Enamel matrix derivative and bone grafts for periodontal regeneration of intrabony defects. A systematic review and meta-analysis.

OBJECTIVE: The aim of the present systematic review and meta-analysis was to assess the clinical efficacy of regenerative periodontal surgery of intrabony defects using a combination of enamel matrix derivative (EMD) and bone graft compared with that of EMD alone. MATERIALS AND METHODS: The Cochrane Oral Health Group specialist trials, MEDLINE, and EMBASE databases were searched for entries up to February 2014. The primary outcome was gain of clinical attachment (CAL). Weighted means and forest plots were calculated for CAL gain, probing depth (PD), and gingival recession (REC). RESULTS: Twelve studies reporting on 434 patients and 548 intrabony defects were selected for the analysis. Mean CAL gain amounted to 3.76 ± 1.07 mm (median 3.63 95 % CI 3.51-3.75) following treatment with a combination of EMD and bone graft and to 3.32 ± 1.04 mm (median 3.40; 95 % CI 3.28-3.52) following treatment with EMD alone. Mean PD reduction measured 4.22 ± 1.20 mm (median 4.10; 95 % CI 3.96-4.24) at sites treated with EMD and bone graft and yielded 4.12 ± 1.07 mm (median 4.00; 95 % CI 3.88-4.12) at sites treated with EMD alone. Mean REC increase amounted to 0.76 ± 0.42 mm (median 0.63; 95 % CI 0.58-0.68) at sites treated with EMD and bone graft and to 0.91 ± 0.26 mm (median 0.90; 95 % CI 0.87-0.93) at sites treated with EMD alone. CONCLUSIONS: Within their limits, the present results indicate that the combination of EMD and bone grafts may result in additional clinical improvements in terms of CAL gain and PD reduction compared with those obtained with EMD alone. The potential influence of the chosen graft material or of the surgical procedure (i.e., flap design) on the clinical outcomes is unclear. CLINICAL RELEVANCE: The present findings support the use of EMD and bone grafts for the treatment of intrabony periodontal defects.

Anticoagulant therapy in patients undergoing dental interventions: a critical review of the literature and current perspectives.

Patients treated with oral anticoagulant therapy (OAT) represent an issue to the dentist, as an increasing number of people are using anticoagulant drugs for cardiovascular disease. The choice of an eventual suspension or continuation of anticoagulant therapy is important when considering an efficient management of the patient. Patients in anticoagulant therapy and requiring dental procedures sometimes represent therapeutic concerns especially concerning the suspension of the anticoagulant treatment. At the moment there is no consensus among international experts of a possible discontinuation of therapy before invasive dental procedures. In this paper, the authors try to focus on this topic through a critical review of the literature. Most of the studies suggest the continuation of the anticoagulant treatment with heparin before invasive oral surgical interventions. Based on the data of the literature, two rules must be adopted in clinical practice: 1) maintenance of anticoagulation related to the international normalized ratio (INR); 2) local application of antifibrinolytic agents to ensure a proper hemostatic process. Given the widespread use of anticoagulant drugs in cardiovascular disease, dentists must often face the problem of the therapy and, since there is no consensus on the management of these patients, the authors propose, after a thorough critical review of the literature, the implementation of a multiphase protocol of surgical approach to be implemented with safety in daily clinical practice.

Effects of titanium surface topography on morphology and in vitro activity of human gingival fibroblasts.

AIM: The aim of the present study was to evaluate in vitro the biological behavior of human gingival fibroblasts cultured on two different titanium surfaces. METHODS: Titanium test disks were prepared with a machined, relatively smooth (S) surface or a rough surface (O) obtained by a double acid etching procedure. Primary cultures of human gingival fibroblasts were plated on the experimental titanium disks and cultured up to 14 days. Titanium disk surfaces were analysed by scanning electron microscopy (SEM). Cell proliferation and a quantitative analysis by ELISA in situ of ECM components as CoI, FN and TN were performed. RESULTS: Results have shown different effects of titanium surface microtopography on cell expression and differentiation. At 96 hours of culture on experimental surfaces human gingival fibroblasts displayed a favourable cell attachment and proliferation on both surfaces although showing some differences. CONCLUSION: Both the relatively smooth and the etched surfaces interacted actively with in vitro cultures of human gingival fibroblasts, promoting cell proliferation and differentiation. Results suggested that the microtopography of a double acid-etched rough surface may induce a greater Co I and FN production, thus conditioning in vivo the biological behaviour of human gingival fibroblasts during the process of peri-implant soft tissue healing.

Dentinogenic ghost cell tumor: histopathology and clinical aspects in pediatric age.

The dentinogenic ghost cell tumor (DGCT) is a rare benign odontogenic tumor histologically characterized by islands of odontogenic epithelium with the presence of ghost cells and dysplastic dentin at different stages of calcification. Central DGCT may have a locally invasive behavior with variable rates of recurrence. We report the distinguishing case of two central DGCTs localized bilaterally in the maxilla of a female patient in pediatric age, initially detected as complex odontomas associated with impacted teeth and surgically removed by means of piezoelectric bone surgery. After the removal of odontogenic lesions with the presence of calcified tissues, histopathological examination allows the identification of lesions that, although uncommon, show the potential of local invasiveness requiring an adequate follow-up in order to observe any sign of disease recurrence.

In vitro expression of osteoblastic phenotype on titanium surfaces.

AIM: Differentiation toward the osteoblastic phenotype is a complex phenomenon regulated by means of several factors. Numerous studies in vitro et in vivo showed that surface properties of titanium dental implants modulate cell proliferation and osteoblastic differentiation, affecting bone healing processes. Optimal superficial morphology is still controversial. The aim of the present study was to evaluate in vitro the effects of two different titanium surfaces on biological behaviour of human osteoblast-like cells SaOS-2 with regard to production of extra-cellular matrix (ECM) proteins. METHODS: Human osteoblast-like cells SaOS-2, cultured on commercially pure titanium disks with two different surface topographies, smooth and microstructured with sand-blasting and acid-etching treatment, were evaluated by investigating adhesion, proliferation and deposition of extra-cellular matrix (ECM) proteins Fibronectin, Tenascin and Collagen I. RESULTS: The different values of cellular adhesion at three hours and the increase of SaOS-2 proliferation values at the different experimental times on both evaluated surfaces didn't result statistically significant. ECM deposition analysis showed that Fibronectin, Tenascin and Collagen I were gradually produced, with not statistically significant differences for Fibrone-ctin and Tenascin and statistically significant differences for Collagen I. CONCLUSION: Implant surface properties modulate in vitro the biological behavior of osteoblasts-like cells SaOS-2. SaOS-2 cells proliferate on both evaluated surfaces, showing a more organized differentiation towards an osteoblastic phenotype in ECM proteins production when cultured on microstructured surface.

Evaluation of the efficacy of celecoxib and ibuprofen on postoperative pain, swelling, and mouth opening after surgical removal of impacted third molars: a randomized, controlled clinical trial.

The objective of this study was to compare the efficacy of celecoxib and ibuprofen in reducing postoperative sequelae following the surgical removal of impacted mandibular third molars. Ninety-eight subjects who needed surgical extraction of an impacted mandibular third molar were selected for the study. All subjects were randomly allocated to receive one of the following treatments twice a day for 5days after surgery: placebo (n=32), ibuprofen (n=33), or celecoxib (n=33). The primary outcome chosen was postoperative pain, which was evaluated using the visual analogue scale (VAS) score recorded by each patient. The secondary outcomes chosen were changes in postoperative swelling and maximum mouth opening values compared to preoperative ones. Compared to placebo, treatment with celecoxib and ibuprofen resulted in improvements in the primary outcome. Furthermore, when compared to the other groups, patients in the celecoxib group showed a significant reduction in postoperative pain scores at 6h (P<0.001), 12h (P=0.011), and 24h (P=0.041) after surgery. Regarding swelling and maximum mouth opening values, there were no significant differences between the groups at each follow-up session. This study demonstrated that treatment with celecoxib decreased the incidence and severity of postoperative pain following third molar surgery compared to ibuprofen and placebo.

Peri-implant tissue healing in implant placed in post-extraction sockets of maxillary premolars.

AIM: The aim of this study was the clinical and radiographic evaluation of peri-implant tissues healing associated with two-stage implants performed with one-stage surgery and placed into post-extraction sockets of maxillary premolars. METHODS: Ten natural tapered submerged titanium implants with double acid-etched surface were installed in post-extraction sockets of maxillary premolars showing no bone dehiscence or fenestrations. Implants were selected according to the greatest dimension compatible to vertical and horizontal diameters of the post-extraction sockets. Peri-implant defects showing more than 2 mm of distance between the marginal palatal bone and the implant margin, were not treated with a regenerative procedure but with a bone swaging technique by means of piezoelectric surgery. At 16 weeks osteointegration of implants was examined with a clinical and standardized radiographic evaluation. RESULTS: All patients showed good clinical healing without any complication. At 16 weeks all implants, either those with reduced marginal defect or those with modified crestal bone profile, were osteointegrated. CONCLUSIONS: The use of two-stage implants performed with one-stage surgery in 4 walls post-extraction sockets of maxillary premolars, seems to allow osteointegration both in reduced peri-implant horizontal defects as well as in defects larger than 2 mm. Furthermore, these procedures seem to simplify the management of soft peri-implant tissues.

Conservative surgical management of patients with bisphosphonate-related osteonecrosis of the jaws: a series of 120 patients.

We evaluated retrospectively the efficacy of local resection for patients who presented with bisphosphonate-related osteonecrosis of the jaw (BRONJ). We studied 120 subjects with who required local resection of 129 BRONJ lesions that had not responded to medical treatment. The primary outcomes were improvement of the clinical stage of BRONJ and resolution of disease, and the secondary outcome was the influence of the surgeon's experience on the healing of the lesions. Age, sex, underlying diseases, smoking, and coexisting conditions were recorded. Logistic regression analysis was used to isolate factors that could potentially affect the outcome. Most of the lesions (n=107, 84%) improved postoperatively, 20 showed no change, and one got worse. One patient died. Stratification indicated complete healing and total resolution of disease for all 26 stage I lesions, improvement for 67 of the 77 stage II lesions, and for 14 of the 25 stage III lesions. The disease resolved in 67 of the 69 stage II lesions, and 14 of the stage III cases. Logistic regression indicated that smoking and the stage of disease could affect the outcome. Analysis of the surgeons' learning curve showed that performance improved significantly over time. Complete healing after local resection increased from 40% to 80% over a period of eight years (p<0.001). We conclude that local resection may be the treatment of choice in BRONJ stages I and II. Stage III might be better treated with either resection or clinical monitoring according to the condition of the patient.

Behavior of SaOS-2 cells cultured on different titanium surfaces.

Surface properties may affect the clinical outcome of titanium dental implants. The aim of the present study was to investigate the effects of 3 different titanium surfaces-smooth (S), sandblasted (SB), and titanium plasma-sprayed (TPS)-on proliferation, differentiation, and apoptosis of human osteoblast-like cells, SaOS-2. Cell proliferation was significantly (p < 0.05) higher on the S surface, and synthesis of extracellular matrix proteins was more abundant on TPS and SB than on S surfaces. Analysis of integrin receptors showed a higher expression of alpha2, alpha5, alphaVbeta3, and ss1 on TPS as compared with SB and S surfaces. An increase in alkaline phosphatase activity was detected only on SB and TPS surfaces. Analysis of cell apoptosis did not demonstrate any significant difference among the 3 different surfaces. The results indicate that titanium surface topography affects proliferation and differentiation of osteoblast-like SaOS-2 cells, suggesting that surface properties might be important for bone response around dental implants in vivo.

Generalized juvenile periodontitis: report of a familial case followed for 5 years.

The case of a family, followed for 5 years and showing an exceptionally high prevalence of Generalized Juvenile Periodontitis (GJP), is presented. Two siblings were affected by a severe form of GJP meanwhile the dycorial twin of one was periodontally healthy. Both the affected siblings showed infection by Actinobacillus actinomycetemcomitans (Aa), but only one presented a reduced chemotaxis of the peripheral PMNs. The dycorial twin consistently displayed a freedom from Aa and a reduction in the peripheral PMNs chemotaxis. The extraction of the compromised teeth in the two affected siblings has been followed by colonization of new sites by Aa; only repeated administration of systemic tetracyclines seems to protect the subjects from colonization of other sites. These findings may contribute to the understanding of the etiology, pathogenesis, and therapy of juvenile periodontitis.

Recolonization of the subgingival microflora after scaling and root planing in human periodontitis.

The purpose of this study was to evaluate the recolonization patterns of the subgingival microflora of adult periodontitis patients after a single session of scaling and root planing. In each of eight patients, three clinically diseased sites were investigated microbiologically by darkfield microscopy and cultural analysis. After initial clinical and microbiological parameters were determined, each subject received a single session of scaling and root planing but no oral hygiene instructions. Clinical indices were measured and microbial parameters were reassessed 7, 21, and 60 days after treatment in a manner such that each of the test sites was sampled only once after treatment. Recolonization was evaluated by matching any single site with its own preoperative site. A significant improvement in probing depth was noted for up to 60 days after treatment, while the gingival index did not change markedly during the course of the study. The microbial composition of treated sites 7 days after scaling and root planing, as determined by both cultural and darkfield data, was similar to that of periodontally healthy sites. Differences between cultural and darkfield data became apparent at the 21 day sampling point. The darkfield data showed that the sites consisted of cocci with few spirochetes. Cultural data demonstrated that the majority of the cocci were anaerobic, namely Streptococcus intermedius, Veillonella parvula, and Peptostreptococcus micros. At 60 days, there was no significant variation in any of the parameters from pretreatment levels. The most prevalent anaerobic rods prior to and 60 days after therapy were Fusobacterium nucleatum, Bacteroides gingivalis, and B. intermedius.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimicrobial susceptibility of periodontopathic bacteria associated with failing implants.

The aim of this study was to examine the subgingival microflora associated with failing implants, and to determine their susceptibility to commonly used antibiotics in periodontal therapy and dental practice. Thirteen partially edentulous patients with 19 failing implants were selected. Clinical examination included probing depth, attachment level, gingival index, plaque index, and radiographic analyses. Two subgingival plaque samples were taken from each failing implant and analyzed for microbial composition. Fusobacterium nucleatum, Porphyromonas gingivalis, and Prevotella intermedia were the prevalent cultivable microflora. Antimicrobial susceptibility of isolates was determined by the agar dilution technique. Antibacterial activity of penicillin G, amoxicillin, amoxicillin-clavulanate, and the combination amoxicillin-metronidazole was significantly higher than with other antibiotics tested. These data indicated that the commonly-used antibiotics were highly effective against bacteria isolated around failing implants, which would suggest the use of these antibiotics to control peri-implant infections.

Periodontal status and selected cultivable anaerobic microflora of insulin-dependent juvenile diabetics.

The periodontal status and subgingival microflora of insulin-dependent juvenile diabetic (JD) patients (n = 16, mean age = 11.3) were compared with that of their non-diabetic cohabiting healthy siblings (HS, n = 16, mean age = 13.2). JD patients were monitored every 3 months for levels of glycosylated hemoglobin (HbA1c) and clinical and microbial parameters were measured 6 weeks before drawing blood for levels of HbA1c (M% = 8.76). Clinical indices, measured for the entire permanent dentition, included: probing depth (PD), attachment level (AL), sulcus bleeding index (SBI), and plaque index (PI). Subgingival plaque samples were obtained at 2 sites from each subject; whenever possible, the site with the deepest probing depth and the mesial aspect of the maxillary right first molar were used. Microbial analyses were determined by cultural characteristics and biochemical tests. No significant differences were detected in any of the clinical indices for the entire dentition. The mean AL for JD sites was 2.32 +/- 0.83 mm and for HS sites was 2.2 +/- 0.85 mm. Mean percentage of total cultivable anaerobic microflora included Capnocytophaga spp. (JD, 13.21%; HS, 11%) and Porphyromonas gingivalis (JD, 5.1%; HS, 7.9%). Differences between the two groups were not statistically significant. When cluster analysis was performed on sampled sites, one cluster group in JD patients showed significantly elevated P. gingivalis and lower Capnocytophaga spp. levels as compared to the overall mean. The clinical parameters of this cluster were characterized by statistically significant greater loss of attachment and probing depth. These data would suggest few differences between JD patients and their HS in this population.

Periodontal status and subgingival microbiota of insulin-dependent juvenile diabetics: a 3-year longitudinal study.

This study examined for 3 years the changes in periodontal status and the possible correlations with selected subgingival microbiota and diabetic conditions in a group of 16 insulin-dependent diabetes mellitus (IDDM, JD) patients as compared with their 16 healthy cohabiting siblings (HS). JD patients were monitored every 3 months for levels of glycosylated hemoglobin (HbA1C). Clinical and microbiological parameters were measured 6 weeks before drawing blood to determine levels of HbA1C. Periodontal parameters were measured at baseline (TO), year 2 (T2), year 3 (T3) and included: probing depth (PD), attachment level (AL), sulcus bleeding index (SBI), and plaque index (PI). Two sites in each patient were selected for microbial samples: a mesio-facial aspect of the maxillary right first molar (defined as constant site, CS) and a site with the greatest probing depth (defined as deepest site, DS). Microbial samples were analyzed by culture techniques. No significant differences in clinical parameters were found between diabetics and healthy siblings at any examination. The SBI in the non-diabetic group at T2 and at T3 was significantly lower than at baseline. PD and AL of constant sites in the diabetic group at T3 were significantly higher than baseline. There was a significant increase in Prevotella intermedia at T3 as compared with baseline for deepest sites in the diabetic group. Cluster analysis revealed, in a former study, two clusters (IV and V) at baseline which were significantly different from the overall mean regarding composition of Porphyromonas gingivalis and Capnocytophaga spp. They were not significantly different for periodontal parameters from TO to T3. These data would suggest no significant differences in clinical parameters between the diabetics and non-diabetic siblings throughout this 3-year longitudinal study.

Longitudinal study of dental implants in a periodontally compromised population.

BACKGROUND: The purpose of this longitudinal study was to determine the clinical status and the composition of the subgingival microbiota of dental implants and natural teeth in patients with a history of periodontitis. METHODS: Twenty-five partially edentulous patients treated for moderate to advanced adult periodontitis and having a total of 42 implants participated in this 3-year study. The assessment of clinical status was done 1, 2, and 3 years after prosthetic loading (T1, T2, and T3, respectively). Clinical parameters evaluated included probing depth (PD), clinical attachment level (CAL), gingival index (GI), and plaque index (PI). The subgingival microbiota at peri-implant and periodontal sites were analyzed at T1 and T2. RESULTS: No significant difference in clinical parameters between implants and teeth and within the 2 groups between different time points was observed through the study. PD and CAL measurements of sampled periodontal and peri-implant sites did not show any statistically significant difference through the study and between the 2 groups. PI of sampled periodontal sites showed a statistically significant improvement during the study. From the morphological observation of the subgingival microbiota, a significant difference in the composition of motile rods between implants and teeth was found at T1. There were no differences detected in the subgingival microbiota, culturally identified at peri-implant and periodontal sites for the duration of the study. CONCLUSIONS: In conclusion, implants were colonized by the indigenous periodontal microbiota and were well maintained in patients with a history of periodontitis. No significant association between progressing or non-progressing periodontal or peri-implant sampled sites in terms of loss of attachment and infection with at least one of the searched periodontal pathogens was found, suggesting that the presence of putative periodontopathogens at peri-implant and periodontal sites may not be associated with future attachment loss or implant failure.

Different titanium surfaces modulate the bone phenotype of SaOS-2 osteoblast-like cells.

Commercially pure titanium implants presenting a relatively smooth, machined surface or a roughened endosseous surface show a large percentage of clinical success. Surface properties of dental implants seem to affect bone cells response. Implant topography appears to modulate cell growth and differentiation of osteoblasts affecting the bone healing around the titanium implant. The aim of the present study was to examine the effects of 1cm diameter and 1mm thick titanium disks on cellular morphology, adhesion and bone phenotypic expression of human osteoblast-like cells, SaOS-2. SaOS-2 cells were cultured on commercially 1 cm pure titanium disks with three different surface roughness: smooth (S), sandblasted (SB) and titanium plasma sprayed (TPS). Differences in the cellular morphology were found when they were grown on the three different surfaces. An uniform monolayer of cells recovered the S surface, while clusters of multilayered irregularly shaped cells were distributed on the rough SB and TPS surfaces. The adhesion of SaOS-2 cells, as measured after 3h of culture, was not affected by surface roughness. ECM components such as Collagen I (CoI), Fibronectin (FN), Vitronectin (VN) and Tenascin (TN) were secreted and organized only on the SB and TPS surfaces while they remained into the cytoplasm on the S surfaces. Osteopontin and BSP-II were largely detected on the SB and TPS surfaces, while only minimal production was observed on the S ones. These data show that titanium surface roughness affects bone differentiation of osteoblast like-cells, SaOS-2, indicating that surface properties may be able to modulate the osteoblast phenotype. These observations also suggest that the bone healing response around dental implants can be affected by surface topography.

[In vitro antibiotic sensitivity of several species of oral spirochetes]. / Antibiotico-sensibilità "in vitro" di alcune specie di spirochete orali.

Results of a series of "in vitro" antibiotic susceptibility tests on some strains of oral Treponema are presented. Different antimicrobial agents have shown different results and only tetracycline and erythromycin have shown consistent antibacterial properties. Surprisingly penicillin has allowed a latent "in vitro" growth of the tested Treponema. The Authors conclude that, according to the data presented, a revision of the current criteria of the antimicrobial therapy for the oral infections associated with the presence of species of Treponema is needed.

[The therapy of anterior disk dislocation in craniomandibular disorders. A clinical case report]. / Terapia del dislocamento anteriore del disco nei disordini craniomandibolari. Presentazione di un caso clinico.

The authors discuss the outcomes of therapy for CMDs and present a clinical case reporting an alternative method for the treatment of disc displacement. The orthopaedic therapy for CMDs is based on the use of interocclusal splints. Two kind of splints are prescribed to patients with CMDs: stabilization or repositioning splint. The former is used for a conservative treatment, the latter for irreversible treatment. In view of the poor long-term success of repositioning therapy, the cost of subsequent dental treatment, and the great potential for iatrogenic occlusal and muscular problems, the authors believe that the initial treatment approaches should be, in any case, conservative, reversible, and non invasive. The authors prescribe to their patients the repositioning splint for use either part-time or full time use. Part-time use is effective for preventing disc displacement without reduction. If used full time, once joint noises, pain, and displacement are decreased, the appliance should be adjusted to/or replaced with a stabilization appliance to allow posterior positioning of the mandible into a more physiologically stable position. The authors present a clinical case, a 27 yo female with disc displacement with reduction was treated with stabilization splint. After 6 weeks of therapy she returned reporting a temporary closed lock and sharp pain in the left TMJ. An anterior repositioning splint was fabricated in order to position the mandible forward. After 10 weeks of this treatment the patient reported absence of joint/muscle symptoms and of joint noise.(ABSTRACT TRUNCATED AT 250 WORDS)

[Implants in partially edentulous patients with history of periodontal disease]. / Impianti in pazienti parzialmente edentuli con storia di malattia parodontale.

BACKGROUND: Microbiota associated with periodontal diseases were also associated with periimplant diseases. The purpose of this study was to determine the clinical status and composition of subgingival microbiota of implants and natural teeth in a group of partially edentulous patients with history of periodontal disease. METHODS: 38 partially edentulous patients with history of periodontal disease, treated with dental implants, were selected for this study. Patients selected for the study were in good health condition and did not take any antibiotics in the last six months. One year after second stage surgery a total of 72 implants and 38 teeth underwent clinical and microbiological examination. Clinical parameters were PD, PAL, PI and GI. Subgingival plaque samples were analyzed by dark-field microscopy and cultural analysis. RESULTS: Clinical parameters didn't show any significant differences between periodontal and periimplant tissues. Dark-field microscopic examination showed higher prevalence of rods and spirochetes around implants than around teeth. There were no differences detected by cultural examination in the subgingival microbiota at peri-implant and periodontal sites. CONCLUSIONS: Findings from this study showed no differences between implants and teeth in partially edentulous patients with history of periodontal disease one year after second stage surgery. Implants were colonized by microbiota similar to that observed around teeth and were well-maintained in patients with a history of periodontitis.

Microbiotica associated with refractory periodontis. Prevalence and antibiotic susceptibility.

BACKGROUND: The aim of the present study was to analyze the composition of subgingival microflora in patients with refractory periodontitis and to evaluate the antimicrobial sensitivity of isolated periodontopathic microorganisms to different antibiotics. METHODS: Eleven subjects with a mean age of 46.4 years were selected for the present study. All had been treated for periodontal disease in the past. After further disease progression patients were included in this study. Eight subgingival plaque samples per patients were collected for cultural analysis. RESULTS: "Black pigmenting anaerobic bacilli" were the pathogenic microorganisms more frequently isolated. The findings from antibiotic susceptibility test showed that high number of bacteria associated with refractory periodontitis resulted resistant to erythromycin, metronidazole and tetracycline. The most effective antibiotics were ciprofloxacin, amoxicillin-metronidazole and amoxicillin-clavulanic acid. CONCLUSIONS: Microbiological analysis and antibiotic susceptibility test should be considered important tools in the management of patients with poor clinical response to conventional periodontal treatment.