Effects of Bifidobacterium animalis subsp. lactis HN019 on ligature-induced periodontitis in rats with experimental rheumatoid arthritis.

The purpose of this study was to evaluate the effects of systemic administration of the probiotic Bifidobacterium animalis subsp. lactis HN019 (HN019) on ligature-induced periodontitis in rats with experimental rheumatoid arthritis (RA). 28 rats were divided into four groups (n=7): RA (rheumatoid arthritis), RA/PROB (probiotic), RA/EP (experimental periodontitis) and RA/EP/PROB. From day zero, HN019 was added daily to the water of the PROB groups animals until the end of the experiment. From day seven, RA was induced. On day 28, in EP groups, ligatures were positioned around mandibular first molars and remained in position for 11 days, in order to induce periodontitis. The animals were euthanised on day 39. Microtomographic, histomorphometric, immunoenzymatic and microbiological analyses were performed. Data were statistically analysed (P<0.05). Group RA/EP/PROB presented reduced alveolar bone loss, tumour necrosis factor-α and interleukin (IL)-6 levels and increased IL-17 levels when compared with group RA/EP. There were no significant differences regarding connective tissue attachment level and IL-10 levels between groups RA/EP and RA/EP/PROB. Group RA/PROB showed decreased anti-citrullinated protein antibodies levels when compared with groups RA and RA/EP. Group RA/EP/PROB presented a higher rate of aerobic/anaerobic bacteria than group RA/EP. Systemic administration of HN019 promoted a protective effect against periodontal tissue destruction, decreasing both bone loss and inflammatory mediators and increasing the proportion of bacteria compatible with periodontal health, in rats with experimental RA and EP.

Rosuvastatin promotes benefits on induced periodontitis in hypertensive rats.

BACKGROUND AND OBJECTIVE: The potential benefits of statins in modulating periodontal disease is supported by in vitro and clinical studies showing statins can induce a lower expression of proinflammatory cytokines and matrix metalloproteinases. The aim of this study was to evaluate the effects of rosuvastatin (ST) on ligature-induced periodontitis in spontaneously hypertensive rats (SHR). MATERIAL AND METHODS: Fifty-four adult male rats were divided into three groups: SHR-C, SHR-L and SHR-L-ST (C, control; L, ligature groups). In the SHR-L-ST group, animals were treated with daily 2 mg/kg ST administration. In L groups, a ligature remained around mandibular first molars for 10 d. Each group was divided for killing at 10 or 21 d postoperatively. Microtomographic and histometric analyses were performed. Osteoclastogenesis was evaluated by tartrate-resistant acid phosphatase assay and gene expression of 84 proinflammatory mediators by polymerase chain reaction array. RESULTS: The SHR-L-ST group showed reduced bone loss and attachment loss in comparison with the SHR-L group at both 10 and 21 d postoperatively (p < 0.05). ST decreased the amount of tartrate-resistant acid phosphatase-positive cells compared with the SHR-L group at both 10 and 21 d (p < 0.05). The SHR-L-ST group presented 14 genes differentially expressed when compared with SHR-L group, featuring a downregulated gene profile at 10 d. CONCLUSION: Statin therapy may promote a protective effect against alveolar bone and connective tissue attachment losses attributable to periodontitis in hypertensive rats through inflammatory gene profile modulation.

Balancing the role of the dental school in teaching, research and patient care; including care for underserved areas.

Inequalities within dentistry are common and are reflected in wide differences in the levels of oral health and the standard of care available both within and between countries and communities. Furthermore there are patients, particularly those with special treatment needs, who do not have the same access to dental services as the general public. The dental school should aim to recruit students from varied backgrounds into all areas covered by the oral healthcare team and to train students to treat the full spectrum of patients including those with special needs. It is essential, however, that the dental student achieves a high standard of clinical competence and this cannot be gained by treating only those patients with low expectations for care. Balancing these aspects of clinical education is difficult. Research is an important stimulus to better teaching and better clinical care. It is recognized that dental school staff should be active in research, teaching, clinical work and frequently administration. Maintaining a balance between the commitments to clinical care, teaching and research while also taking account of underserved areas in each of these categories is a difficult challenge but one that has to be met to a high degree in a successful, modern dental school.

Teratogenic effects of the interaction acetylsalicylic acid (ASA) and ethanol: morphologic and morphometric evaluation of the lingual epithelium in rat fetuses.

The objective of the present work was to evaluate the teratogenic effects of the interaction between acetylsalicylic acid (ASA) and ethanol on the epithelium of the lingual mucosa in rat fetuses. On the 10th pregnancy day, a single intraperitoneal ethanol dose (2.96 g/kg body weight) (Group I), ASA (200 mg/kg body weight) (Group II) and ASA plus ethanol, in the same doses (Group III), or saline (Group IV - control), were administrated. The epithelial alterations were assessed by means of histological and morphometric methods, on posterior dorsal, anterior dorsal and ventral regions of the tongue. ASA reduced, in rat fetuses, the ethanol deleterious effects on nuclear size in the epithelial prickle cell of the lingual mucosa. On the other hand, ASA did not influence the effects of ethanol in both epithelial layers of the lingual mucosa, when the nuclear shape, cell volume or epithelial layers thickness were evaluated.

Osseointegration of oxidized and turned implants in circumferential bone defects with and without adjunctive therapies: an experimental study on BMP-2 and autogenous bone graft in the dog mandible.

The aim of the study was to compare the integration and implant stability of turned and oxidized titanium implants when placed in experimental bone defects with autogenous bone graft, BMP-2 or without adjunctive therapy. Four defects were prepared on each side of the mandible of 12 mongrel dogs five months after tooth extractions. Implants with turned and oxidized surfaces were placed in the defects. The circumferential gaps were filled with either autogenous bone grafts, a BMP-allogeneic dog mixture in a thermoplastic carrier, carrier alone or left without any treatment (control). There were no statistically significant differences between control and treated sites, neither for turned nor for oxidized implants with regard to histomorphometric measurements in ground sections and to implant stability as measured with resonance frequency analysis (RFA) after 4 and 12 weeks of healing. However, oxidized implants showed a significantly higher stability after 4 weeks and a tendency (p < 0.1) of that after 12 weeks. Histomorphometry showed more bone contacts for oxidized than for turned implants. It is concluded that oxidized implants gain stability more rapidly and integrate with more bone contacts than implants with a turned surface when placed in bone defects.

Multicenter study of hyaluronic acid obtained by biotechnology to evaluate clinical efficacy and safety in knee osteoarthritis.

Viscosuppplementation with intra-articular hyaluronic acid (hyaluronan [HA]) is a relatively new option for improving pain and articular function in patients with symptomatic knee osteoarthritis. An open multi-center study was performed in 365 patients with definite and symptomatic knee osteoarthritis from seven Latin American countries. Five doses of HA were administered once a week. The parameters studied were pain (six items), stiffness (two items) and functional capacity (17 items). The parameters were evaluated 1 week after the corresponding injection. Statistical differences were found when basal determinations of the three parameters were compared with the results of the first and fourth administration (p < 0.05). Intra-articular HA administration was well tolerated. Treatment-related nonserious adverse events were registered in 2.5% of administrations. Based on the results obtained, HA is a useful and well-tolerated symptomatic treatment for knee osteoarthritis with a rapid onset of action.

Modification of col shape and interproximal area after periodontal surgery associated with the restorative alveolar interface (RAI) technique. Histological study in dogs.

The modification of the col shape and position by the restorative alveolar interface technique (RAI) was studied in the interproximal areas between the mandibular first molars and fourth premolars of 10 dogs. Full thickness flaps were raised to expose the interproximal root surface and alveolar bone crest. The RAI procedure was performed only on the experimental sides and the control areas were the opposite side of the same animal. The animals were sacrificed at zero hour, 7, 14, 21 and 28 days for histological analyses. Approximately 6.0-micron-thick sections were made in buccolingual and mesiodistal directions and stained with hematoxylin-eosin and Mallory for light microscopy analysis. A satisfactory healing process was observed up to the 14th and 21st days which showed a modified col shape. At this time, an inflammatory reaction developed affecting the evolution of the healing. The surgery had probably created conditions for the installation of an inflammatory process resulting from the modified anatomy of the interdental area.

Preliminary evaluation of the hypoglycemic effect of some Brazilian medicinal plants.

The hypoglycemic effect of five Brazilian medicinal plants (Epidendrum monsenii, Marrubium vulgare, Rheedia gardneriana, Rubus imperialis and Wedelia paludosa) was studied on alloxan-induced diabetic rats. The extract of these plants was intragastrically administered to diabetic rats. The results showed that all plants studied (except R. gardneriana) significantly lowered the blood glucose. These results suggest that these four medicinal plants could be an adjuvant agent in the treatment of diabetes mellitus.

Acellular dermal matrix graft as a membrane for guided bone regeneration: a case report.

Guided bone regeneration has been successfully used to treat several types of bone defects. Problems associated with the procedure, such as premature exposure of the membranes to the oral cavity and, consequently, contamination, may occur. The acellular dermal matrix graft material is presently used to treat several soft tissue problems. It could be used for guided bone regeneration with the advantage of forming soft tissue while acting as a barrier membrane. A patient in need of guided bone regeneration for the staged placement of an implant was treated by using the acellular dermal matrix graft material as a barrier membrane. Healing progressed uneventfully with the formation of adequate new bone and an increase in the width of keratinized tissue.

Root trunk concavities as a risk factor for regenerative procedures of class II furcation lesions in dogs.

BACKGROUND: The purpose of this study was to evaluate the influence of root trunk concavities on guided tissue regeneration. METHODS: The second, third, and fourth mandibular bicuspids of 4 healthy mongrel dogs were used. Full flaps were elevated and furcation lesions (5 mm in height and 2 mm in depth) were surgically created. One mm deep concavities were prepared on the root trunks and part of the crown of all teeth. The second bicuspids remained as controls (C); the left third and fourth bicuspids received normal expanded polytetrafluoroethylene (ePTFE) membranes (NM) and the right bicuspids received modified ePTFE membranes (MM). The MM were made by removing the collar from an NM, cutting it into 2 mm segments, and suturing each of the segments to the collar of each MM. Normal and modified membranes were sutured to their corresponding teeth and the flaps sutured. After the healing period, the mandibles were removed and the teeth processed for histomorphometry. RESULTS: The results showed that the junctional epithelium measured a mean of 0.71 mm for C, 0.64 mm for NM, and 0.14 mm for MM. The differences between C and MM and between NM and MM were both statistically significant at the 5% level (Kruskal-Wallis test). Mean bone height measurements for the buccal surfaces from the furcation roofs were 2.79 mm for C, 2.60 mm for NM, and 1.06 mm for MM and for the mid-portion 1.10 mm for C, 1.23 mm for NM, and 0.30 mm for MM. Differences were statistically significant at the 1% level between C and MM and between NM and MM for the buccal measurements, and at the 5% level between NM and MM for the mid-portion measurements. CONCLUSIONS: Root trunk concavities are important risk factors for regenerative procedures. The collars of the membranes should be modified to improve results when concavities are present.

Management of soft tissue ridge deformities with acellular dermal matrix. Clinical approach and outcome after 6 months of treatment.

BACKGROUND: Soft tissue ridge defects often hamper ideally shaped artificial crowns and are basically treated using autogenous soft tissue grafts or alloplastic materials. These approaches present disadvantages such as the necessity of creating additional surgical fields to harvest the graft and the requirement of primary closure, which may reduce ridge height. This investigation evaluated the use of acellular dermal matrix (ADM) in the treatment of soft tissue ridge defects. METHODS: Eight patients, non-smokers with non-contributory medical history, provided 18 sites corresponding to missing teeth in the anterior maxillary arch. The ideal horizontal gain (desired gain) was waxed up in study casts, which served as templates for construction of modified acrylic stents with orthodontic wires. These stents served as references for ideal horizontal gain and also as fixed reference points for further evaluation. The distance from the orthodontic wire to the buccal plate of the defect also represented its baseline horizontal component. Vertical variations were evaluated with another stent and, in this case, no desired gain was considered. After raising partial-thickness flaps, the ADM material was rehydrated and folded to fill the defect and reproduce the desired gain. Flaps were sutured with no tension, and part of the material was intentionally left exposed to avoid pressure on the incision line and prevent height loss. Patients used local and systemic antimicrobials, and the sutures were removed at 7 days. RESULTS: Evaluations were carried out at 30 days, and 3 and 6 months, and all sites healed uneventfully. Neither infection nor significant pain was reported by the patients, and the material was covered by tissue at about 21 days. Mean horizontal gain of 1.72 +/- 0.59 mm (58.5%) at 6 months and mean shrinkage of 1.22 +/- 0.46 mm (41.4%) were observed. There was a mean improvement in vertical gain of only 0.61 +/- 0. 77 mm, although 66. 7% of the treated sites showed a 1 to 2 mm gain. Clinically, the total gain in the subjects was very effective and matched the receptor tissues nicely. CONCLUSIONS: ADM may be a suitable material for the treatment of soft tissue ridge deformities due to its biocompatibility, color matching, and horizontal gain. Additional controlled, comparative trials are necessary to establish its advantages and potential compared to autogenous soft tissue techniques.

Compliance with supportive periodontal therapy. Part II: Risk of non-compliance in a 10-year period.

Supportive periodontal therapy (SPT) is needed for the success of periodontal therapy; however, patient compliance is poor. Part II of this study analyzes compliance during a 10-year period in an attempt to identify the profile of patients with a higher risk of becoming non-compliant. Data from the records of 874 patients from a private periodontal clinic who had completed active periodontal treatment up to 10 years before and had begun supportive periodontal therapy were analyzed for risk of non-compliance and compliance. The factors evaluated were gender (326 males and 548 females), type of therapy (surgical or non-surgical) and age (< or = 30 years, 31 to 40, 41 to 50, and > or = 51 years old) and the association amongst them. In the period studied, compliance with SPT was 45.8%. Forty-three percent of males and 47% of females discontinued SPT. In the surgical group 43.9% were non-compliant and in the non-surgical group 53.2% were non-compliant. Fifty-nine percent of the patients < or = 30 years of age were also non-compliant. Female patients < or = 30 years and > or = 51 years of age that underwent non-surgical therapy were found to be of higher risk for non-compliance in the 10-year period studied.

Preprosthetic periodontal surgery in the interproximal area with modification of the COL area: anatomic and histologic study in dogs.

BACKGROUND: Due to its concave morphology, a COL creates difficulties for proper oral hygiene. When this characteristic is accentuated by tooth position or caries and when restorations are necessary, they should be corrected by preprosthetic surgery. However, there are no data proving the efficacy of the procedures. The purpose of this study was to evaluate tissue response to preprosthetic surgery to modify COL morphology. METHODS: Five mongrel dogs received apically positioned flaps, osteotomy/plasty, and RAI (restorative alveolar interface technique) on the maxillary right third bicuspid and first molar; on the same teeth on the left side, a large tissue excision similar to gingivectomy and RAI were performed. Histologic specimens stained with hematoxylin and eosin and Mallory were evaluated at hour 0 and 1, 2, 3, and 4 weeks under light microscopy. RESULTS: At hour 0, hemorrhage in the remaining interproximal tissue on the left side, and denuded bone modified by the osteotomy on the right side, were observed. At 1 week, both sides showed the presence of granulation tissue and the beginning of reepithelialization and fiber formation. At 2 weeks, the papillae were rebuilt and epithelialized, with fewer inflammatory cells and dilated blood vessels, with a convex morphology. At 3 weeks, the papillae were convex and saddle shaped, with thicker epithelium and denser connective tissue. The general aspect was similar to attached gingiva. However, on the right side, the total extension of the interproximal tissues was longer and had a less accentuated convex curvature. At 4 weeks, the tissues were more mature, but the morphologic and histological findings were similar to 3 weeks. CONCLUSION: Both techniques modified the COL morphology, suggesting that the RAI technique was effective; but the apically positioned flap with osteotomy and RAI created a more extensive convex surface and more interproximal space for the prosthesis. It is recommended that this technique be considered for use in humans.

Comparative 6-month clinical study of a subepithelial connective tissue graft and acellular dermal matrix graft for the treatment of gingival recession.

BACKGROUND: Different techniques have been proposed for the treatment of gingival recessions. This study compared the clinical results of gingival recession treatment using a subepithelial connective tissue graft and an acellular dermal matrix allograft. METHODS: Nine patients with bilateral Miller Class I or II gingival recessions were selected. A total of 30 recessions were treated and randomly assigned to the test group and the contralateral recession to the control group. In the control group, the exposed root surfaces were treated by the placement of a connective tissue graft in combination with a coronally positioned flap; in the test group, an acellular dermal matrix allograft was used as a substitute for palatal donor tissue. Probing depth, clinical attachment level, gingival recession, and width of keratinized tissue were measured 2 weeks prior to surgery and 3 and 6 months postsurgery. RESULTS: There were no statistically significant differences between the test group and the control group in terms of recession reduction, clinical attachment gain, and reduction in probing depth. The control group had a statistically significant increased area of keratinized tissue after 3 months compared to the test group. Both procedures, however, produced an increase in keratinized tissue after 6 months, with no statistically significant difference. CONCLUSION: The acellular dermal matrix allograft may be a substitute for palatal donor tissue in root coverage procedures.

Guided tissue regeneration associated with bovine-derived anorganic bone in mandibular class II furcation defects. 6-month results at re-entry.

BACKGROUND: The use of graft materials with guided tissue regeneration (GTR) in Class II furcation defects is aimed at improving the outcome of the regenerative technique. In this regard, however, there are a limited number of studies discussing the results obtained when GTR and graft materials are used in the treatment of Class II furcation defects. Furthermore, most studies employ either allogeneic or autogenous materials. The present trial sought to determine whether the use of a bovine-derived anorganic bone (ABB) in conjunction with GTR influenced the outcome of mandibular Class II furcation treatment. METHODS: This study included 14 patients who provided 15 pairs of similar periodontal defects. Each defect was randomly assigned to treatment with either a cellulose membrane in combination with bovine-derived anorganic bone (GTR+ABB) or membrane alone (GTR). Following basic therapy, baseline measurements were recorded including probing depth (PD), clinical attachment level (CAL), and gingival margin position (GMP). Hard tissue measurements were performed during surgery to determine alveolar crestal height (CEJ-AC), and vertical (VDD) and horizontal defect depth (HDD). Membranes remained in position for at least 4 weeks. After 6 months, all sites were re-entered and soft and hard tissue measurements were recorded. RESULTS: Both surgical procedures resulted in statistically significant probing depth reduction and gain in clinical attachment levels, with no significant difference between groups. Gingival recession was more pronounced in the GTR+ABB group (0.87 +/- 0.83 mm), but not statistically different from the GTR group (0.46 +/- 1.19 mm). Vertical defect resolution was significant in both groups (GTR: 1.60 +/- 1.50 mm; GTR+ABB: 1.80 +/- 2.11 mm), without differences between groups. Only horizontal furcation resolution (GTR: 2.47 +/- 0.99 mm; GTR+ABB: 3.27 +/- 1.39 mm) was significantly different between groups (P <0.05). CONCLUSIONS: The use of ABB with GTR techniques improved horizontal defect resolution in mandibular Class II furcation defects, but did not yield superior results regarding soft tissue changes when compared to sites treated with GTR alone. Evaluation of a larger sample could indicate differences and advantages between the evaluated approaches and confirm the real necessity of associating filling materials with GTR.

Use of bovine-derived anorganic bone associated with guided tissue regeneration in intrabony defects. Six-month evaluation at re-entry.

BACKGROUND: Different filling materials have been associated with guided tissue regeneration (GTR) in order to improve its regenerative potential and predictability. Anorganic bovine bone (ABB) has demonstrated biocompatibility and osteoconductive properties; however, there are limited data regarding its performance in the treatment of intrabony defects. This investigation aimed to evaluate the clinical outcome of the association of anorganic bovine bone with cellulose membranes in intrabony defects after 6 months. METHODS: Twenty-six paired intrabony defects were selected from 11 non-smoking patients with no relevant medical history. The defects were similar regarding the number of bony walls and defect depth, and presented pocket depths > or = 6 mm. Four weeks after completion of basic therapy, probing depth (PD), clinical attachment level (CAL), and gingival margin position (GP) were recorded (baseline values). The defects were then surgically accessed and debrided, and the intrabony component measured to the nearest millimeter with periodontal probes and customized acrylic stents (distance from the stent to the base of the defect and from the stent to the alveolar crest). Each intrabony defect was randomly assigned to receive the membrane alone (control, C) or the membrane with anorganic bovine bone (test, T). The patients were re-evaluated after 6 months, and re-entry procedures were performed. RESULTS: Significant (P <0.01) improvement in all variables was observed: mean pocket reduction of 4.61+/-1.60 mm (C) and 4.46+/-1.50 mm (T) and clinical attachment gain of 2.85+/-1.46 mm (C) and 3.15+/-1.40 mm (T); the difference between groups was not significant (P >0.05). Nevertheless, gingival recession in the control group (1.84+/-0.89 mm) was significantly (P <0.05) more pronounced than that observed in the test group (1.30+/-0.48 mm). Bone measurements indicated a significant resolution of the defects (P <0.01). A mean defect resolution of 2.76+/-0.72 mm (C) and 2.69+/-1.03 mm (T) and crestal resorption of 1.07+/-0.64 mm (C) and 1.30+/-0.85 mm (T) were detected (P >0.05). Stepwise multiple regression analysis indicated that for both groups, the baseline depth of the defects and the alveolar crest resorption accounted for 82% of the variability of bone fill observed in the control group (F = 23.65, P <0.001) and 89% in the test group (F = 41.32, P <0.001). CONCLUSIONS: ABB may be used in conjunction with GTR in the treatment of intrabony defects. Its use, however, did not result in a better outcome than the use of membranes alone. Studies employing more patients would be of interest in order to determine the advantages and indications of the tested approaches on a more predictable basis.

Necrotizing ulcerative periodontitis associated with severe congenital immunodeficiency in a prepubescent subject: clinical findings and response to intravenous immunoglobulin treatment.

Common variable immunodeficiency (CVID) is a rare multifactorial congenital disease of genetic origin caused by an impairment in the secretion of specific immunoglobulins. It manifests systemically through recurrent respiratory infections, gastrointestinal disorders and autoimmune diseases. Oral manifestations may include gingivitis and lichenoid lesions with Wickham's striae. The treatment for CVID is supported by using intravenous infusion of immunoglobulins (IVIG) that allows for control of the disease and avoidance of recurrent opportunistic infections. This report presents a case of necrotizing ulcerative periodontitis (NUP) in a young patient with CVID, and correlates his periodontal status with systemic conditions before and after IVIG administration during 1 year of evaluation.

Compliance with supportive periodontal therapy. Part 1. Risk of non-compliance in the first 5-year period.

BACKGROUND: Supportive periodontal therapy (SPT) is needed for the success of periodontal therapy; however, patient compliance is poor. This study evaluates records from non-compliant patients in an attempt to identify a profile of patients with a higher risk of becoming non-compliant. METHODS: Data on 874 patients who had completed active periodontal treatment up to 5 years earlier and who had begun SPT were analyzed for risk of non-compliance. The factors evaluated were gender (326 males and 548 females); type of therapy (surgical or non-surgical) and age (< or =20; 21 to 30; 31 to 40; 41 to 50; and > or =51 years) and the relationships among them. RESULTS: The overall rate of non-compliance was 46.8%, and the relative risk for non-compliance was greater in the younger age groups (< or =40 years old) when compared to the older groups. Gender, age, and type of therapy as independent factors were not significant risk factors for non-compliance, but the association of the 3 factors produced interesting results. CONCLUSIONS: This study suggests that certain patient groups have a higher risk of non-compliance and that clinicians should intensify their efforts in motivating and instructing these patient groups in the importance of SPT.

Supportive periodontal therapy in South America. A retrospective multi-practice study on compliance.

BACKGROUND: Supportive periodontal therapy is needed for the success of periodontal therapy but there is little information about the extent of patient cooperation. It is known, however, that cooperation is poor and a matter of concern. METHODS: The present study is part of a more extensive study including information from 5,041 patient records from private periodontal practices in Brazil, Venezuela, Chile, and Argentina. Patient cooperation was measured according to gender, age, type of therapy (surgical or non-surgical), maintenance period (first year, 5 years, 10 years, 15 years, and 20 years), and level of cooperation (non-compliant, regular or irregular) for each of the 4 practices. RESULTS: We observed a great variation in the behavior of the patients from different practices, suggesting that studies on compliance cannot be generalized because differences in culture, economic conditions, knowledge of oral hygiene, and even the philosophy of treatment should be considered. The most significant data were sometimes similar for 2 or 3 of the countries but never for all 4 practices. CONCLUSIONS: Compliance is a very complex matter and findings from individual studies cannot be generalized.

Immediate implants placed into infected sites: a histomorphometric study in dogs.

The study the effect of chronically infected sites on the immediate placement of implants, periapical lesions were induced in the third and fourth premolars of four dogs and the contralateral teeth were used as controls. Nine months after the induction of periapical lesions, experimental and control teeth were extracted, and 28 IMZ implants were immediately placed. After a healing period of 12 weeks, the animals were sacrificed, the hemimandibles were removed, and specimens were prepared to be hard-sectioned and stained with toluidine blue. All areas healed without inflammation or exudation and all implants were clinically immobile and were radiographically determined to be surrounded by normal-appearing bone. Histologically, there were no signs of infection, and the histomorphometric analyses revealed that 28.6% and 38.7% had osseointegrated for the experimental and control implants, respectively. The difference was not statistically significant. It was concluded that chronically infected sites, such as those showing signs of periapical pathosis, may not be a contraindication for immediate implants, if certain clinical measures and preoperative and postoperative care are taken.