing is inconclusive. More studies are required to get more clinically significant conclusions.

A bibliometric study of the top cited papers related to periodontal regeneration

This report identifies the top cited papers in the field of periodontal regeneration since inception of the concept. Using the H-classics approach, 132 papers published between 1970 and 2012 were identified, with 230.0 ± 175.6 (mean ± SD) citations and 10.4 ± 11.5 citations/year. There were 46 clinical reports, 28 animal studies, 23 in vitro studies, 30 reviews, 3 systematic reviews, and 2 combined animal and in vitro studies. Analysis of covariance showed that institution number (≥3, P = 0.011), journal impact factor at publication (>3.0, P = 0.001) and study type (in vitro/reviews vs. clinical trials/animal studies, P = 0.024) were significantly associated with citations/year. This study has characterized the most influential literature in the field of periodontal regeneration and serves as a quick reference resource.

Inhibitory effects on Streptococcus mutans of antibacterial agents mixed with experimental fluoride varnish

We investigated the inhibitory effect of antibacterial agents mixed with experimental fluoride varnish (EFV) on Streptococcus mutans. The antibacterial agents used were (1 and 10) mM of xanthorrhizol, bakuchiol, bavachalcone, isobavachromene, and bavachromene. Agar diffusion tests were performed on S. mutans (1.1×10¹⁰ CFU/mL), using antibacterial agents without and with EFV. Bavachalcone showed the highest inhibition zone without and with EFV at both (1 and 10) mM (p<0.05). All EFV with antibacterial agents showed greater inhibition and semi-inhibition zones than EFV alone (p<0.05). The cell viability of each antibacterial agent was not significantly different from the vehicle controls (p>0.05), except xanthorrhizol and bakuchiol at 1 mM. All antibacterial agents were effective, while antibacterial agents with EFV co-formulations were more effective than EFV alone. Bavachalcone was the most effective agent against S. mutans, indicating its potential usefulness with fluoride varnish in preventing dental caries.

Calcium sulfate combined with guided tissue regeneration: A novel technique in treatment of gingival recessions

The presence of mucogingival problem around anterior teeth is a challenge to the clinician as not only biological and functional aspects has to be addressed but esthetic aspirations of the patient have to be met. The use of guided tissue regeneration (GTR) procedures for the treatment of gingival recession has shown encouraging results and is gaining clinical acceptance. However, maintenance of space under the membrane remains a problem for clinicians. Hence, this case study was an innovative attempt to evaluate the effect of adjunctive calcium sulfate placement along with collagen membrane GTR-based root coverage procedure.

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.

Biological Effects of a Root Conditioning Treatment on Periodontally Affected Teeth - An In Vitro Analysis

Abstract The aim of this study was to evaluated the root surfaces modifications resulted by application of different chemicals agents, and their influence on the fibrin network and fibroblasts attachment. From 96 anterior mandibular human extracted incisor teeth, 192 dentin blocks of buccal and lingual surface were obtained and randomly divided into 6 groups: Cont- control group, which received no treatment; Root surface scaling and root planing (Srp); Citric acid-Srp; EDTA-Srp; Tetracycline capsule-Srp; Tetracycline gel-Srp. After dentin treatments the specimens were analyzed as follows: 1) demineralization level and residues of the product by scanning electron microscopy (SEM); 2) adhesion of blood components after 20 min of surface treatment by SEM; 3) fibroblast attachment after 24 h by SEM; 4) cell metabolism after 24 h by MTT assay. Data were analyzed using Fisher Exact, One-way ANOVA test followed by Dunn's test, Tukey test and Dunnett test (α=0.05). Citric acid, EDTA and Tetracycline gel resulted in adequate demineralization with no completely smear layer and smear plug removal on root dentin surface. Tetracycline capsule produced great tetracycline residues with several demineralization areas. Tetracycline gel and EDTA groups presented more fibroblast fixation than other experimental groups. The highest mean blood clot adhesion score was observed in roots treated with tetracycline gel. EDTA and Tetracycline gel surface treatment removed the smear layer over dentin surface and promoted adhesion of fibrin network and fibroblast cells attachment.

Management of Root Resorption Using Chemical Agents: A Review

Root resorption (RR) is defined as the loss of dental hard tissues because of clastic activity inside or outside of tooth the root. In the permanent dentition, RR is a pathologic event; if untreated, it might result in the premature loss of the affected tooth. Several hypotheses have been suggested as the mechanisms of root resorption such as absence of the remnants of Hertwig's epithelial root sheath (HERS) and the absence of some intrinsic factors in cementum and predentin such as amelogenin or osteoprotegerin (OPG). It seems that a barrier is formed by the less-calcified intermediate cementum or the cementodentin junction that prevents external RR. There are several chemical strategies to manage root resorption. The purpose of this paper was to review several chemical agents to manage RR such as tetracycline, sodium hypochlorite, acids (citric acid, phosphoric acid, ascorbic acid and hydrochloric acid), acetazolamide, calcitonin, alendronate, fluoride, Ledermix and Emdogain.

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.

Root conditioning in periodontology - Revisited

OBJECTIVE

Root surfaces of periodontitis-affected teeth are hypermineralized and contaminated with cytotoxic and other biologically active substances. To achieve complete decontamination of the tooth surfaces, various methods including root conditioning following scaling and root planning are present. The main objective of this article is to throw light on the different root conditioning agents used and the goals accomplished by root conditioning in the field of periodontology.

MATERIALS AND METHODS

20 human maxillary anterior teeth indicated for extraction due to chronic periodontitis were collected and root planned. The teeth were sectioned and specimens were divided into two groups - Group I and II. Group I dentin specimens were treated with EDTA and group II specimens were treated with tetracycline HCl solution at concentration of 10% by active burnishing technique for 3 minutes. The root surface samples were then examined by scanning electron microscope (SEM).

RESULTS

The results of the study showed that EDTA and tetracycline HCl were equally effective in removing the smear layer. It was observed that the total and patent dentinal tubules were more in number in teeth treated with tetracycline as compared to EDTA group. However, EDTA was found to be much more effective as root conditioning agent because it enlarged the diameter of dentinal tubules more than that of tetracycline HCl.

CONCLUSION

Results of in-vitro study showed that both the agents are good root conditioning agents if applied in addition to periodontal therapy. However, further studies are required to establish the in-vivo importance of EDTA and tetracycline HCL as root conditioners.

Comparative evaluation of decalcified freeze dried bone allograft with and without local doxycycline in non-contained human periodontal infrabony defects

BACKGROUND

Doxycycline has been advocated as useful adjuncts in periodontal therapy not only due to their antimicrobial actions, but also to their recently recognized anti-collagenolytic, anti-inflammatory, osteoclast inhibitory and fibroblast stimulating property. The purpose of the present cohort study was to evaluate the regenerative outcomes of bone graft with or without local doxycycline in non-contained infrabony periodontal defects.

MATERIALS AND METHODS

16 one or two wall infrabony defects, in 11 patients suffering from moderate to severe chronic periodontitis, aged 35-60 years, were randomly divided for bone graft, alone (control) and with doxycycline (test) for the study. At baseline, after 3 months and after 6 months of post-operative period, pocket probing depth (PPD), clinical attachment level (CAL), radiological bone fill (RBF) and alveolar height reduction were recorded. Analysis of variance and Newman-Keuls post-hoc test were used or statistical analysis. A two-tailed probability (P) value P < 0.05 was considered to be statistically significant.

RESULTS

For the control group PPD reduction 2.00 ± 0.18 mm, CAL gain 1.38 ± 0.17 mm, RBF 0.63 ± 0.27 mm (18.0%) was observed while in the test group PPD reduction 2.00 ± 0.38 mm, CAL gain 1.25 ± 0.31 mm, RBF 0.75 ± 0.31 mm (20.7%) was evaluated. While alveolar height reduction for the control group and test group was 13% and 12.5% respectively.

CONCLUSION

The study confirmed no added benefits of local doxycycline, as compared with bone graft alone, for regeneration of non-contained human periodontal infrabony defects.

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.

Evaluation of the effect of allograft with doxycycline versus the allograft alone in the treatment of infrabony defects: A controlled clinical and radiographical study

BACKGROUND

Successful prevention and treatment of periodontal disease are contingent on effective control of periodontopathic microbiota based on the premise of periodontal disease being infectious disorders. An anti-microbial agent, i.e., doxycycline has been incorporated into the allograft to control infection and facilitate healing during and after periodontal therapy.

MATERIALS AND METHODS

Using a split-mouth design, 15 patients showing clinical evidence of almost identical bilateral infrabony defects requiring bone grafting procedures were randomly selected. In each patient, infrabony defects on one side were designated as Group A (control group) and infrabony defects of the contralateral side of the same arch were designated as Group B (test group). Clinical assessment of probing pocket depth and attachment level and radiographic evaluation of the defect depth was done pre-operatively and at 12-week and 24-week post-operatively. The relative efficacy of the two treatment modalities was evaluated using paired Student's t-test and the comparative evaluation between the two groups over the 3 time intervals was done using independent Student's t-test.

RESULTS

Both the groups exhibited a highly significant reduction in probing depth and gain in clinical attachment level (CAL) and a linear bone fill at the end of 12 and 24 weeks. Comparative evaluation showed a statistically significant gain in bone fill in Group B as compared to Group A, whereas a non-significant reduction in probing depth and gain in CALs between the two groups at the end of 24 weeks (whereas mean reduction in probing depth and gain in CAL were also greater in Group B but the difference was statistically non-significant).

CONCLUSION

The increase in linear bone fill in Group B signifies the role of doxycycline in augmenting regenerative potential of allograft by combating residual infection and through host modulation.

Influence of concentration, time and method of application of citric acid and sodium citrate in root conditioning

Objective

The aim of this study was to establish the parameters of concentration, time and mode of application of citric acid and sodium citrate in relation to root conditioning.

Material and Methods

A total of 495 samples were obtained and equally distributed among 11 groups (5 for testing different concentrations of citric acid, 5 for testing different concentrations of sodium citrate and 1 control group). After laboratorial processing, the samples were analyzed under scanning electron microscopy. A previously calibrated and blind examiner evaluated micrographs of the samples. Non-parametric statistical analysis was performed to analyze the data obtained.

Results

Brushing 25% citric acid for 3 min, promoted greater exposure of collagen fibers in comparison with the brushing of 1% citric acid for 1 minute and its topical application at 1% for 3 min. Sodium citrate exposed collagen fibers in a few number of samples.

Conclusion

Despite the lack of statistical significance, better results for collagen exposure were obtained with brushing application of 25% citric acid for 3 min than with other application parameter. Sodium citrate produced a few number of samples with collagen exposure, so it is not indicated 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.

Experimental periodontal disease treatment by subgingival irrigation with tetracycline hydrochloride in rats

Objective

The aim of this study was to compare subgingival irrigation with tetracycline hydrochloride (TTC-HCL) as adjunctive treatment to scaling and root planning (SRP) on induced periodontitis in rats.

Material and methods

In 60 rats, periodontal disease was ligature-induced at the mandibular left first molar. After 7 days, the ligature was removed and all animals were submitted to SRP, and divided into 2 groups according to the following treatment: C (n=30) - subgingival irrigation with 1 mL of saline; T (n=30) - subgingival irrigation with 1 mL of TTC-HCL (50 mg/mL). Ten animals in each group were euthanized at 7, 15 and 30 days posttreatment. The histometric values were statistically analyzed (p<0.05).

Results

In the histometric analysis, at 7, 15 and 30 days, Group T (0.72±0.05 mm², 0.57±0.14 mm², 0.62±0.07 mm²), showed less bone loss (p<0.05) than Group C (1.35±0.25 mm²; 1.40±0.31 mm²; 1.29±0.27 mm²), respectively.

Conclusions

Subgingival irrigation with TTC-HCL was an effective adjunctive treatment for periodontal disease induced in rats.

Removal of intracanal smear layer by doxycycline: SEM analysis

The aim of this study was to verify the efficacy of doxycycline used alone or in association with sodium hypochlorite on smear layer removal. The canals of extracted human teeth were instrumented using a stepback technique. At the end of preparation, they were irrigated with doxycycline (Group 1), ethylenediaminetetraacetic acid + sodium hypochlorite (Group 2), doxycycline + sodium hypochlorite (Group 3) and water (Group 4). The dentinal wall of the cervical, middle and apical thirds was graded according to the amount of remaining debris and smear layer. The results were analysed using the Kruskal-Wallis test (P < 0.05). In Groups 2 and 4, the dentine was completely free and covered with smear layer, respectively. The results from the cervical and middle thirds of Group 3 were worse than those in Groups 1 and 2 (P < 0.05). In relation to apical third, there were differences (P < 0.05) between all groups with best results for Group 2. Doxycycline was effective in removing smear layer from cervical and middle thirds. The use of doxycycline + sodium hypochlorite was partially effective in the cervical and middle thirds, but ineffective in the apical third.

Root surface conditioning in closed apex avulsed teeth: a clinical concept and case report

In an avulsed tooth with an open apex, a recommended procedure is to coat the root surface with topical doxycycline before reimplantation. Doxycycline, a derivative of the tetracycline family, has an antibacterial effect and anti-inflammatory qualities, and is effective in reducing inflammatory and replacement resorption following dental trauma. Treating the root surface of an avulsed closed apex tooth is a rational and recommended procedure. A case is presented in which an avulsed closed apex tooth, conditioned with topical doxycycline, was reimplanted in the socket. At follow-up, 16 months later, no clinical signs and symptoms were present and radiographic evaluation showed only superficial root surface resorption and an intact PDL.

Effect of absorbent tetracycline-loaded membrane used in the reduction of periodontal pockets: an in vivo study

This clinical study evaluated the influence of scaling and root planning (SRP), with and without the use of tetracycline-loaded bovine absorbent membrane, in the reduction of periodontal pockets according to 3 parameters: probing pocket depth (PPD), bleeding on probing (BOP) and plaque index (PI). Twenty-four patients were selected totalizing 144 random teeth divided in 2 groups (n=72 teeth) - control (SRP) and experimental (SRP with tetracycline-loaded absorbent membrane). PPD, BOP and PI were determined before and 28 days after the treatment. In all patients, the PPD values at the end of the treatment were always lower than the baseline values. There was a reduction of the PI for both treatments, but it was more evident on the experimental group. In conclusion, the use of tetracycline-loaded absorbent membrane could result in a better prognosis compared to scaling and root planning after only 28 days of evaluation.

Effects of basic fibroblast growth factor on density and morphology of fibroblasts grown on root surfaces with or without conditioning with tetracycline or EDTA

A study was conducted to evaluate in vitro the effect of root surface conditioning with basic fibroblast growth factor (b-FGF) on morphology and proliferation of fibroblasts. Three experimental groups were used: non-treated, and treated with 50 microg or 125 microg b-FGF/ml. The dentin samples in each group were divided into subgroups according to the chemical treatment received before application of b-FGF: none, or conditioned with tetracycline-HCl or EDTA. After contact with b-FGF for 5 min, the samples were incubated for 24 h with 1 ml of culture medium containing 1 x 10(5) cells/ml plus 1 ml of culture medium alone. The samples were then subjected to routine preparation for SEM, and random fields were photographed. Three calibrated and blind examiners performed the assessment of morphology and density according to two index systems. Classification and regression trees indicated that the root surfaces treated with 125 microg b-FGF and previously conditioned with tetracycline-HCl or EDTA presented a morphology more suggestive of cellular adhesion and viability (P = 0.004). The density of fibroblasts on samples previously conditioned with EDTA, regardless of treatment with b-FGF, was significantly higher than in the other groups (P < 0.001). The present findings suggest that topical application of b-FGF has a positive influence on both the density and morphology of fibroblasts.

New emphasis in the treatment of dental trauma: avulsion and luxation

There are several protocols for the successful management of dental trauma emergencies. However, these existing protocols are inconsistent regarding several issues. As the Israeli dental community and patients have specific characteristics, a modified and adaptable protocol was required. This new protocol contains simple and straightforward clinical guidelines, arranged in table format, according to the nature of the trauma. The present study shows the protocol for luxation and avulsion injuries, with new recommendations for the treatment of luxated closed-apex teeth, the preferred at-site treatment and storage medium for avulsed teeth, and the conditioning of the root surface in these cases. To emphasize and explain the modification of this new protocol, research-based information has been incorporated.

Effect of Er:YAG Laser Combined With rhPDGF-BB on Attachment of Cultured Fibroblasts to Periodontally Involved Root Surfaces

BACKGROUND

The use of the erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser in periodontal therapy has been the focus of much research. Recombinant human platelet-derived growth factor-BB (rhPDGF-BB) is suggested as a potent stimulator and strong mitogen for human periodontal ligament cells. The present study tested the direct effects of Er:YAG laser irradiation, alone or with rhPDGF-BB application, on the biocompatibility of periodontally diseased roots through fibroblast attachment and proliferation.

METHODS

The study examined five healthy and 15 periodontally involved teeth, prepared from proximal surfaces, which were divided randomly into four groups (10 specimens each): group 1: healthy; group 2: untreated diseased; group 3: Er:YAG laser irradiation (60 mJ/pulse, 10 Hz); and group 4: Er:YAG laser irradiation (60 mJ/pulse, 10 Hz) plus rhPDGF-BB application (50 ng/ml). Three subgroups per group (three specimens each) were incubated for three periods (1, 3, or 7 days). The remaining specimen was used to determine surface topography. Fibroblasts were pooled on root specimens and incubated. Results were evaluated using scanning electron microscopy. Repeated cell counts were performed within a representative standard area.

RESULTS

Using paired t tests, all experimental groups (except group 2 diseased) showed statistically significant differences between 1- and 3-day and between 1- and 7-day incubation periods, but not between 3- and 7-day incubation periods. Using analysis of variance, the intergroup comparison showed significant differences favoring group 1 over groups 2 and 3 and group 4 over group 2 at the 1-day incubation period; group 1 was favored over groups 2, 3, and 4 and groups 3 and 4 were favored over group 2 at the 3- and 7-day incubation periods. Comparable effects were shown between groups 3 and 4 for all incubation periods and between groups 2 and 3 and groups 1 and 4 for the 1-day incubation.

CONCLUSIONS

Er:YAG laser used alone or in combination with rhPDGF-BB application may offer a promising periodontal therapy for conditioning root surfaces, although the combined application seemed to be slightly more effective. However, testing laser use in intervals and with parameters <60 mJ/pulse and 10 Hz is required to verify the minimum threshold values necessary to obtain complete root debridement and clarify optimal conditions for fibroblast cell attachment and growth. Further studies are needed to determine ideal parameters for creating the best environment for successful periodontal treatment.

Position Paper: Periodontal Regeneration

Untreated periodontal disease leads to tooth loss through destruction of the attachment apparatus and tooth-supporting structures. The goals of periodontal therapy include not only the arrest of periodontal disease progression,but also the regeneration of structures lost to disease where appropriate. Conventional surgical approaches (e.g., flap debridement) continue to offer time-tested and reliable methods to access root surfaces,reduce periodontal pockets, and attain improved periodontal form/architecture. However, these techniques offer only limited potential towards recovering tissues destroyed during earlier disease phases. Recently, surgical procedures aimed at greater and more predictable regeneration of periodontal tissues and functional attachment close to their original level have been developed, analyzed, and employed in clinical practice. This paper provides a review of the current understanding of the mechanisms, cells, and factors required for regeneration of the periodontium and of procedures used to restore periodontal tissues around natural teeth. Targeted audiences for this paper are periodontists and/or researchers with an interest in improving the predictability of regenerative procedures. This paper replaces the version published in 1993.

Glycosylation Pattern and Cell Attachment-Inhibiting Property of Human Salivary Mucins

BACKGROUND

Whole human saliva (WHS) and its high molecular weight mucin constituent (Muc) inhibit fibroblast attachment and might influence periodontal and peri-implant wound healing. The aim of this work was to study the potential role of glycosylation of Muc in fibroblast attachment-inhibiting property and to examine in vitro the effect of WHS and Muc on epithelial cell attachment.

METHODS

Muc was isolated from WHS by CsCl density gradient ultracentrifugation; covalently immobilized on polystyrene; and subjected to enzymic digestion by N-glycanase, O-glycanase, and sialidase, or chemical desulfation and periodate treatment. Wells of tissue culture microtiter plates were incubated with WHS, Muc, or buffer as control; suspensions of normal human oral keratinocytes, spontaneously immortalized human keratinocytes, or human gingival fibroblasts were applied; and cell attachment determined using methylene blue assay.

RESULTS

While enzymic cleavage of N-linked carbohydrates showed no effect, selective removal of O-linked residues and sialic acid as well as desulfation and periodate oxidation resulted in statistically significant reduction of cell attachment-inhibiting property of immobilized Muc. Significantly lower numbers of attached cells of each cell type were found in wells pretreated with WHS or Muc.

CONCLUSIONS

Inhibition of cell attachment may be mediated by the carbohydrate residues suggesting specific interactions between the salivary constituent and the cell surface. Exposure of root and implant surfaces to saliva during early wound healing events might influence healing by inhibiting surface colonization by oral keratinocytes and fibroblasts, and enhancing wound repair in the form of long junctional epithelium rather than regeneration.

The combined use of enamel matrix proteins and a tetracycline-coated expanded polytetrafluoroethylene barrier membrane in the treatment of intra-osseous defects

OBJECTIVES

The purpose of this split-mouth study was to evaluate the clinical response of enamel matrix proteins (EMPs, Emdogain Gel in intra-osseous defects with or without a combined application of a tetracycline-coated expanded polytetrafluoroethylene barrier membrane (e-PTFE, Gore-Tex).

METHODS

Twelve pairs of intra-osseous periodontal defects in 11 patients received the application of EMPs on the exposed root surface (EMP). One of the two defects received randomly, as an adjunct to EMP treatment, a tetracycline-coated e-PTFE membrane (MEMP). At baseline, 6- and 12-month probing pocket depth (PPD), clinical attachment level (CAL) and probing bone level (PBL) were measured.

RESULTS

After 12 months, the EMP defects showed a significant mean PPD reduction of 2.86+/-0.75 mm, a mean gain in CAL of 1.28+/-2.04 mm, a mean PBL gain of 1.63+/-1.21 mm and a mean increase of recession (REC) of 1.56+/-2.30 mm. The MEMP defects showed a significant mean PPD reduction of 3.02+/-1.55 mm, a mean gain in CAL of 1.65+/-1.29 mm, a mean PBL gain of 1.58+/-1.92 mm and a mean increase of REC of 1.38+/-1.63 mm. Except for significantly more post-operative discomfort at the MEMP sites, no significant differences were found between EMP and MEMP defects.

CONCLUSION

Within the limits of this study, it is concluded that in the treatment of intra-osseous defects with EMP, the adjunctive use of a tetracycline-coated e-PTFE membrane failed to show more gain of CAL and PBL.

Tetracycline at Subcytotoxic Levels Inhibits Matrix Metalloproteinase-2 and -9 But Does Not Remove the Smear Layer

BACKGROUND

The antibacterial and anticollagenolytic properties of tetracycline (TCN) are valuable in periodontal therapy, and TCN treatment can remove the smear layer following root instrumentation. However, recent reports pointing to cytotoxic effects of several acids prompted this study to define TCN concentrations that are anticollagenolytic and remove the smear layer, but have low cytotoxicity.

METHODS

Human gingival (hGF) and periodontal ligament (hPDL) cells were treated short- (3 minutes) or long-term (24 hours) with TCN to determine concentrations yielding 50% (TD(50)) and 90% (TD(10)) cell survival. Activity assays measured TCN concentrations with half-maximal inhibition (IC(50)) of matrix metalloproteinase- 2 and -9 (MMP-2 and -9). Finally, we analyzed the effects of TCN with high (75 mg/ml) or low (1 mg/ml) cytotoxicity on the smear layer by scanning electron microscopy (SEM).

RESULTS

The TD(50) for TCN after short-term treatment was 4 mg/ml for both hGF and hPDL. Ninety percent of the cells survived 0.2 mg/ml. With long-term treatment, the TD(50) for hGF and hPDL was 70 and 30 microg/ml, respectively, and the TD(10) was 20 and 5 microg/ml. HGF and hPDL recovered from the 3-minute treatment with 1 mg/ml, but not from concentrations exceeding 3 and 9 mg/ml, respectively. The IC(50) was 25 microg/ml for both MMP-2 and MMP-9. Whereas 75 mg/ml TCN removed the smear layer, 1 mg/ml TCN had no effects.

CONCLUSIONS

Tetracycline has significant cytotoxicity on periodontal cells. Since non-cytotoxic concentrations of TCN inhibited MMP-2 and -9 but had no effects on the smear layer, TCN is not recommended for root surface treatment.

Healing of Dehiscence Defects Following Root Surface Demineralization With Tetracycline: A Histologic Study in Monkeys

BACKGROUND

The purpose of this study was to histologically evaluate the healing of experimental dehiscence defects after surface demineralization with tetracycline hydrochloride.

METHODS

Six adult male monkeys (Cebus apella) were used in this study. Dehiscence defects were surgically created on the buccal aspect of the mandibular lateral incisors in all animals. The root surfaces were debrided and planed. In a split-mouth design, a 10% tetracycline hydrochloride solution was applied to one tooth for 4 minutes (T group), followed by irrigation with saline. The contralateral tooth served as a control (C group). The flaps were repositioned and sutured. The animals were sacrificed at 6 months postoperatively and histological sections were processed. Computer-assisted histomorphometric analysis was used to evaluate the formation of new cementum, new bone, new connective tissue attachment, and length of the epithelium (junctional and sulcular).

RESULTS

Bone regeneration was similar in both groups (1.5 +/- 0.3 mm for the T group and 1.5 +/- 0.6 mm for the C group). The C group showed more new cementum than the T group (2.3 +/- 0.3 mm versus 2.2 +/- 0.3 mm) as well as a longer epithelium (1.0 +/- 0.3 mm versus 0.9 +/- 0.2 mm). The T group presented more new connective tissue attachment (3.1 +/- 0.2 mm) than the C group (2.9 +/- 0.6 mm). However, no statistically significant differences were detected between the two groups.

CONCLUSIONS

The amount of new attachment was similar in both groups. Root conditioning with 10% tetracycline solution did not produce any additional new attachment in comparison to the controls.

Mandibular bone deficit with a histologic study in man

The aim of this study was that to determine the clinical and histologic results of a new hydroxyapatite, with innovative properties compared with the other alloplastic materials used in the regenerative treatment of grade 3 bony defects of the mandibular furcations in the human. The hydroxyapatite used in our research is characterized by a scarce density and crystallinity, while from a microstructural point of view, the granules have nanometric dimensions (0.05-0.1 microm). The patient reported here by the authors had a grade 3 infrabony defect into a mandibular furcation. The surgical procedure used consists of the creation of a flap, roots planing, the conditioning of the roots with tetracycline HC, the accurate positioning of the granules of the hydroxyapatite in the furcation area, the crown replacing of the flap, and finally the suture of the same. Six months after the insertion of hydroxyapatite, the clinical effect was studied, comparing the variations found in probing the insertion of depth. At the end of the treatment, a block section of the molar was performed, with part of the surrounding soft tissues, whose histologic analysis underlined the moderate and initial formation of bony tissue, periodontal ligament, and radicular cement in the middle and lower portion of the furcation. In light of these results, the authors conclude that the use of this new hydroxyapatite is promising in the treatment of the mandibular furcations in the human, even if it will be necessary to continue to test its effectiveness through more studies.

Root resorption and ankylosis associated with guided tissue regeneration

BACKGROUND

Root resorption and ankylosis have been reported rarely as sequelae to guided tissue regeneration (GTR). The authors describe a clinical case of root resorption following GTR that involved the use of a bioabsorbable membrane.

CASE DESCRIPTION

Two years after GTR was performed on a Class II furcation defect, the clinical examination revealed root resorption reaching the pulp chamber. The furcation defect was filled with epithelium and connective tissue, which contained inflammatory infiltrate and fragments of the membrane. The authors also observed areas of the tooth that exhibited points of ankylosis and root resorption.

CLINICAL IMPLICATIONS

Clinical trials have reported favorable clinical and histologic results with GTR. However, this case report, along with other case reports and studies in animals, suggests a high risk of root resorption and ankylosis after GTR, which could limit the indications for this technique.

Effect of Locally Delivered Doxycycline Hyclate on Human Fibroblast Attachment to Subgingival Calculus

BACKGROUND

Clinical studies using locally applied doxycycline hyclate (DHV) have demonstrated significant probing depth reduction and gain in clinical attachment as a monotherapy without scaling and root planing. The mechanism for this attachment level gain to the non-root planed tooth is not understood. The purpose of this study was to investigate the effect of locally applied doxycycline hyclate on human gingival fibroblast attachment to subgingival calculus on contaminated root surfaces.

METHODS

Two separate experiments were performed, both on subgingival calculus. In experiment 1, teeth with subgingival calculus were treated with either doxcycycline hyclate in bioabsorbable vehicle (DHV) or with vehicle control (VC) in vivo. In experiment 2, teeth with subgingival calculus were treated with DHV, VC, scaling and root planing (SRP), or no treatment in vitro. The amount of cell attachment to calculus-covered root surfaces was quantitatively compared using a fluorescent dye assay and epifluorescence microscope. Values for cell attachment are presented as the mean standard deviation of the mean. The data were evaluated using Student t test.

RESULTS

In both experiments, there was no statistically significant difference in fibroblast attachment in the DHV, VC, or no treatment groups (P >0.05). The SRP group showed significantly more cellular attachment to tooth surfaces formerly covered by subgingival calculus than all other groups (P <0.001). In general, more cells attached to cementum than to calculus. Root chips that showed no attachment to the subgingival calculus also had no cells attached to the adjacent cemental root surface.

CONCLUSION

The addition of doxycycline hyclate in a bioabsorbable vehicle used as a locally delivered drug did not enhance the initial cellular attachment of human gingival fibroblasts to subgingival calculus or contaminated root surfaces.

Pulp revascularization of replanted immature dog teeth after treatment with minocycline and doxycycline assessed by laser Doppler flowmetry, radiography, and histology

This study investigated the effect of topical antibiotic treatment on pulp revascularization in replanted teeth. Thirty-four immature teeth were selected from three young dogs. Baseline radiographs and laser Doppler flowmetry (LDF) readings were obtained. Specimens were randomly divided into four groups: Thirty-eight teeth were extracted, kept dry for 5 min, and either (Group 1) covered with minocycline mixture (G1, n = 11), (Group 2) soaked in doxycycline (G2, n = 11), or (Group 3) soaked in saline (G3-negative control, n = 6), and replanted. Teeth in Group 4 were not extracted (positive control, n = 6). Postoperative radiographs and LDF readings were obtained for 2 months after replantation. After sacrifice, the jaws were collected and processed for light microscopy. Pre- and postreplantation LDF readings and radiographs, and histologic findings were analyzed to assess revascularization. Pulp revascularization occurred in 91% (G1), 73% (G2), and 33% (G3) of the specimens. In conclusion, minocycline facilitates pulp revascularization in replanted immature teeth after replantation.

Efficacy of Chemical Root Surface Modifiers in the Treatment of Periodontal Disease. A Systematic Review

BACKGROUND

Periodontal regeneration has been a relentless goal of the periodontist. Perhaps the oldest and most frequently attempted type of regeneration has involved chemical modification of the root surface. Varying results from histological and clinical studies have created controversy about the clinical effectiveness of root surface decalcification.

RATIONALE

This systematic review assesses the efficacy of root surface biomodification through the use of citric acid, tetracycline, or ethylenediaminetetraacetic acid (EDTA) in patients with chronic periodontitis.

FOCUSED QUESTION

Does the use of chemical root declacification result in effective periodontal regeneration and improved clinical outcomes in patients with chronic periodontitis?

SEARCH PROTOCOL

The Cochrane Database of Systematic Reviews; Database of Abstracts of Reviews of Effectiveness; Cochrane Central Register of Controlled Trials; American College of Physicians Journal Club, evidence-based MEDLINE journals; and National Center for Biotechnology Information PubMed Journals, as well as Dogpile, Google, and Copernic search engines were screened. Hand searches were performed on the Journal of Clinical Periodontology, Journal of Periodontology, Journal of Periodontal Research, and Periodontology 2000. Searches were performed for relevant clinical trials published through September 25, 2002.

SELECTION CRITERIA

INCLUSION CRITERIA

Histological and clinical studies evaluating the effects of citric acid, tetracycline, or EDTA on root surfaces of patients with chronic periodontitis were considered for inclusion.

EXCLUSION CRITERIA

Studies evaluating extracellular matrix proteins (e.g., fibronectin), enamel matrix proteins (e.g., amelogenins), or other proteins or growth factors applied to the root surface were not included.

DATA COLLECTION AND ANALYSIS

Primary outcome measures included changes in connective tissue attachment, cementogenesis, clinical attachment levels, probing depths, and gingival recession. Secondary outcome measures included changes in bone level, gingival inflammation, and plaque levels. Results for continuous outcome measures for primary variables (clinical attachment levels, probing depths, and recession) were expressed as mean differences or standardized mean differences. Clinical attachment levels and reduction in probing depth were evaluated using meta-analysis. All papers were rated according to methodological strength of evidence.

MAIN RESULTS

1. Thirty-four studies incorporating a total patient population of 575 were analyzed: 26 for citric acid, 5 for tetracycline, and 3 for EDTA treatment. 2. Four of 8 human histological studies reported regeneration with the use of citric acid. Only 1 of 18 clinical studies reported attachment gain. 3. Of the 5 studies examined using tetracycline, 1 histological study and 1 clinical study reported attachment gain. 4. No regeneration was reported in the 3 studies evaluating the use of EDTA. 5. Meta-analysis performed on 28 clinical trials did not show any significant effects of acid root treatment on attachment level gains or probing depth.

REVIEWER'S CONCLUSIONS

1. Evidence to date suggests that the use of citric acid, tetracycline, or EDTA to modify the root surface provides no benefit of clinical significance to regeneration in patients with chronic periodontitis. 2. The best method for ascertaining the clinical efficacy of acid-treated root regeneration would be to conduct a randomized clinical trial with sufficient statistical power that is supported by quantitative histological evaluation. 3. The majority of the studies that evaluated the regenerative potential of root surface modifiers were observational in nature; therefore, the value of conclusions reached in this manuscript must be carefully considered.

The putative collagen-binding peptide P-15 promotes fibroblast attachment to root shavings but not hydroxyapatite

BACKGROUND

Regenerative periodontal treatment aims to restore the attachment of the periodontal ligament and gingival collagen fibers to both the cementum of the root surface and alveolar bone. Fibroblasts are the predominant cells of the periodontal ligament and gingiva and have important roles in the function and regeneration of the tooth-supporting apparatus. This study investigated whether a putative collagen-based cell-binding peptide (P-15) increases gingival fibroblast attachment to root shavings and bone replacement graft (BRG) materials.

METHODS

Gingival and dermal fibroblast attachment to root shavings and BRG materials, and cell proliferation on root shavings and sections were measured fluorometrically. Root shavings and root sections obtained from periodontally healthy teeth were treated with P-15 at 2 concentrations (200 ng/g or 400 ng/g). Citric acid (CA)-treated root materials were also compared to untreated root shavings and root sections that served as negative control groups.

RESULTS

Attachment of all cells to bone fragments (whether freeze-dried or demineralized) was significantly greater than to hydroxyapatite (HA)-based BRG materials. The addition of P-15 to HA did not significantly increase gingival or dermal fibroblast attachment. At a concentration of 400 ng/g, P-15 significantly increased gingival and dermal fibroblast attachment to root shavings as compared to untreated shavings. Bone fragments, HA-based BRG materials, and untreated root shavings inhibited gingival fibroblast proliferation. Treatment of root sections with P-15 did not have any effect on gingival fibroblast proliferation.

CONCLUSIONS

P-15 is a potential alternative to CA for promoting fibroblast attachment to root surfaces. However, P-15 did not enhance fibroblast proliferation on root sections.

Effect of minocycline on healing of replanted dog teeth after extended dry times

Minocycline is available as a locally administered tetracycline derivative antibiotic (Arestin, OraPharma, Inc., Warminster, PA, USA) which demonstrated antibacterial activity and anti-inflammatory action that may slow down resorptive processes after severe traumatic injuries to the dentition. A total of 48 premolar roots of six mongrel dogs were instrumented in an aseptic fashion with rotary nickel-titanium files and obturated with vertically condensed warm gutta percha. All accesses were sealed with glass ionomer, the roots extracted and then allowed to bench dry for 60 min. Group 1 consisted of 15 roots that were coated with minocycline and replanted and nine roots that were replanted without minocycline. Group 2 consisted of 24 roots, all of which were prepared with a uniform cemental defect down to sound dentin along the lateral aspect of the root, with a high-speed bur following the 60-min dry time. Half of the roots (12) were then coated with minocycline and replanted, and the other 12 roots were replanted without minocycline. After 4 months, the dogs were killed and the roots prepared for histological evaluation. About 5- microm thick cross-sections of the root and surrounding tissue taken every 90 microm were evaluated for healing. In addition, residual root mass was also measured in the roots of group 1 to determine the extent of root structure loss for each treatment method. The roots with and without minocycline treatment showed no significant differences between the remaining root mass or the percentage of favorably healed root surfaces. The use of minocycline is not currently recommended for prevention or attenuation of external root resorption following avulsion in a dog trauma model.

The effect of topical minocycline on replacement resorption of replanted monkeys' teeth

Tetracycline has been reported to possess antiresorptive properties in addition to antimicrobial actions. Systemic administration of tetracycline showed variable results in the control of replacement resorption after replantation with good results in half of the cases, and almost no healing in the rest. The purpose of this study was to evaluate histologically the effect of topically applied minocycline on replacement resorption of replanted monkeys' teeth. Thirty-two roots from seven monkeys were endodontically treated aseptically to prevent inflammatory resorption of pulpal origin, a common sequela after avulsion injury. Teeth were then extracted as atraumatically as possible. Teeth in the negative control group (10 roots) were replanted almost immediately, while teeth in the positive control group (12 roots) were allowed to bench-dry for 1 h prior to replantation, both without further treatment. Teeth in the experimental group (10 roots) were bench-dried for 1 h, rinsed with saline, and then immersed in 1 ml of 50 mg ml(-1) minocycline hydrochloride for 5 min before replantation. No splinting was used. After 12 weeks, the animals were sacrificed and histological sections were prepared and evaluated according to a morphometric analysis modified from that described by Andreasen (1987) as complete healing, inflammatory resorption, and replacement resorption. Kruskal-Wallis test showed significant differences among the three groups in all the three healing categories. Further analysis with Mann-Whitney U-test showed teeth in the negative control group to have significantly higher complete healing and significant lower unfavorable healing, comprising of replacement resorption and inflammatory root resorption than the positive control group and the minocycline group. Topical application of minocycline to the root surface appeared to result in slightly higher occurrence of complete healing (32.46%) compared to the delayed replantation group with no minocycline treatment (positive control) (16.58%), but the difference was not statistically significant (P = 0.09).

Intentional replantation for periodontally involved hopeless teeth

The aim of this study was to evaluate the clinical and radiographic results of intentional replantation of periodontally involved teeth after conditioning of root surfaces with tetracycline-HCl. Thirteen patients (seven female, six male; age range: 35-52 years) with 15 periodontally involved hopeless teeth were included in this study. During the replantation procedure, the affected teeth were gently extracted, then the granulation tissues, calculus, remaining periodontal ligament and necrotic cementum on the root surfaces were removed. Tetracycline-HCl, at a concentration of 100 mg ml(-1), was applied for 5 min to the root surfaces. The teeth were then replaced into the socket and splinted. Patients were clinically and radiographically evaluated at baseline (time of surgery) and 6 months after the surgery. The following measurements were recorded: probing depth (PD), gingival recession (R), the amount of bone loss (BL) and bone gain (BG). Results indicated a reduction in PD and in the amount of bone loss and healthy gingiva. Mean PD was decreased from 5.25 to 2.36 mm, gingival recession was increased from 3.73 to 4.0 mm, and BL was reduced from 73.20 to 56.86%. At the end of 6 months, no root resorption or ankylosis was observed radiographically. Even during the short period of evaluation, it may be suggested that intentional replantation can be an alternative approach to extraction in cases where advanced periodontal destruction is present and no other treatments could be considered.

Long-term results of guided tissue regeneration therapy in the treatment of class II furcation defects: a randomized clinical trial

BACKGROUND

The purpose of this study was to evaluate the results after guided tissue regeneration (GTR) using a bioabsorbable membrane in Class II furcation defects in mandibular molars over a 24-month period.

METHODS

Nine patients with 2 comparable Class II furcation defects were included. The defects in each patient were randomly assigned to either test (GTR) or control (open flap debridement) group. Clinical measurements and standardized radiographs were taken at baseline, and at 6, 12, 18, and 24 months. The radiographs were analyzed by subtraction radiography.

RESULTS

There were significant probing depth reductions for both test and control groups (P < 0.007, P < 0.0005, respectively); however the differences between groups were not significant at any examination. The intra-group and inter-group differences in the vertical clinical attachment level gain were not significant (P > 0.05). Over 24 months, a significant horizontal clinical attachment level gain was observed in the test group compared to control (P<0.03). In the test group, 2 sites showed complete closure, one was converted to Class I, and one tooth was lost due to root resorption. In the control group, 2 defects progressed to Class III over 24 months. At 6 months, the test group showed 0.14 mm of bone loss while the control group showed 0.86 mm of bone gain (P = 0.035). The inter-group differences were not significant at 12, 18, and 24 months. A significant bone height gain was observed in the test group at 24 months when compared to the values obtained after 6 months (P = 0.015).

CONCLUSION

GTR may provide a greater horizontal clinical attachment level gain with the possibility of complete closure of some defects and stability over time.