Bond strength evaluation of three self-adhesive luting systems used for cementing composite and porcelain.

Self-adhesive resin cements were recently introduced with the purpose of simplifying the cementation technique, as they combine the use of adhesive and cement in a single application, eliminating the need for pretreatment of the tooth. In the present study a microtensile bond strength test (µ-TBS) was used to compare three self-adhesives, an etch-and-rinse and a self-etch luting system, in the cementation of resin-based composite (RBC) and ceramic disks to dentin. Freshly extracted molars were transversally sectioned to expose flat, deep dentin surfaces. Cylindrical specimens (5 mm in diameter and 10 mm in height), consisting of RBC disks and leucite-based glass ceramic disks, were produced. The RBC disks were sandblasted with 50-µm Al2O3. The ceramic disks were conditioned with 9.5% hydrofluoric acid gel and silane application. All of the disks were then bonded to dentin surfaces employing five different luting agents: iCEM Self Adhesive (Heraeus Kulzer), MaxCem (Kerr Corporation), RelyX UniCem (3M ESPE), EnaCem HF (Micerium), and Panavia F2.0 (Kuraray-Dental). The products were applied according to the manufacturers' instructions. The specimens were sectioned perpendicular to the adhesive interface to produce multiple beams measuring approximately 1 mm2 in cross section. For each experimental group 12 beams were tested. The preterm failures were also taken into account. All of the specimen preparations were performed by the same operator. The beams were tested under tension at a crosshead speed of 0.5 mm/min until failure. Mean µ-TBS values were calculated for each group. Data were analyzed by a two-way analysis of variance, and multiple comparisons were performed using a Tukey test (α=0.05). The UniCem group showed the lowest number of preterm failures among the tested self-adhesive systems. When premature debondings were included in the mean value calculation, bond strength values for the UniCem group were statistically equal to or even higher than those achieved with the other self-adhesives, although these values were still statistically worse than those obtained using traditional multi-step luting agents.

Clodronate combined with a surfactant (Tween 20) does not improve osseointegration: a rabbit immunohistomorphometric study.

Biphosphonates are compounds that inhibit bone reabsorption mediated by osteoclasts or the progression of periodontal disease independent on the host response to pathogenic bacteria that colonize the tooth surface. The use of biphosphonates in oral implantology is still in the experimental stage. The aim of this study is to evaluate the efficacy of a non-aminobiphosphonate combined with a surfactant to increase the ability of the drug to link to the implant and bone surfaces in the development of osseointegration in rabbits. Smooth titanium implants were devised to be used on rabbit femurs. A topical administration of clodronate combined with the surfactant (Tween 20) at different concentrations was made on the implant surface and in the implant site to increase the bone and implant adhesiveness. Placebo was given to the control group. New Zealand rabbits were used and sacrificed by CO2 after 8 weeks from the implantations. A histologic and histomorphometric analysis was carried out. Results did not show significant difference between the tests and the placebo groups. Our data are different from other similar studies obtaining statistically significant differences. These differences could depend on the efficacy of the drug used and on the procedure of application of the drug on the implant. This study demonstrates poor efficacy of clodronate applied topically to the implant and implant site during surgery to increase the percentage of osseointegration in the implant. Further studies using different fixation techniques of the drug may be necessary to confirm the present data.

Microbiological and biochemical effectiveness of an antiseptic gel on the bacterial contamination of the inner space of dental implants: a 3-month human longitudinal study.

Microbial penetration inside the implants internal cavity produces a bacterial reservoir that is associated with an area of inflamed connective tissue facing the fixture-abutment junction. The aim of this clinical trial is to evaluate the effectiveness of a 1 percent chlorhexidine gel on the internal bacterial contamination of implants with screw-retained abutments and on the level of AST secreted in peri-implant crevicular fluid. Twenty-five patients (aged 29 to 58 years) each received one implant. Three months after the end of the restorative treatment, and immediately after a clinical and radiographic examination and the abutment removal, microbiological samples were obtained from the internal part of each fixture and biochemical samples were collected by peri-implant sulci. The patients were then divided into two groups: the control (CG; n=10) and test (TG; n=15) groups. The CG had the abutment screwed into place and the crown cemented without any further intervention. In contrast, before the abutment placement and screw tightening, the TG had the internal part of the fixture filled with a 1 percent chlorhexidine gel. Three months later, the same clinical, microbiological and biochemical procedures were repeated in both groups. Total bacterial count, specific pathogens and AST activity were detected. The clinical parameters remained stable throughout the study. From baseline to the 3-month examination, the total bacterial counts underwent a significant reduction only in the TG. In contrast, the AST activity showed a significant increase in the CG. The administration of a 1% chlorhexidine gel appears to be an effective method for the reduction of bacterial colonization of the implant cavity and for safeguarding the health status of peri-implant tissue over a 3-month administration period.

Bevacizumab-related osteneocrosis of the jaw.

We describe a case of jaw bone necrosis after a lung adenocarcinoma bone metastasis, treated the first time in 2004 by means of pneumonectomy and lymph node ablation. One week after a dental extraction, the patient experienced pain in the mandibular region, in conjunction with alveolar bone exposure. Treatment with amoxicillin and clavulanate every 12 hours for 15 days and 0.2% chlorhexidine rinses was administered and there was a remission of infective complications, but not the closure of the exposed alveolar bone. Only at this time did the patient refer that he was treated with bevacizumab therapy immediately after the extraction. A preventive dental assessment of patients scheduled for bevacizumab therapy should be useful as for the zoledronic acid therapy. Dental surgery procedures for patients during bevacizumab therapy should be carefully evaluated and considered as the last choice, to reduce all possible risks and prevent complications.

Effect of a subgingival chlorhexidine chip on the clinical parameters and the levels of alkaline phosphatase activity in gingival crevicular fluid during the non-surgical treatment of periodontitis.

The main therapeutic approaches for inflammatory periodontal diseases include the mechanical treatment of root surfaces. Multi-center clinical trials have demonstrated that the adjunctive use of a chlorhexidine (CHX) chip is effective in improving clinical results compared to scaling and root planing (SRP) alone. However, some recent studies failed to confirm these clinical results, nor have any data been reported regarding the capability of the CHX chip in affecting the activity of alkaline phosphatase (ALP) in the gingival crevicular fluid (GCF). This enzyme has been related to a condition of destructive activity of periodontitis. The aim of this study is to provide further data on the clinical and biochemical effects of CHX chips when used as an adjunct to SRP. Eighty-two systemically healthy patients, aged 31-63, with moderate and advanced periodontitis were recruited from the departments of Periodontology of the University of Chieti. In each patient 2 experimental sites, located in two symmetric quadrants, were chosen with a probing depth of > or = 5 mm and bleeding on probing. The 2 sites were selected randomly at the split-mouth level; control sites received SRP alone, and test sites SRP plus 1 CHX chip. Clinical indices, including probing depth (PPD), clinical attachment level (CAL), bleeding on probing (BOP), and the ALP activity in GCF were evaluated at baseline and after 6 months. Alkaline phosphatase activity was assayed spectrophotometrically. The PPD and CAL were significantly lower at 6 months as compared to the baseline scores in both treatments (p less than 0.01). The PPD reduction was 2.7 mm in the CHX+SRP group and 1.9 mm in the SRP alone group. The CHX+SRP group showed a significantly greater gain of clinical attachment (mean: 1.4 mm) in comparison with the SRP group (mean: 0.9; p less than 0.05). No differences were observed in the decrease of the percent of BOP-positive sites between the experimental groups. Conversely, the CHX+SRP group underwent a significantly greater decrease (p less than 0.01) of the GCF-ALP activity 6 months after treatment in comparison with the SRP alone group. The adjunctive use of the CHX chip resulted in a significant improvement of pocket reduction and clinical attachment gain as compared with SRP alone. These results were concomitant with a significantly greater reduction of the GCF-ALP activity levels.

Sinus augmentation procedure of the jaw sinus in patients with mucocele.

The sinus augmentation procedure of the jaw sinus (SAP) is a surgical technique which permits the prosthetic rehabilitation of the edentulous saddles by the insertion of dental implants where unfavourable conditions exist for their application. Nevertheless, apart from malignant tumors, benign pathologies exist, such as mucocele or radicular cysts, which can complicate the SAP, causing sinusal disturbances. In this study we describe our experience of SAP in patients with mucocele of the jaw sinus, and describe our surgical technique without the preventive emptying of the mucocele. Based on our experience, the SAP operation can be carried out without complications if the distance between the top of the mucocele with SAP and the osteomeatal complex (OMC) is 22 mm, or for mucocele no larger than 18 mm. In fact, these parameters guarantee that, because of the lifting of the sinusal membrane, the antral drainage (AD) duct does not alter or become obstructed.

Biological considerations on the use of zirconia for dental devices.

Zirconium oxide, known as zirconia, is a ceramic material with optimal esthetical and mechanical properties. Zirconia stabilized with yttrium oxide has the best properties for medical uses. A stress on ZrO2 surface creates a crystalline modification that opposes to propagation of cracks. Zirconia core for fixed partial dentures (FPD) on anterior and posterior teeth and on implants are now available. Clinical evaluations after 3 years report good percentage of success for zirconia fixed partial denture. Zirconia biocompatibility was studied in vivo and in vitro by orthopedic research; no adverse responses were reported on insertion of ZrO2 samples in bone or muscle. In vitro experimentation showed absence of mutation and a good viability of cells cultured on this material.

SEM analysis of oral lichen planus before and after treatment with 13 cis-retinoic acid.

Cancer of the oral cavity is a frequent worldwide neoplasia, averaging 4% in men and 2% in women. Cancer of the oral cavity is often preceded by particular epithelial lesions, called precancerous lesions. The aim of this study is to evaluate, by SEM microscope analysis, before and after treatment with 0.1% 13-cis-retinoic, the morphostructural variation of the surface of the oral mucous affected by lichen planus in respect to healthy oral mucous. Following topical therapy with 0.1% 13-cis-retinoic acid for 8 weeks, a restoration of the physiological morphostructure was observed by SEM, demonstrating the efficaciousness of the treatment and the SEM analysis for identifying the lesions of oral epithelium.

Periodontal healing in humans using anorganic bovine bone and bovine peritoneum-derived collagen membrane: a clinical and histologic case report.

The authors report the clinical and histologic data on the healing of a severe periodontal lesion obtained in a one-walled intrabony defect using anorganic bovine bone under a bovine peritoneum-derived collagen membrane. Eight months after surgery, a bone-like tissue replaced the lost tissues. A biopsy of this tissue was carried out. In the part of the specimen closer to the residual bony wall of the original defect, anorganic bone particles (ABP) appeared to be surrounded by a layer of newly formed bone; its osteocyte lacunae were colonized by osteocytes from the host, and actively secreting osteoblasts were observed in many microscopic fields. No resorption phenomena were observed in the ABP Newly formed cementum with actively secreting cementoblasts was present on the tooth surface, and well-oriented fibers inserting in both newly formed cementum and bone were observed. In an area far from residual bone, all ABP did not appear to be surrounded by newly formed bone. Osteocytic lacunae appeared not to be colonized by cells, and ABP was surrounded by dense connective tissue without osteoblasts near the grafted particles. A very limited amount of newly formed bone, without relations with ABP, was observed close to the root surface. From a clinical point of view, anorganic bone in association with a collagen membrane can be effective in the treatment of bony defects characterized by an unfavorable architecture. From a histologic point of view, the clinical appearance of bone regeneration is not always confirmed in the part of the defect far from the bony walls.

Fluids and microbial penetration in the internal part of cement-retained versus screw-retained implant-abutment connections.

BACKGROUND: It has been recently observed that in implants with screw-retained abutments, in in vitro as well as in vivo conditions, bacteria can penetrate inside the internal cavity of the implant as a consequence of leakage at the implant-abutment interface. An alternative to screw-retained abutments is represented by implants that can receive cemented abutments. In this case, the abutment goes through a transmucosal friction implant extension (collar) and is cemented inside the internal hexagonal portion of the implant. The aim of the present research was to compare fluids and bacterial penetration in 2 different implant systems, one with cement-retained abutments (CRA) and the other with screw-retained abutments (SRA). METHODS: Twelve CRA dental implants and 12 SRA implants were used in this study. The research was done in 3 steps: scanning electron microscopic (SEM) analysis, fluid penetration analysis, and bacterial penetration analysis. RESULTS: 1) Under SEM it was possible to observe in the SRA implants a mean 2 to 7 micron gap between implant and abutment, while in the CRA implants, the gap was 7 micron. In the latter group, however, the gap was always completely filled by the fixation cement. All the spaces between abutment and implant were filled by the cement. 2) With SRA implants, it was possible to observe the presence of toluidine blue at the level of the fixture-abutment interface and the internal threads; the absorbent paper was stained in all cases. With CRA implants, the absorbent paper inside the hollow portion of the implants was never stained by toluidine blue. No penetration of toluidine blue was observed at the implant-abutment interface and inside the hollow portion of the implants. 3) In all the SRA implant assemblies, bacterial penetration was observed at the implant-abutment interface. No bacteria were detected in the hollow portion of the CRA implants. CONCLUSION: On the basis of the results obtained in the present study using 2 different implant systems, we conclude that CRA implants offer better results relating to fluid and bacterial permeability compared to SRA implants.

Immediate implantation in fresh extraction sockets. A controlled clinical and histological study in man.

BACKGROUND: Early implantation may preserve the alveolar anatomy, and the placement of a fixture in a fresh extraction socket helps to maintain the bony crest. Although a number of clinical studies exist, no histological reports show the outcome of implantation in fresh extraction sockets without the use of membranes in humans compared to implants placed in mature bone. METHODS: Forty-eight healthy patients, receiving at least 4 fixtures in each of 2 symmetrical quadrants, underwent placement of 1 experimental fixture placed in a fresh extraction socket (TI) and 1 contralateral fixture in mature bone (CI). TI were placed after atraumatical tooth extraction, with a surgical site at the apex of the socket and a tight contact between the fixture and the socket's walls, but without the use of filling materials or membranes. The flap was coronally repositioned to obtain primary wound closure. Immediately after surgical intervention, a standardized periapical radiograph was taken. Second-stage surgery was done after 6 months. Six months after the second surgery, a second standardized periapical radiograph was taken and clinical parameters (bleeding and plaque index) recorded. Marginal bone loss (MBL) from the time of implant placement to the time of fixture removal was calculated by comparing periapical radiographs. TI and CI were then removed by a hollow drill to obtain histological specimens. Non-demineralized sections were stained by acid fuchsin and toluidine blue, and by von Kossa to evaluate the degree of bone mineralization. The percentage of direct implant-bone contact (DBC) was calculated by a computerized microscopic digitizer. RESULTS: No significant differences in the clinical and radiographic parameters were observed between the 2 experimental categories. There was no statistically significant difference between TI and CI for DBC either in the maxilla or in the mandible. No connective or fibrous tissues were present around TI or CI. Bone resorption was not present in any of the histological sections. CONCLUSIONS: The present study shows that when a screw-type dental implant is placed without the use of barrier membranes or other regenerative materials into a fresh extraction socket with a bone-to-implant gap of 2 mm or less, the clinical outcome and degree of osteointegration does not differ from implants placed in healed, mature bone.

Aspartate aminotransferase activity in crevicular fluid from dental implants.

BACKGROUND: Aspartate aminotransferase (AST) is an enzyme normally confined to the cytoplasm of cells, but released to the extracellular environment upon cell death. Its levels are associated with the severity of experimental gingivitis and the loss of periodontal attachment. The aim of the present study was to investigate the presence and activity levels of AST in peri-implant crevicular fluid (PCF) from healthy and diseased endosseous implants in order to assess if AST in PCF can be further studied as a possible objective diagnostic aid in oral implantology. METHODS: Eighty-one fixtures from 81 systemically healthy subjects were divided into 3 groups, 27 healthy implants (HI), 27 implants with mucositis (MI) and 27 implants affected by peri-implantitis (PI) according to well-defined clinical and radiographic criteria. PCF was collected by the insertion of a #40 standardized endodontic paper point to the base of the crevice or pocket for 30 seconds. AST activity was determined spectrophotometrically at 25 degrees C. The results were expressed as AST Units/ml in PCF. RESULTS: An AST activity was detected in each sample from HI, MI and PI. The mean AST activity in HI was 0.26 +/- 0.16 U/ml; in MI, 0.38 +/- 0.27 U/ml; in PI, 0.62 +/- 0.29 U/ml. ANOVA showed that the difference among HI, MI, and PI was statistically significant at P <0.01 level. Post-hoc tests demonstrated that a significant difference in AST activity existed between HI/PI (t = 5.14; P<0.01) and MI/PI (t = 3.09; P<0.01). No statistically significant difference was found between HI/MI (t = 1.07; P >0.1) AST activity was significantly (P <0.01) associated with probing depth (r = 0.55), the amount of bone loss (r = 0.60) and bleeding on probing (r = 0.67). When the threshold for a positive AST test was set > or =0.4 U/ml, a sensitivity = 0.81 and a specificity = 0.74 were found in the detection of peri-implantitis; the positive predictive value was 61% and the negative predictive value was 88%. CONCLUSIONS: Within the limits of this study, our results may suggest that PCF analysis could be further investigated in longitudinal studies as a suitable diagnostic strategy in the evaluation of dental implants.

Prevalence of Actinobacillus actinomycetemcomitans and clinical conditions in children and adolescents from rural and urban areas of central Italy.

BACKGROUND: The aim of this study was to report on the prevalence of Actinobacillus actinomycetemcomitans (Aa) and the periodontal clinical conditions in children and adolescents from a rural area of central Italy compared with the ones from an urban area of the same region. METHOD: The study population consisted of 780 systemically healthy children, aged 6-14 years inhabiting the county of Chieti. 505 children attended 3 primary and 2 secondary schools from a rural area whereas 275 individuals attended 1 primary and 1 secondary school from the city of Chieti. The 2 provincial areas present a great difference in socioeconomic level and cultural background. Clinical examination consisted of recording the % of gingival sites positive for the presence of plaque (P1+), bleeding on probing (BOP+), mean probing depth (PD) from each primary or permanent tooth fully erupted in the oral cavity. Loss of periodontal attachment (AL+) was evaluated only in interproximal sites. AL+ subjects were distinguished in juvenile periodontitis (JP) prepubertal periodontis and early periodontitis (EP) patients. 8 gingival sites were microbiologically sampled in each subject and cultured, after pooling, for the presence of Aa. RESULTS: 30.3% of rural subjects, were positive for the presence of Aa, the difference from urban children (16%) being statistically significant (p=0.01) irrespective of gender and age. Aa showed a significantly (p=0.006) higher mean proportion in subgingival plaque samples from rural children (0.13% versus 0.02%). Loss of periodontal attachment in at least one site was found in 18 rural children (3.56%) (3 JP; 15 EP) and 2 urban girls (0.72%)(1 JP; 1 EP). No significant differences for AL were observed within the rural group according to the gender and age differentiation. In the urban group, both AL+ subjects were Aa+, while among children from rural areas all 3 JP and 13 EP subjects were Aa+. Rural subjects evidenced significantly worse clinical parameters with respect to urban children (% PI+ sites: p=0.000; % BOP+ sites: p=0.010; mean PD: p=0.000.) The relative risk for AL+ sites was significantly greater (2.42) in rural subjects harboring Aa in subgingival plaque. Similarly, the presence of Aa in subgingival plaque was related to a greater risk of more than 50% of BOP+ gingival sites in both rural and urban subjects (1.45 and 8.40, respectively). CONCLUSIONS: Results of this study suggest that Aa colonization in children and adolescents from central Italy is affected by socioeconomic and cultural factors; these factors also affect the periodontal condition of the subjects.

Bacteriological and clinical follow-up of periodontal pockets during a topically applied 1% metronidazole-gel therapy in patients with adult periodontitis.

The aim of this study was to evaluate the clinical and bacteriological effects of the intrasulcular application of a 1% metronidazole-gel (repeated administrations outdistanced of 7 days weeks long) currently employed in dermatological practice, to observe if a lower concentration of the chemotherapic agent could be equally effective as the 25% formulation in improving the periodontal condition of nine patients with adult periodontitis. The results showed that this regimen can modify, at a statistically significant level, the clinical (Pocket Probing Depth, Gingival Bleeding Index and Plaque Index) and bacteriological (Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and Veillonella parvula) parameters associated with adult periodontitis. The results are similar to those obtainable with a 25% Metronidazole-gel administered two times outdistanced by 7 days.

Microbiological and clinical effects of a 1% chlorhexidine-gel in untreated periodontal pockets from adult periodontitis patients.

The aim of this study was to report the microbiological and clinical effects of repeated subgingival administration of a 1% Chlorhexidine-gel in periodontal pockets from 10 patients with adult periodontitis. Results showed that the experimental treatment significantly improved clinical parameters (Plaque Index, Gingival Bleeding Index, and Pocket Probing Depth). Direct subgingival administration of Chlorhexidine-gel also produced a remarkable modification in the proportions of putative periodontopathic microorganisms, such as Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Veillonella parvula, Fusobacterium nucleatum, and Peptostreptococcus micros, in subgingival bacterial plaque from periodontitis patients.

Site-specific subgingival colonization by Actinobacillus actinomycetemcomitans in orthodontic patients.

A high prevalence of Actinobacillus actinomycetemcomitans (Aa) in subgingival plaque in patients for orthodontia already has been observed. The present study had the following aims: 1) to ascertain a direct relationship between the orthodontic appliance placement and the subgingival colonization by Aa, and 2) to determine whether the Aa growth specifically occurred on teeth with braces attached or whether the presence of orthodontic appliances could also cause the isolation of Aa in teeth free from therapeutic appliances. Twenty-four young systemically and periodontally healthy subjects with malaligned and crowded teeth in the anterior sextants of both dental arches participated in this study. After 1 session of ultrasonic scaling with oral hygiene instructions during the first experimental session, the mesiobuccal sites of the first molars and the distobuccal sites of the lateral incisors in both dental arches in each participant were subjected to clinical and microbiologic examination for the recovery of Aa. Clinical examination consisted of recording the presence of plaque and the examination of gingival bleeding on probing and probing depth. Microbiologic sampling was obtained with the insertion of 3 sterile paper points at the deepest part of each gingival sulcus. Altogether, 192 periodontal sites were examined. After the examinations, the patients received fixed orthodontic appliances in only 1 dental arch (test sites) and the other one was left free from appliances (control sites). Clinical examination and microbiologic sampling were repeated in the same experimental test and control sites after 4, 8, and 12 weeks. At the 12-week session, the orthodontic appliance was removed from the test arch, and, 4 weeks later, a further clinical and microbiologic examination was performed. The results showed that, during the period with orthodontic appliances, the presence of plaque scores and the gingival bleeding on probing scores were increased significantly and that Aa, initially absent from all but 1 subject, was isolated in 19 and 20 subjects after 4 and 8 weeks, respectively. Furthermore, no gingival sites from the control teeth (free from Aa colonization at baseline) showed positive results for the sought-after bacterium throughout the entire length of the study. It was concluded that the placement of orthodontic appliances promotes the subgingival growth of Aa; this specific microbial change is specifically restricted to subgingival plaque from orthodontic appliance-bearing teeth. The presence of orthodontic bands and brackets therefore cannot affect the microbiologic condition of the whole mouth.

[A comparative evaluation of the efficacy of the excisional new attachment procedure (ENAP) relative to root planing in the etiological phase of periodontal therapy]. / Valutazione comparativa dell'efficacia della excisional new attachment procedure (ENAP) nei confronti della levigatura radicolare nella fase etiologica della terapia parodontale.

BACKGROUND: In the present study, the effectiveness of root planing has been compared to the excisional new attachment procedure (ENAP) during the etiological phase of periodontal therapy, after the supragingival scaling, in order to establish if a technique offering an easy access to the subgingival areas could reduce the need for a surgical phase in the periodontal treatment. METHODS: Twenty-seven patients, affected by moderate periodontitis, participated in this study; in each of them root planing was performed in a half of the oral cavity (control site) and the ENAP in the other half (test site). The main clinical parameters of periodontal health (probing depth--PD-, attachment loss--AL-, plaque index--PlI- and gingival index--GI-) were evaluated before and 1, 2 and 6 months after the periodontal treatment. RESULTS: The results of the study showed that the parameters related with the amount of plaque and with the conditions of the marginal gingival tissue were not influenced by the different treatments used. Better improvements were found in PD and AL values in teeth treated by ENAP compared to those treated by root planing; this result is explained by a better access to the roots offered by the ENAP. CONCLUSIONS: We can conclude that, within the limits of the present study, the ENAP can reduce the need for a further surgical treatment of the periodontal patient.

Histologic and histomorphometric analysis of the bone response to machined and sandblasted titanium implants: an experimental study in rabbits.

The aim of this study was to make a comparative analysis between the bone response to machined and sandblasted implants. The sandblasting was done with 150-microns aluminum oxide particles. Under scanning electron microscopic examination, the machined implants presented typical machining grooves, while a very rough, highly irregular surface with depressions and indentations was present on the sandblasted implants. Light microscopy showed a different bone growth pattern on machined (implantopetal growth) and sandblasted (implantofugal growth) implants. No negative effects on the rate of bone growth were observed in spite of the presence of aluminum ions. The histomorphometric analysis showed that sandblasted implants presented, from the third week onwards, a significantly higher contact percentage (P < .0001). These values could point to higher osteoconductivity as a result of the higher surface roughness of sandblasted surfaces.

Expanded polytetrafluoroethylene and dental rubber dam barrier membranes in the treatment of periodontal intrabony defects. A comparative clinical trial.

As observed in previous case reports, dental rubber dam (DRD) can be utilized as a barrier membrane in the guided tissue regeneration (GTR) technique for the treatment of periodontal intrabony defects. The purpose of the present study was (1) to confirm the validity of DRD as a suitable material in regenerative procedures and (2) to compare, in a split-mouth clinical trial, the effectiveness of DRD-made membranes in the treatment of periodontal intrabony defects versus that of expanded polytetrafluoroethylene (e-PTFE) barriers. 22 systemically healthy non-smoker adult periodontitis patients (7 male, 15 female) aged between 35 to 58 years were selected for the study. In each patient, a couple of 2-3 wall intrabony defects, located in different quadrants, were treated by a GTR technique using DRD (test sites) and e-PTFE (control sites), respectively. Performing a strict control of the oral hygiene level and of the marginal gingival health during the whole period of study, clinical (pocket probing depth, PPD; probing attachment level, PAL; gingival recession, GR) and intrasurgical (depth of the defect's intraosseous component, IOC; level of the alveolar crest, ACL) parameters were recorded at baseline and at the 1-year re-entry procedure in each experimental site. Furthermore, the coronal level of the newly formed tissue from the base of the defect (NFTL) and the vertical bone gain (VBG) were calculated at the time of membrane removal and after the re-entry procedure respectively. Membranes were removed from both test and control sites after 5 weeks; however, exposure of the membrane always occurred in test sites whereas it was observed in only 6 out of 22 control sites, this fact leading to an incomplete coverage of the regenerated tissue by the gingival flap in 18 out of 22 test sites. In both test and control sites, a statistically significant improvement of clinical and intrasurgical parameters occurred at the end of the study period; however, a significantly greater improvement was observed in control sites for PAL (+4.0 mm versus +3.0 mm; p<0.05) and VBG (3.9 mm versus 2.9 mm; p<0.05) although at the time of membrane removal, NFTL was similar between the experimental sites (test: 5.8; control: 5.6; p>0.05). Conversely, test sites exhibited a statistically significant greater increase in gingival recession (+1.9 versus +1.2; p<0.05) and alveolar crest resorption (-1.1 versus -0.3, p<0.01) in comparison to controls. It was concluded that (1) DRD is a suitable material to be used as a barrier membrane in GTR procedures although (2) e-PTFE membranes can provide a greater improvement in PAL and VBG, probably because of the difficulty in completely covering the regenerated tissue due to the fact that the gingival tissues have undergone a consistent recession in DRD-treated sites. Further studies are needed to demonstrate if an adequate coverage of the regenerated tissue in DRD-treated sites can eliminate these differences.

[Periodontal guided tissue regeneration with a rubber dam: short term clinical study]. / Rigenerazione guidata dei tessuti parodontali con diga di gomma: studio clinico a breve termine.

BACKGROUND: The guided regeneration of periodontal tissues demonstrated to represent a therapeutical technique with predictable results. It has been observed that different materials, used as regenerative membranes, offer very similar results. Unconventional materials too, like the rubber dam, seem to be useful in the guided tissues regeneration technique. The object of the present study has been to comparatively evaluate the effectiveness of Gore-Tex and rubber dam-made membranes in the therapy of intra-osseous periodontal defects. MATERIALS AND METHODS: Six patients with two similar intra-osseous defects, participated in the study; one defect has been treated using, during the surgical intervention, a Gore-Tex membrane, while the other has received, a fragment of sterile rubber dam membranes. The principal clinical parameters of the periodontal health (probing depth -PD- and attachment loss -AL-) has been evaluated in both the defects before and 6 months after the periodontal surgery. RESULTS AND CONCLUSIONS: The results have showed that there are not statistically significant differences (p > 0.05) in the healing of the intra-osseous defects treated by rubber dam or Gore-Tex. The conclusion is drawn that the rubber dam can represent a valid and cheap alternative to the materials traditionally used in the regenerative surgery of the periodontal tissues.