Osteoblasts and Fibroblasts Interaction with a Porcine Acellular Dermal Matrix Membrane.

The use of collagen membranes has remained the gold standard in GTR/GBR. In this study, the features and the biological activities of an acellular porcine dermis collagen matrix membrane applicable during dental surgery were investigated, and also by applying hydration with NaCl. Thus, two tested membranes were distinguished, the H-Membrane and Membrane, compared to the control cell culture plastic. The characterization was performed by SEM and histological analyses. In contrast, the biocompatibility was investigated on HGF and HOB cells at 3, 7, and 14 days by MTT for proliferation study; by SEM and histology for cell interaction study; and by RT-PCR for function-related genes study. In HOBs seeded on membranes, mineralization functions by ALP assay and Alizarin Red staining were also investigated. Results indicated that the tested membranes, especially when hydrated, can promote the proliferation and attachment of cells at each time. Furthermore, membranes significantly increased ALP and mineralization activities in HOBs as well as the osteoblastic-related genes ALP and OCN. Similarly, membranes significantly increased ECM-related and MMP8 gene expression in HGFs. In conclusion, the tested acellular porcine dermis collagen matrix membrane, mainly when it is hydrated, behaved as a suitable microenvironment for oral cells.

Pressure on the Health-Care System and Intensive Care Utilization During the COVID-19 Outbreak in the Lombardy Region of Italy: A Retrospective Observational Study in 43,538 Hospitalized Patients.

During the spring of 2020, the coronavirus disease 2019 (COVID-19) epidemic caused an unprecedented demand for intensive-care resources in the Lombardy region of Italy. Using data on 43,538 hospitalized patients admitted between February 21 and July 12, 2020, we evaluated variations in intensive care unit (ICU) admissions and mortality over the course of 3 periods: the early phase of the pandemic (February 21-March 13), the period of highest pressure on the health-care system (March 14-April 25, when numbers of COVID-19 patients exceeded prepandemic ICU bed capacity), and the declining phase (April 26-July 12). Compared with the early phase, patients aged 70 years or more were less often admitted to an ICU during the period of highest pressure on the health-care system (odds ratio (OR) = 0.47, 95% confidence interval (CI): 0.41, 0.54), with longer ICU delays (incidence rate ratio = 1.82, 95% CI: 1.52, 2.18) and lower chances of dying in the ICU (OR = 0.47, 95% CI: 0.34, 0.64). Patients under 56 years of age had more limited changes in the probability of (OR = 0.65, 95% CI: 0.56, 0.76) and delay to (incidence rate ratio = 1.16, 95% CI: 0.95, 1.42) ICU admission and increased mortality (OR = 1.43, 95% CI: 1.00, 2.07). In the declining phase, all quantities decreased for all age groups. These patterns may suggest that limited health-care resources during the peak phase of the epidemic in Lombardy forced a shift in ICU admission criteria to prioritize patients with higher chances of survival.

Protective action of natural and induced immunization against the occurrence of delta or alpha variants of SARS-CoV-2 infection: a test-negative case-control study.

BACKGROUND: The evolution of SARS-CoV-2 has led to the emergence of several new variants, and few data are available on the impact of vaccination on SARS-CoV-2 variants. We aimed to assess the association between natural (previous infection) and induced (partial or complete vaccination) exposure to SARS-CoV-2 and the onset of new infection supported by the delta variant, and of comparing it with that supported by alpha. METHODS: We performed a test-negative case-control study, by linking population-based registries of confirmed diagnoses of infection with SARS-CoV-2, vaccinations against Covid-19 and healthcare utilization databases of the Italian Lombardy Region. Four hundred ninety-six persons who between 27 December 2020 and 16 July 2021 had an infection by the delta variant were 1:1 matched with citizens affected by alphavariant and 1:10 matched with persons who had a negative molecular test, according to gender, age and date of molecular ascertainment. We used a conditional logistic regression for estimating relative risk reduction of either variants associated with natural and/or induced immunization and corresponding 95% confidence interval (CI). RESULTS: Previous infection was associated with 91% (95% CI 85% to 95%) reduced relative risk of reinfection, without evidence of significant differences between delta and alpha cases (p=0.547). Significant lower vaccinal protection against delta than alpha variant infection was observed with reduced relative risk associated with partial vaccination respectively of 29% (7% to 45%), and 62% (48% to 71%) (p=0.001), and with complete vaccination respectively of 75% (66% to 82%) and 90% (85% to 94%) (p=0.003). CONCLUSIONS: Lower protection towards infections caused by the delta variant with respect to alpha variant was noticed, even after the completion of the vaccination cycle. This finding would support efforts to maximize both vaccine uptake with two doses and fulfilment with individual protection measures, especially as the delta variant is rampant worldwide presently.

Non-impacted tooth extractions and antibiotic treatment: A RCT study.

OBJECTIVES: A controlled, single-blind, randomized clinical trial was performed to evaluate usefulness of antibiotics in preventing pain and complications after tooth extractions and benefits of probiotics in reducing gastro-intestinal symptoms associated with antibiotic therapy. MATERIALS AND METHODS: A total of 159 patients were enrolled in this trial. After tooth extractions, patients were allocated to one of the groups: group 1 received postoperatively amoxicillin + clavulanic acid; group 2 received the same antibiotic therapy with an adjunctive probiotic treatment; and group 3 received neither antibiotics nor probiotics. Follow-up visits were planned at 7, 14, and 21 days after tooth extractions (T1, T2, and T3), and parameters assessed were pain, presence of abscess, edema, fever, alveolitis, trismus, pain, difficulty in daily routine activities, and gastro-intestinal symptoms. RESULTS: The number of patients reporting pain at T1 was significantly higher in the control group when compared to group 2 (p = .016), while no difference for pain intensity was observed between groups. No surgical site infection was observed in any of the groups. Intestinal symptoms seemed to be tackled by probiotic administration. CONCLUSIONS: Pain was the most important symptom in the control group. Antibiotics were not necessary after non-impacted tooth extractions, and probiotics can reduce gastro-intestinal symptoms associated with antibiotics.

A perspective on dental activity during COVID-19: The Italian survey.

OBJECTIVES: During the months of March and April 2020, Italy saw an exponential outbreak of COVID-19 epidemic. Dental practitioners were particularly limited in their routine activity, and the sole performance of urgent treatments was strongly encouraged during the peak of the epidemic. A survey among dental professionals was performed between 6th and 13th of April, in order to evaluate the status of dental practice during COVID-19 in Italy. MATERIALS AND METHODS: An online anonymous questionnaire was administered to retrieve data on the dental procedures performed, the preventive measures adopted, and the predictions on the future changes in dentistry following the pandemic. RESULTS: The survey was completed by 3,254 respondents and, according to the results obtained, dental activity was reduced by the 95% and limited to urgent treatments. The majority of the surveyed dentists employed additional personal protective equipment compared to normal routine, although in a non-negligible number of cases difficulty in retrieving the necessary equipment was reported. CONCLUSIONS: The survey provided a snapshot of dental activity during the SARS-CoV-2 outbreak. Overall, following the peak of the epidemic, it is probable that dental activities will undergo some relevant changes prior to fully restart.

Prevalence of multidrug-resistant tuberculosis in Latin America and the Caribbean: a systematic review and meta-analysis.

OBJECTIVES: To evaluate the prevalence of multidrug-resistant tuberculosis (MDR-TB) in individuals living in Latin America and the Caribbean (LAC). METHODS: We searched the MEDLINE, Embase and Literatura Latino Americana e do Caribe em Ciências da Saúde (Lilacs) databases until 08 August 2019 for all studies on the subject, without time or language restrictions. Original studies reporting the prevalence of infection with Mycobacterium tuberculosis resistant to isoniazid and rifampicin simultaneously (MDR) in LAC, the prevalence of resistance in cases with no previous treatment (new cases) and the prevalence of resistance in previously treated cases were selected. Considering the expected heterogeneity between studies, all analyses were performed using the random effects model, and heterogeneity was assessed using the I2 statistic. RESULTS: We included 91 studies from 16 countries. The estimated overall prevalence was 13.0% (95% CI 12.0-14.0%), and the heterogeneity between studies was substantial (I2  = 96.1%). In the subgroup analyses, it was observed that the prevalence of MDR-TB among new cases was 7.0% (95% CI 6.0-7.0%) and in previously treated cases was 26.0% (95% CI 24.0-28.0%). CONCLUSIONS: This review highlights multidrug resistance to antituberculosis drugs in LAC, indicating that prevention strategies have not been effective. Government institutions should invest heavily in strategies for early diagnosis and the rapid availability of effective treatments and prioritise adequate protection for health professionals. In addition, screening programmes should be adopted to prevent secondary cases.

OBJECTIFS: Evaluer la prévalence de la tuberculose multirésistante (TB-MDR) chez les personnes vivant en Amérique latine et dans les Caraïbes (ALC). MÉTHODES: Nous avons effectué des recherches dans les bases de données Medline, EMBASE et Literatura Latino Americana e do Caribe em Ciências da Saúde (Lilas) jusqu'au 08 août 2019 pour toutes les études sur le sujet, sans restriction de temps ou de langue. Des études originales faisant état de la prévalence de l'infection à Mycobacterium tuberculosis résistante à l'isoniazide et à la rifampicine simultanément (MDR) dans la région ALC, de la prévalence de la résistance dans les cas sans traitement antérieur (nouveaux cas) et de la prévalence de la résistance dans les cas précédemment traités ont été sélectionnées. Compte tenu de l'hétérogénéité attendue entre les études, toutes les analyses ont été effectuées à l' aide du modèle à effets aléatoires et l'hétérogénéité a été évaluée à l' aide de la statistique I2 . RÉSULTATS: Nous avons inclus 91 études de 16 pays. La prévalence globale était estimée à 13,0% (IC95%: 12,0%-14,0%) et l'hétérogénéité entre les études était importante (I2 = 96,1%). Dans les analyses des sous-groupes, il a été observé que la prévalence de la TB-MDR parmi les nouveaux cas était de 7,0% (IC95%: 6,0%-7,0%) et dans les cas précédemment traités de 26,0% (IC95%: 24,0%-28,0%). CONCLUSIONS: Cette revue met en évidence la multirésistance aux médicaments antituberculeux dans la région ALC, indiquant que les stratégies de prévention n'ont pas été efficaces. Les institutions gouvernementales devraient investir massivement dans les stratégies de diagnostic précoce et la disponibilité rapide de traitements efficaces et accorder la priorité à une protection adéquate pour les professionnels de la santé. De plus, des programmes de dépistage devraient être adoptés pour prévenir les cas secondaires.

Antibiotic's effectiveness after erupted tooth extractions: A retrospective study.

OBJECTIVE: The purpose of this retrospective study was to assess the influence of antibiotics on the development of alveolitis after tooth extractions. MATERIALS AND METHODS: The study population consisted of patients who had erupted tooth extractions in 3 centers. The patients' medical records were collected for several parameters. Moreover, use of antibiotics was evaluated. The primary outcome was the development of alveolitis during the postoperative period. The secondary outcome measure was the possible associations between alveolitis and other patients' characteristics. RESULTS: A total of 1579 patient charts were screened. The patients enrolled in the study were 418 (159 males and 259 females). Alveolitis was reported for 12 extraction sites (2.87%). Six were in the group of patients that received antibiotics (2.14% out of 280 patients treated with antibiotics), and six were in the group of patients that did not receive antibiotics (4.35% out of 138 patients not receiving antibiotics). None of patient-level parameters showed any significant association with the development of alveolitis. CONCLUSION: In conclusion, this study showed that the use of antibiotics after erupted tooth extractions is not useful in preventing alveolitis. Larger, prospective, and randomized studies are needed before incorporating these findings into the daily clinical practice.

Potential short-term outcome of an uncontrolled COVID-19 epidemic in Lombardy, Italy, February to March 2020.

Sustained coronavirus disease (COVID-19) transmission is ongoing in Italy, with 7,375 reported cases and 366 deaths by 8 March 2020. We provide a model-based evaluation of patient records from Lombardy, predicting the impact of an uncontrolled epidemic on the healthcare system. It has the potential to cause more than 250,039 (95% credible interval (CrI): 147,717-459,890) cases within 3 weeks, including 37,194 (95% CrI: 22,250-67,632) patients requiring intensive care. Aggressive containment strategies are required.

Clinical Success of Dental Implants Placed in Posterior Mandible Augmented With Interpositional Block Graft: 3-Year Results From a Prospective Cohort Clinical Study.

PURPOSE: The purpose of the present cohort study was to investigate the 3-year efficacy and clinical performance of implant-supported rehabilitations in posterior mandibles augmented with the sandwich osteotomy technique. MATERIALS AND METHODS: Twenty-three partially edentulous patients who developed atrophy of the posterior mandible (residual ridge height, 3 to 7 mm) were treated (32 surgical sites) with vertical bone augmentation using interpositional equine cancellous bone blocks and porcine corticocancellous bone particulate. All implants were placed 4 months after augmentation and were loaded with fixed dental prostheses. One side per patient was selected and followed for 3 years, and the patient was the unit of analysis. Linear radiographic vertical bone gain and peri-implant marginal bone loss were assessed; secondary outcomes-complication rates after surgery, prosthesis and implant failure rates, width of keratinized mucosa, and patient satisfaction-were evaluated. RESULTS: All patients reported postoperative paresthesia that resolved over a period of 2 months after the augmentation procedure. The mean vertical bone gain was 5.6 mm after 4 months. Ninety-one dental implants were positioned into the augmented areas. The global 3-year survival rate was 95.5%. The mean peri-implant marginal bone loss around implants was 1.06 ± 0.37 mm 3 years after loading, whereas the width of keratinized mucosa had an overall increase of 0.39 ± 0.36 mm. CONCLUSION: The results of the present 3-year study suggested high success rates for implants placed in areas augmented with the osteotomy sandwich technique. This surgical approach could be helpful in the presence of a low residual vertical height in the posterior mandible before implant placement.

Medication-Related Osteonecrosis of the Jaw: The Use of Leukocyte-Platelet-Rich Fibrin as an Adjunct in the Treatment.

Medication-related osteonecrosis of the jaw are bone exposures in the maxillofacial region that does not heal after 8 weeks from the observation of a health care provider in patients with history of the intake of antiresorptive agents and no previous irradiation of the craniofacial region. Initially attributed only to the intake of bisphosphonates they have later been associated also with the intake of other classes of antiresorptive medications.This retrospective study analyzed records from patients with documented medication-related osteonecrosis of the jaws treated in our unit. Clinical data, comorbidities and concurrent medications, treatment outcome information such us number of repeated treatments needed, antibiotic used, type of treatment adopted were recorded. Baseline demographics for the included records of 15 patients (mean age: 64 years) revealed a treatment success rate of 73.3% (mean observation period: 42.2 months), failure rate of 26.6%, dental extraction trigger rate of 33.3%, and a spontaneous trigger rate of 40%.Zolendronate and denosumav were the medications most frequently associated with the upset of medication-related osteonecrosis of the jaw (60% of the sample). In 8 cases out of the 11 that were successful, the surgical treatment had to be repeated more than once. Leukocyte-platelet-rich fibrin led to the resolution of 11 of the 14 cases in which it was used.

Nonsurgical Treatment of Peri-implantitis Without Eliminating Granulation Tissue: A 3-Year Study.

OBJECTIVES: The purpose of this study was to evaluate a nonsurgical approach toward peri-implantitis by means of mechanical debridement and local detoxification leaving granulation tissue into the peri-implant pockets. MATERIALS AND METHODS: An analysis was performed on the outcomes of 2 nonsurgical protocols: mechanical debridement plus chemical detoxification with 0.2% chlorhexidine and chlortetracycline hydrochloride (test), and mechanical debridement alone (control). Measures were collected at baseline, 3, 24, and 36 months after treatment. RESULTS: Seventy-five implants with peri-implantitis were included. At a 36-month evaluation, mean pocket probing depth was 3.15 ± 0.32 mm for the test group and 5.97 ± 0.90 mm for the control group, the difference being significant. An improvement of marginal bone level was recorded for the test group, whether the control group showed a further marginal bone loss. Treatment success was 100% in the test group and 31.4% in the control group. CONCLUSION: Nonsurgical implant debridement alone seemed not efficient in the treatment of peri-implantitis. Further longitudinal studies are required to evaluate the efficacy of mechanical debridement with chemical detoxification and removal of granulation tissues against mechanical debridement with chemical detoxification alone.

Regenerative properties of collagenated porcine bone grafts in human maxilla: demonstrative study of the kinetics by synchrotron radiation microtomography and light microscopy.

OBJECTIVES: Recently, it has been reported that heterologous biomaterials, where the collagen matrix is preserved, seem to facilitate blood clotting and the subsequent invasion of repairing and regenerative cells. This study aimed at evaluating the healing of human extraction sockets grafted with a collagenated cortico-cancellous porcine bone (mp3®, OsteoBiol®, Tecnoss®, Giaveno, Italy) by synchrotron radiation X-ray microtomography (microCT) and histology in order to have a 3D quantitative characterization over time. MATERIALS AND METHODS: Ridge preservation with porcine bone and collagen membrane was performed on 21 patients using a flapless approach and a secondary soft tissue closure. At the time of implant placement, six bone samples were harvested, two in the 3-month group, two in the 6-month group, one in the 12-month group post-surgery, and one spontaneously healed control, and evaluated by microCT and histology. RESULTS: MicroCT revealed that in the grafted sites there were a greater number of trabeculae, although they appeared thinner than in the control sites; these trabeculae homogenously filled the defects, suggesting an improved strength of the socket. Histology showed that over time, the amount of biomaterial decreased and the newly formed bone increased, while less dense bone with wider marrow spaces was detected in the control sample, supporting synchrotron findings. CONCLUSIONS: The morphometric data converge to indicate the suitability of porcine bone for the preservation of post-extraction sockets. CLINICAL RELEVANCE: The use of mp3 is encouraged to preserve and heal sockets.

Prevalence of hepatitis B in people living with HIV/AIDS in Latin America and the Caribbean: a systematic review and meta-analysis.

BACKGROUND: Hepatitis B virus (HBV) infection is a major cause of chronic liver disease worldwide. In immunocompromised patients, the chronicity rates of HBV infection are higher, but the rates of hepatitis Be antigen (HBeAg) and HBsAg loss and seroconversion to anti-HBe and anti-HBs are lower than those in immunocompetent subjects. This study aimed to evaluate articles on the prevalence of HBsAg in people living with human immunodeficiency virus (HIV) /AIDS (PLWHA) in Latin America and the Caribbean (LAC). METHODS: We searched the PubMed, Latin American and Caribbean Health Sciences, and Embase databases for studies up to November 2016 on infection with HIV and HBV in LAC without period or language restrictions. We did not include case reports, case series, review articles, comments, or studies with a sample size smaller than 100. We also evaluated the quality of the articles using a list of criteria totaling 21 items. RESULTS: Of the 28 selected articles (n = 18,457) published from 1999 to 2016, 18 studies (64.3%) were from Brazil, 3 (10.7%) were from Argentina, 2 (7.1%) were from Chile, 2 (7.1%) were from Cuba, 1 (3.6%) was from Colombia, 1 (3.6%) was from Venezuela, and 1 (3.6%) was from Jamaica. The mean score for the assessment of the study quality was 11.6 (range: 8-16). The estimated pooled prevalence of HBsAg among PLWHA in the selected studies was 7.0% (95% CI 7.0-7.0%). The pooled prevalence of HBsAg was 8.0% (95% CI 8.0-9.0%) in the studies published from 1999 to 2006 and 6.0% (95% CI 5.0-6.0%) in the studies published during the later timeframe. CONCLUSIONS: The results of this review indicate the need to increase the investment in preventive measures against hepatitis B, particularly when the impact of adequate vaccination in this population is considered. Future studies with larger sample sizes are needed in LAC to determine the true prevalence of hepatitis B throughout the region and to clarify and address the risk factors associated with the acquisition of infection.

The rs738409 polymorphism of the PNPLA3 gene is associated with hepatic steatosis and fibrosis in Brazilian patients with chronic hepatitis C.

BACKGROUND: Prospective studies have shown that 80% of acute hepatitis C virus (HCV) cases progress to chronic infection; approximately 10-20% of patients with these conditions will develop liver cirrhosis within 2 to 3 decades, and 1-5% will develop liver cancer. Some studies have indicated that the rs738409 polymorphism of the PNPLA3 gene is associated with steatosis and the progression of advanced fibrosis. This study assessed the contribution of the PNPLA3 rs738409 polymorphism with regard to the steatosis and degree of liver fibrosis in Brazilian patients diagnosed with chronic hepatitis C. METHODS: A total of 290 patients were evaluated at the Clinics Hospital of the School of Medicine, University of São Paulo, between 2010 and 2015. The inclusion criteria were age ≥ 18 years and positive anti-HCV antibody and HCV RNA tests. The participants were evaluated based on medical consultation, blood tests, and liver biopsies conducted before specific antiviral therapies were applied. The associations between the rs738409 PNPLA3 gene polymorphism and steatosis and advanced fibrosis were tested under a recessive inheritance model using logistic regression analysis, including age, gender, BMI, ethnicity/color, HOMA-IR, alcohol intake, HCV genotype 3, and the rs58542926 TM6SF2 gene polymorphism as covariates. RESULTS: The mean age of the patients was 54.9 years old (range, 28 to 82 years), and 124 (42.8%) patients were male; 226 (77.9%) were white, 43 (14.8%) were pardo, and 21 (7.2%) were black Brazilians. Of the patients included in this study, 133 (45.9%) presented with the CC genotype, 63 (21.7%) with the CG genotype, and 94 (32.4%) with the GG genotype of the PNPLA3 gene I148M variant. We observed that the associations between PNPLA3 rs738409 GG genotype and steatosis was significant (OR: 2.16; 95% CI 1.26-3.72). The same genotype was associated to advanced fibrosis too (OR:2.64; 95% CI 1.26-5.53). CONCLUSIONS: Associations between the rs738409 polymorphism of the PNPLA3 gene genotype GG and hepatic steatosis and advanced fibrosis were observed. Studies are still needed to clarify the influence of these polymorphisms on hepatic steatosis and degree of fibrosis among individuals diagnosed with chronic hepatitis C.

Clinical and Histological changes after ridge preservation with two xenografts: preliminary results from a multicentre randomized controlled clinical trial.

OBJECTIVES: To evaluate and compare clinical and histological changes after ridge preservation procedures with those of spontaneous healing. MATERIALS AND METHODS: Ninety patients were enrolled in the present randomized controlled clinical trial and underwent single-tooth extraction in the premolar/molar areas. Thirty sites were grafted with collagenated cortico-cancellous (coll), 30 sites with cortical (cort) porcine bone and 30 sites underwent natural healing. Primary (vertical and horizontal bone changes after 3 months) and secondary outcomes (histomorphometric after 3 months) were evaluated at implant placement. RESULTS: The vertical bone changes at the grafted sockets were significantly (p < 0.0001) lower (0.30 mm for cort group and 0.57 mm for coll group) when compared to non-grafted sockets (2.10 mm for nat group). Moreover, the width reduction of the coll (0.93 mm) and cort (1.33 mm) groups was significantly lower (p < 0.0001) than the non-grafted group (3.60 mm). The analysis of subgroups attested that when premolar and molar sites were compared, the buccal bone loss appeared to be dependent both on tooth position and grafting material employed. CONCLUSION: The ridge preservation procedures had significantly better outcomes when compared to natural healing. The biomaterials did not differ for maintenance of bone width; even though, the bone height seemed to be better preserved with the cortical porcine bone.

Odontogenic Orofacial Infections.

Acute dental abscess is a frequent and sometimes underestimated disease of the oral cavity. The acute dental abscess usually occurs secondary to caries, trauma, or failed endodontic treatment. After the intact pulp chamber is opened, colonization of the root canals takes place with a variable set of anaerobic bacteria, which colonize the walls of the necrotic root canals forming a specialized mixed anaerobic biofilm. Asymptomatic necrosis is common. However, abscess formation occurs when these bacteria and their toxic products breach into the periapical tissues through the apical foramen and induce acute inflammation and pus formation. The main signs and symptoms of the acute dental abscess (often referred to as a periapical abscess or infection) are pain, swelling, erythema, and suppuration usually localized to the affected tooth, even if the abscess can eventually spread causing a severe odontogenic infection which is characterized by local and systemic involvement culminating in sepsis syndrome. The vast majority of dental abscesses respond to antibiotic treatment, however, in some patients surgical management of the infection may be indicated. In the present work, a retrospective analysis of the patients with dental orofacial infections referred to the Unit of Dentistry and Maxillofacial Surgery of the University of Verona from 1991 to 2011 has been performed.

Bacterial adhesion on direct and indirect dental restorative composite resins: An in vitro study on a natural biofilm.

STATEMENT OF PROBLEM: Both direct and indirect techniques are used for dental restorations. Which technique should be preferred or whether they are equivalent with respect to bacterial adhesion is unclear. PURPOSE: The purpose of this in vitro study was to determine the affinity of bacterial biofilm to dental restorative composite resins placed directly and indirectly. MATERIAL AND METHODS: Five direct composite resins for restorations (Venus Diamond, Adonis, Optifil, Enamel Plus HRi, Clearfil Majesty Esthetic) and 3 indirect composite resins (Gradia, Estenia, Signum) were selected. The materials were incubated in unstimulated whole saliva for 1 day. The biofilms grown were collected and their bacterial cells counted. In parallel, the composite resin surface morphology was analyzed with atomic force microscopy. Both bacterial cell count and surface topography parameters were subjected to statistical analysis (α=.05). RESULTS: Indirect composite resins showed significantly lower levels than direct composite resins for bacterial cell adhesion, (P<.001). No significant differences were observed within the direct composite resins (P>.05). However, within the indirect composite resins a significantly lower level was found for Gradia than Estenia or Signum (P<.01). A partial correlation was observed between composite resin roughness and bacterial adhesion when the second and particularly the third-order statistical moments of the composite resin height distributions were considered. CONCLUSIONS: Indirect dental restorative composite resins were found to be less prone to biofilm adhesion than direct composite resins. A correlation of bacterial adhesion to surface morphology exists that is described by kurtosis; thus, advanced data analysis is required to discover possible insights into the biologic effects of morphology.

Submerged flapless technique vs. conventional flap approach for implant placement: experimental domestic pig study with 12-month follow-up.

OBJECTIVES: The aim of our study was to compare osseointegration and peri-implant crestal bone resorption in submerged flapless and conventional flap surgery over a 12-month follow-up. MATERIALS AND METHODS: The study used five domestic pigs. Implants were inserted 9 weeks after tooth extraction. Each animal received six implants in the mandible, following a split-mouth design: one side was treated using a flapless technique using mini-incisions, while a flap was raised on the other. The animals were sacrificed at 2 weeks, 1, 3, 6 and 12 months after implant placement. Radiographic images were taken to analyze crestal bone loss, and samples were extracted for histopathological and bone-to-implant contact (BIC) analyses. RESULTS: Significantly, greater crestal bone loss (P = 0.005) was obtained in the flap group compared with the flapless group. The flapless group presented significantly higher percentages of BIC (P < 0.05) at 3, 6 and 12 months compared with the conventional flap group. CONCLUSIONS: Within the limitations of this experimental animal study, it may be concluded that the type of surgery (flap or flapless) affects peri-implant bone preservation and osseointegration of regular platform implants. Flapless surgery is associated with peri-implant crestal bone preservation. Flapless surgery in combination with submerged implants allows higher osseointegration values.

Volumetric analysis of remodelling pattern after ridge preservation comparing use of two types of xenografts. A multicentre randomized clinical trial.

OBJECTIVES: The aim of this randomized clinical trial was to analyse and compare the volumetric changes after ridge preservation procedures using two different biomaterials and to evaluate associations between outcome variables and pristine three-dimensional aspects of the ridges. MATERIALS AND METHODS: Twenty-eight patients subjected to single-tooth alveolar ridge preservation were enrolled in the present multicentre, single-blind, prospective and randomized clinical trial. Fourteen sites were randomly allocated to each experimental group. The experimental sites were grafted with pre-hydrated collagenated cortico-cancellous porcine bone (coll group) or with a cortical porcine bone (cort group) and a collagen membrane; a secondary soft tissue healing was obtained for all experimental sites. Plaster casts were scanned (preoperative, at 1 and 3 months postoperative). Analysis of volumes and areas was performed, and all measured variables were statistically compared. RESULTS: Intragroup analyses at 3 months revealed that when examining changes related to three-dimensional features of remodelling patterns (volume, surfaces, height and shape), the two biomaterials showed similar behaviours with a minor loss in volume and ridge surface. Intergroup analysis at 3-month survey revealed that volume resorption of the coll group (244 mm3 ) was significantly lower (P = 0.0140) than that of the cort group (349 mm3 ). The reduction for basal surface appeared significantly different between the two groups at 1-month survey only (P = 0.0137), while the final basal surface reduction was 4.9 and 12.2 mm2 for coll and cort group, respectively. The superior surface reduction was 40.8 mm2 for coll and 50.7 mm2 for cort group, with no significant difference between the two groups. CONCLUSION: At the 3rd month analysis, coll group showed a significantly lower reduction of ridge volume and a significantly smaller shrinkage of the basal area when compared to the cort group; moreover, the coll group experienced a smaller superior surface shrinkage when compared to the cort group, even though no significance was evaluated.