Evaluation of Behavior of Castable versus Machined Solid Abutments for Morse Tapper Implant Connection: A Clinical Retrospective Study.

Objective: The primary objective of the present retrospective clinical study was to evaluate and compare the clinical performance presented by castable abutments developed for the MT system versus intermediate machined abutments, specifically regarding prosthetic or implant fractures/loss; the secondary objective was to verify the looseness of the abutments and the behavior of the peri-implant soft tissues. Methods: This clinical retrospective study was conducted on patients rehabilitated between 2019 and 2020. Inclusion criteria were patients in good general health, with an implants-supporting single crown; with solid machined abutments (control group) or castable UCLA abutments; with a connection portion (base) machined in cobalt-chrome (test group) over Morse taper DuoCone implants in the posterior mandible area; and at least two years in function. Clinical assessment was carried out by the same professional, considering the following parameters: (A) prosthetic: (i) loosening of the fixation screw, (ii) fracture of the screw and (iii) the number of times the patient had some type of complication after the installation of the prostheses were evaluated; (B) biological: (i) without keratinized mucosa (KM), (ii) 1 mm or less, (iii) between 1 and 2 mm and (iv) greater than 2 mm of KM width; and the presence or absence of mucositis. Furthermore, radiographic evaluation was performed in order to assess the marginal bone loss. These evaluations permitted to compare the groups analyzed and patients enrolled. Data were statistically analyzed, with the level of significance set at α = 0.05. Results: 79 patients with 120 MT implants were evaluated (80 castable UCLA abutments and 40 machined solid abutments). The follow-up was from 2 to 4 years. There was a 100% implant survival rate. Therefore, the control group showed two fractured abutments (5%) and no abutment loosening (95% for prosthetic survival rate), whereas the test group showed no abutment fracture but nine loosening screws (11.3%) (100% for prosthetic survival rate). Keratinized mucosa was considered thin or absent in 19 implants in the control group (47.5%) and 42 in the test group (52.5%). Mucositis was found in 11 implants in the control group (27.5%) and 27 in the test group (33.8%). A positive correlation was observed between the width of keratinized mucosa and mucositis (r = 0.521, p = 0.002). The mean marginal bone loss was 2.3 mm, ranging from 1.1 to 5.8 mm. No correlation was observed when considering marginal bone loss versus the three parameters (implant diameter, implant length and time of the prosthesis in function). Conclusions: The results suggest that UCLA-type abutments are a viable option for rehabilitating implants with Morse taper connections, suggesting lower fracture risk. Further research is necessary to confirm these findings and thoroughly evaluate the clinical performance and long-term outcomes.

Multivariate analysis of the influence of peri-implant clinical parameters and local factors on radiographic bone loss in the posterior maxilla: a retrospective study on 277 dental implants.

OBJECTIVES: The aim of the present study was to investigate whether peri-implant clinical parameters (modified plaque index (mPI), bleeding and/or suppuration on probing (B/SOP)) and local factors (type of prostheses, screw emergence, platform diameter, and abutment angulation) might contribute to the development of additional bone loss and peri-implantitis around dental implants. MATERIALS AND METHODS: Two hundred seventy-seven external hex connection implants placed in the posterior maxilla of 124 patients were retrospectively evaluated. They were divided into two groups: physiologic bone loss < 2 mm (PBL) or additional bone loss ≥ 2 mm (ABL). GEE logistic regression was applied to evaluate the influence of type of prostheses (implant-supported single crown (ISSC), fixed partial denture (ISFPD), and full denture (ISFD)) and clinical parameters (mPI and S/BOP) on bone loss. RESULTS: Among the 277 implants, 159 (57.4%) presented PBL and 118 (42.6%) presented ABL. Within the ABL group, 20.6% implants were diagnosed with peri-implantitis. mPI significantly correlated with the type of prosthesis and the highest value of mPI (index = 3) was observed in ISFD (23.8%). Moreover, peri-implantitis was more frequently associated with ISFD (32.79%) than ISSC and ISFDP (13.79% and 13.48, respectively) CONCLUSIONS: ISFD in the posterior maxilla presented high rates of ABL and showed a higher prevalence of peri-implantitis. None of the local factors seemed to contribute to the development of these conditions. Further investigations are needed to prospectively support the results of the present study. CLINICAL RELEVANCE: Patients rehabilitated with ISFD should be carefully monitored and have more frequent maintenance visits to prevent or control peri-implant bone loss.

The impact of generic labels on the consumption of and adherence to medication: a randomized controlled trial.

Background: Although generic drugs are pharmacologically equivalent to their brand-name counterparts, prejudices against them remain strong. We assess the extent to which generic (versus brand-name) labels affect patients' consumption of and adherence to medication. Methods: One hundred one patients who received dental implants agreed to participate in a study. In a pre-surgery survey, most patients reported a positive view about generic drugs. After dental surgery, the patients were prescribed a once-daily analgesic regimen (50 mg tramadol hydrochloride) for up to 7 days. All the patients received at no cost the same brand-name medication with either a brand-name label (n = 51) or a generic label (n = 50) and were informed of the retail prices associated with both labels. Telephone follow-up was conducted 24 hours, four days, and seven days after surgery to assess the number of prescribed pills consumed and when their use was discontinued, the number of non-prescribed pills consumed, pain levels throughout the follow-up period, the perceived efficacy of the analgesic, and the willingness to recommend it to a friend. Results: The label manipulation impacted the participants' behaviour and subjective assessments. Discontinuation before the end of the 7-day period was more frequent under the generic (vs. brand-name) label condition. The patients in the generic label group were also more likely to consume non-prescribed pills (non-adherence). Additionally, the patients in the generic label group reported higher levels of pain. Conclusion: Generic labels may negatively affect adherence to treatment even if patients report ex ante positive evaluations of the quality of generics drugs.

Evaluation of the Effect of Air Polishing With Different Abrasive Powders on the Roughness of Implant Abutment Surface: An In Vitro Study.

The aim of this in vitro study was to evaluate the effect of air polishing on the implant abutment surface using different abrasive powders: sodium bicarbonate and amino acid glycine. Fifteen grade III machined surface titanium disks with 8-mm diameter and 2-mm thickness were divided in 3 groups of 5 samples each and subjected to air polishing for 20 seconds with an Ultrajet Flex air-abrasive device and a distinct prophylaxis protocol: air and water (G1); air, water, and sodium bicarbonate (G2); and air, water; and amino acid glycine (G3). After the air polishing, the average roughness (Ra) of the samples was measured using an optical profilometer, and the obtained data were statistically analyzed. We found that G1 and G3 had similar Ra, while Ra values for G2 were significantly higher. This study demonstrated that air-polishing powders containing glycine had less of an effect on the roughness of the surface of titanium disks compared with sodium bicarbonate powders. Future in vivo studies will be conducted to investigate the clinical relevance of the present results.

Mechanical Complications Related to the Retention Screws of Prefabricated Metal Abutments With Different Angulations: A Retrospective Study With 916 Implants.

OBJECTIVES: The present retrospective study assessed the clinical performance of abutment screws from prefabricated metal abutments and compared technical complication rates between straight and angled abutments. MATERIALS AND METHODS: Dental charts were selected for patients with dental implant rehabilitations delivered between 1998 and 2012. Abutment angulation, prosthetic screw type, and presence of complications that occurred during the selected time period were collected. Technical complications registered included abutment screw loosening and/or fractures detected during clinical and radiographic examinations. The chi-square test was used for statistical analysis. RESULTS: Abutment angulations were divided into 2 groups: G1) prefabricated straight abutments and G2) prefabricated angled conical mini UCLA-type abutments. A total of 916 implants (799 straight and 117 angled conical mini UCLA-type abutments) were evaluated. G1 showed 91.1% had absence of failures, which were clinically defined as any screw loosening or fracture; and 8.9% reported some type of technical complication. G2 showed 92.3% and 7.7%, with and without technical complications, respectively. CONCLUSIONS: No significant differences were observed between abutment angulation and technical complications.

Risk indicators for Peri-implantitis. A cross-sectional study with 916 implants.

OBJECTIVES: The aim of this study was to identify systemic and local risk indicators associated with peri-implantitis. MATERIAL AND METHODS: One hundred eighty-three patients treated with 916 osseointegrated titanium implants, in function for at least 1 year, were included in the present study. The implants were installed at the Foundation for Scientific and Technological Development of Dentistry (FUNDECTO) - University of Sao Paulo (USP) - from 1998 to 2012. Factors related to patient's systemic conditions (heart disorders, hypertension, smoking habits, alcoholism, liver disorders, hepatitis, gastrointestinal disease, diabetes mellitus I and II, hyperthyroidism or hypothyroidism, radiation therapy, chemotherapy, menopause, osteoporosis, active periodontal disease, history of periodontal disease and bruxism), implant's characteristics (location, diameter, length, connection, shape, and antagonist), and clinical parameters (wear facets, periodontal status on the adjacent tooth, plaque accumulation on the adjacent tooth, modified plaque index, sulcus bleeding index, probing depth, bleeding on probing, width of keratinized tissue and marginal recession). RESULTS: An increased risk of 2.2 times for history of periodontal disease (PD), 3.6 times for cemented restorations compared to screw-retained prostheses, 2.4 times when wear facets were displayed on the prosthetic crown and 16.1 times for total rehabilitations when compared to single rehabilitations were found. Logistic regression analysis did not show any association between the implant's characteristics and peri-implantitis. CONCLUSIONS: A history of periodontal disease, cemented prostheses, presences of wear facets on the prosthetic crown and full mouth rehabilitations were identified as risk indicators for peri-implantitis. Implants' characteristics were not related to the presence of peri-implantitis.

Analysis of Effectiveness of Different Rotational Instruments in Implantoplasty: An In Vitro Study.

OBJECTIVE: To analyze the temperature increase in the implant, adjacent bone, procedure time, and roughness provided by different rotatory instruments in the implantoplasty procedure. MATERIAL AND METHODS: Three types of rotational instruments were used to evaluate the implant surface wear, divided according to their surface features: Group 1 (G1) diamond, Group 2 (G2) tungsten carbide, and Group 3 (G3) multilaminar. For the roughness test, a control group was included for comparison with the test groups. RESULTS: The temperature variation was statistically significant in the implant (P < 0.05) where G2 showed the lowest variation. There was no statistically significant difference between the 3 groups regarding the temperature increase measured in the bone (P > 0.05). The difference of wear time was statistically significant (P < 0.05) with faster results for G3. In the surface roughness analyses, there was a statistically significant difference (P < 0.05) between the control group and the test groups. Among the 3 test groups, the difference between measurements was not statistically significant (P > 0.05). CONCLUSION: All tested rotatory instruments performed the same level of surface roughness in the implantoplasty. The tungsten carbide bur caused a minor change in the implant temperature. The multilaminar bur performed a faster wear time. More in vivo studies are necessary to conclude which is the best rotatory instrument for implantoplasty.

Prevalence of Peri-implant Diseases: Analyses of Associated Factors.

UNLABELLED: AIM. Identify the relationship between specific factors (age, sex, smoking, time of prosthesis in function, implant location, and width of peri-implant keratinized mucosa) and peri-implant diseases in patients from the Center of Research and Continuing Education in Implant Dentistry (CEPID) at the Federal University of Santa Catarina (UFSC), Brazil. MATERIALS AND METHODS: A cross-sectional study was conducted in 193 patients that had received 725 external-hexed cylindrical implants supporting functional prosthesis for at least 1 year (range from 1-9 years). Clinical examination included probing depths, bleeding on probing and/or suppuration. Radiographic exam was conducted to measure peri-implant bone levels. RESULTS: There was no statistically significance in the association between prevalence of peri-implant diseases and age, sex, time with prostheses in function and implant location variables independently. There was a statistically significant association between the independent variables of smoking and the width of keratinized peri-implant mucosa less than 2mm, and the presence of peri-implant diseases. When all the categories were evaluated together in relation with the peri-implant diseases, the prostheses in function for 5 years and more had association with presence of both, peri-implant mucositis an peri-implantitis. Peri-implantitis prevalence was higher for males with the prostheses in use for 5 years or more. Peri-implant mucositis was more associated with the participants over 57 years of age, with systemic disease and with the prostheses in function for more than 5 years. CONCLUSIONS: Smoking habits and the width of peri-implant keratinized mucosa as independent variables were associated with the prevalence of peri-implant diseases.

Clinical and Radiographic Outcomes of Resective Surgery with Adjunctive Implantoplasty Over a 6- to 11-Year Follow-up: A Case Series.

OBJECTIVES: The aim of the present case series is to exhibit the long-term clinical and radiographic outcomes of resective surgery with adjunctive implantoplasty over a 6-to-11-year follow-up. MATERIALS AND METHODS: Four patients presenting 4 implants diagnosed with peri-implantitis according a to an established case definition were included in the present case series. Subjects underwent resective surgery, a modified implantoplasty approach, and implant surface decontamination. Clinical and radiographic outcomes such as bleeding on probing (BOP), suppuration on probing (SoP), probing depth (PD), marginal recession (MR), modified plaque index (mPI), and marginal bone levels (MBL) were recorded over a long-term following surgical therapy. RESULTS: Over 6-to-11-year follow-up, mean BOP, PD, and SoP scores amounted to 17 ±24%, 2.5 ±1.26 mm, and 0%, respectively. BOP scores were reduced in 17%, PD values in 2.5mm, and SoP scores in 100%. Radiographic analysis revealed a mean radiographic bone gain of 3.1 ± 1.84 mm. Peri-implant marginal bone loss surface area decreased by 5.7±3.77mm2 over the long-term follow-up. CONCLUSION: Resective therapy with adjunctive implantoplasty promoted favorable clinical and radiographic outcomes at peri-implantitis treated sites over a long-term period. CLINICAL RELEVANCE: Diverse surgical approaches such as resective, reconstructive, and combined therapy have been proposed towards peri-implantitis treatment. A resective surgical approach with an adjunctive "modified" implantoplasty refers to the modification of the implant body into a constricted area to mimic a "waist" silhouette. This modified technique conforms an adequate concave smooth area that may favor the outcomes of resective surgical therapy for soft tissue adaptation, biofilm control, and possible peri-implant bone gain over the long term.

Marginal Bone Level and Biomechanical Behavior of Titanium-Indexed Abutment Base of Conical Connection Used for Single Ceramic Crowns on Morse-Taper Implant: A Clinical Retrospective Study.

The goal of this retrospective clinical study was to evaluate the behavior of Morse-taper indexed abutments by analyzing the marginal bone level (MBL) after at least 12 months of function. Patients rehabilitated with single ceramic crowns between May 2015 and December 2020 received single Morse-taper connection implants (DuoCone implant) with two-piece straight abutment baseT used for at least 12 months, presenting periapical radiograph immediately after crown installation were enrolled. The position of the rehabilitated tooth and arch (maxilla or mandible), crown installation period, implant dimensions, abutment transmucosal height, installation site (immediate implant placement or healed area), associated with bone regeneration, immediate provisionalization, and complications after installation of the final crown were analyzed. The initial and final MBL was evaluated by comparing the initial and final X-rays. The level of significance was α = 0.05. Seventy-five patients (49 women and 26 men) enrolled had a mean period of evaluation of 22.7 ± 6.2 months. Thirty-one implant-abutment (IA) sets had between 12-18 months, 34 between 19-24 months, and 44 between 25-33 months. Only one patient failed due to an abutment fracture after 25 months of function. Fifty-eight implants were placed in the maxilla (53.2%) and 51 in the mandible (46.8%). Seventy-four implants were installed in healed sites (67.9%), and 35 were in fresh socket sites (32.1%). Thirty-two out of these 35 implants placed in fresh sockets had the gap filled with bone graft particles. Twenty-six implants received immediate provisionalization. The average MBL was -0.67 ± 0.65 mm in mesial and -0.70 ± 0.63 mm in distal (p = 0.5072). The most important finding was the statistically significant difference comparing the values obtained for MBL between the abutments with different transmucosal height portions, which were better for abutments with heights greater than 2.5 mm. Regarding the abutments' diameter, 58 had 3.5 mm (53.2%) and 51 had 4.5 mm (46.8%). There was no statistical difference between them, with the following means and standard deviation, respectively, -0.57 ± 0.53 mm (mesial) and -0.66 ± 0.50 mm (distal), and -0.78 ± 0.75 mm (mesial) and -0.746 ± 0.76 mm (distal). Regarding the implant dimensions, 24 implants were 3.5 mm (22%), and 85 implants (78%) had 4.0 mm. In length, 51 implants had 9 mm (46.8%), 25 had 11 mm (22.9%), and 33 implants were 13 mm (30.3%). There was no statistical difference between the abutment diameters (p > 0.05). Within the limitations of this study, it was possible to conclude that better behavior and lesser marginal bone loss were observed when using abutment heights greater than 2.5 mm of transmucosal portion and when placed implants with 13 mm length. Furthermore, this type of abutment showed a little incidence of failures within the period analyzed in our study.

Comparative analysis of the mechanical limits of resistance in implant/abutment set of a new implant design: An in vitro study.

OBJECTIVE: The aim of the present in vitro study was to evaluate the resistance on quasi-static forces and in the fatigue mechanical cycling of a new implant design compared to two other conventional implant designs. MATERIALS AND METHODS: Eighty-eight implants with their respective abutments were tested and distributed into four groups (n = 22 per group): Morse taper connection implant (MT group), conventional external hexagon implant (EH con group), new Collo implant of external hexagon with the smooth portion out of the bone insertion (EH out group), and new Collo implant of external hexagon with the implant platform inserted to the bone level (EH bl group). All the sets were subjected to quasi-static loading in a universal testing machine, and we measured the maximum resistance force supported by each sample. Another 12 samples from each group were submitted to the cyclic fatigue test at 4 intensities of forces (n = 3 per force): 80%, 60%, 40%, and 20%. The number of cycles supported by each sample at each force intensity was evaluated. RESULTS: The three groups of implants with external hexagon connection had similar maximum strength values of the sets (p > 0.05). Meanwhile, samples from the MT group showed the highest resistance values in comparison to the other three groups (p < 0.05). In the fatigue test, the Collo out group supported a smaller number of cycles that led to the fracture than the other 3 groups proposed at loads of 80%, 60%, and 40%, and only at the load value of 20% all groups had the same performance. CONCLUSIONS: Within the limitations of the present in vitro study, the results showed that the new Collo implant performs better when installed at bone level.

Prevalence, risk indicators, and clinical characteristics of peri-implant mucositis and peri-implantitis for an internal conical connection implant system: A multicenter cross-sectional study.

BACKGROUND: Peri-implant disease prevalence is associated with a multifactorial etiology and distinct clinical characteristics of inflammation. METHODS: The present study aimed to assess the prevalence of peri-implant diseases, identify related risk indicators, and associate specific clinical characteristics to peri-implant biological complications in the medium term. Peri-implant diseases were classified according to established case criteria. Patients' data, implant and/or prosthetic features, and maintenance records were collected. Clinical characteristics such as bleeding on probing (BOP), suppuration (SUPP), keratinized mucosa (KM), probing depth (PD), marginal recession (MR), and modified plaque index (mPI) were recorded. RESULTS: Ninety-nine patients with 266 implants with a mean functional duration of 30.26 months were evaluated. Peri-implant mucositis and peri-implantitis prevalence totaled to 49.5% and 15.15% (patient level), respectively. Peri-implant mucositis was associated with osteoporosis (odds ratio [OR] 6.09), age (OR 0.97), diabetes mellitus (OR 3.09), cemented-retained prosthesis (OR 3.81), and partial prosthesis (OR 2.21). Peri-implantitis was associated with osteoporosis (OR 7.74) and periodontitis (OR 2.74), cemented prosthesis (OR 10.12), partial and full arch prostheses (OR 12.35 and 19.86), implant diameter (OR 3.64), abutment transmucosal height (OR 3.39), and hygiene difficulty (OR 3.14). Furthermore, mPI score 3 (OR 3.27) and PD scores (OR 1.64) were associated with peri-implant mucositis, while mPI score 3 (OR 16.42), KM (OR 1.53), PD (OR 1.81), MR (OR 2.61), and the relationship between KM and PD (OR 0.63) were associated with peri-implantitis. CONCLUSION: In the medium term, peri-implant diseases were correlated with factors inherent to the patient's conditions, presurgical treatment plan, and hygiene maintenance care. The knowledge of the mentioned factors and featured clinical characteristics can be crucial for disease prevention and establishment of a superior implant therapy prognosis.

Adverse effects of antipsychotic drugs: survey of doctors' versus patients' perspective.

AIMS: Almost no data are available on whether patients and doctors have similar or dissimilar opinions on the presence and level of distress due to antipsychotic adverse effects. The aim of this survey is to compare doctors' versus patients' perspective on the presence and level of distress due to antipsychotic adverse effects in a sample of patients under the care of the South-Verona mental health services. METHODS: All patients exposed to antipsychotic drugs during a census period of 6 months were identified. For each included subject, socio-demographic, clinical and treatment data were extracted. Patients' perspective on antipsychotic adverse effects was measured by means of the Liverpool University Neuroleptic Side Effect Rating Scale (LUNSERS). The LUNSERS was similarly employed to measure doctors' perspective on antipsychotic adverse effects. RESULTS: During the recruitment period, 243 patients taking antipsychotic drugs were enrolled. The correlation between the total LUNSERS score reported by patients and doctors was very low (correlation coefficient 0.22, 95% confidence interval 0.15-0.30). On average, patients perceived more adverse effects and with a significant higher distress than doctors. Multivariate analyses found no factors simultaneously associated with both patient and doctor ratings of adverse effects. CONCLUSION: Our study suggests that doctors, researchers and health care providers should increasingly consider patient and doctor perspectives as two complementary dimensions that may provide different insights in the evaluation of antipsychotic drugs. Integrating different points of view may represent a way to develop a better therapeutic alliance that might decrease the likelihood of nonadherence.

Relationship between smoking and bleeding on probing.

The objective of this study was to assess and compare bone loss (BL) around the dental implant platform as well as the presence of bacterial plaque (PBP), bleeding on probing (BOP), and periodontal probing depths (PD) of teeth and dental implants of smokers and nonsmokers. Three hundred forty-seven teeth and 98 implants of 20 randomly selected patients were assessed (12 smokers and 8 nonsmokers). The specimens were divided into 4 groups according to the site probed. Group 1 included smoker implant sites, group 2 included smoker tooth sites, group 3 included nonsmoker implant sites, and group 4 included nonsmoker tooth sites. The presence/absence of visible bacterial plaque, presence/absence of BOP, PD ≤ 3 mm or >3 mm, and BL around the dental implant platform were the data assessed. The PBP and BL showed statistical significance between smokers and nonsmokers. Bleeding on probing and PD ≤ 3 mm showed statistical significance between groups 1, 3, and 4. Comparing sites with BOP and PD > 3 mm, there was no statistical significance except for group 1, which did not present sites with these characteristics. Comparing sites with BOP and PD ≤ 3 mm, there was statistical significance between group 2 and groups 3 and 4. When comparing the prevalence of sites without BOP and PD > 3 mm, there was statistical significance between groups 1, 3, and 4. Smoking promotes a greater BL around the dental implant platform and results in vasoconstriction of the peri-implant and periodontal tissues.

Accident in implant dentistry: involuntary screwdriver ingestion during surgical procedure. A clinical report.

Although unusual, foreign body ingestion occurs in dentistry and may result in serious complications, such as intestinal perforation. The presence of the foreign body should be confirmed with the use of radiographs. The exam will allow the correct diagnosis and the treatment to be conducted according to the specific situation of the object in the gastrointestinal (GI) tract. The orientation of the patient as well as the awareness of the patient's medical history are key factors in preventing serious complications. Generally, instruments that enter the GI tract pass asymptomatically and atraumatically within 4 days to 2 weeks. Sometimes, a surgical approach is necessary to remove the instrument when there is bleeding, obstruction, or impaction in the GI tract. Thus, a correct diagnosis is vital to avoid unnecessary surgical interventions. The aim of this article is to report an accidental ingestion of a screwdriver by a patient who had previously undergone a hemi-mandibulectomy and its medical resolution.

Are sectioning and soldering of short-span implant-supported prostheses necessary procedures?

The aim of this study was to evaluate the fit between dental abutments and the metal framework of a 3-unit fixed prosthesis screwed to two implants to determine whether sectioning and soldering of the framework are in fact necessary procedures. The study was based on a model of a metal framework of a 3-unit prosthesis screwed to two implants. A total of 18 metal frameworks were constructed and divided into 3 groups: (1) NS group - each framework was cast in one piece and not sectioned; (2) CS group - the components of each sectioned framework were joined by conventional soldering; and (3) LW group - the components of each sectioned framework were joined by laser welding. The control group consisted of six silver-palladium alloy copings that were not cast together. Two analyses were mperformed: in the first analysis, the framework was screwed only to the first abutment, and in the second analysis, the framework was screwed to both abutments. The prosthetic fit was assessed at a single point using a measuring microscope (Measurescope, Nikon, Japan) and the marginal gap was measured in micrometers. Statistical analysis was performed using analysis of variance (ANOVA), Scheffe's test, Student's t-test, and Mann-Whitney U test. The NS group had larger marginal gaps than the other groups (p<0.01), while the CS and LW groups had a similar degree of misfit with no significant difference between them. The results revealed that, in the case of short-span 3-unit fixed prostheses, the framework should be sectioned and soldered or welded to prevent or reduce marginal gaps between the metal framework and dental abutments.

Effects of the Healing Chambers in Implant Macrogeometry Design in a Low-Density Bone Using Conventional and Undersized Drilling.

BACKGROUND: The ideal installation technique or implant macrogeometry for obtaining an adequate osseointegration in low-density bone tissue follows a challenge in the implantology. AIMS AND OBJECTIVE: The aim of the present study was to evaluate the behavior of three osteotomy techniques and two implant macrogeometries in two low-density polyurethane blocks. The insertion torque (IT), initial stability, pullout resistance, and weight of the residual bone material deposited on the implants were assessed. MATERIALS AND METHODS: A total of 120 implants with two different macrogeometries were used. They were divided into six groups according to the implant macrogeometry and the drilling technique performed (n = 20 implants per group). The implants were installed in polyurethane blocks with pounds per cubic foot (PCF) 10 and PCF 20 densities. The IT, initial stability, pullout resistance, and weight residual bone were measured. RESULTS: Differences were found in the values referring to the macrogeometry of the implants and the type of osteotomy performed. In all groups, the initial stability of the PCF 10 blocks was quite low. The undersized osteotomies significantly increased the values measured in all tests in the PCF 20 density blocks. CONCLUSIONS: In conclusion, even when a modified (undersized) osteotomy technique is used, implants inserted in low-quality bone (type IV) can present problems for osseointegration due their low initial stability and bone resistance. However, the modification in the implant macrogeometry (with healing chambers) presented more quantity of bone on the surface after the pullout test.

Increasing the Thickness of the Collagen Xenogeneic Matrix Prevents Early Matrix Degradation and Improves the Proliferation, Adhesion, and Viability of Human Gingival Fibroblasts and Mesenchymal Stem Cells.

Using autogenous grafts in mucogingival surgeries is related to postoperative morbidity and limited tissue availability, and thus xenogeneic matrices are increasingly used. This in vitro study evaluated the influence of xenogeneic collagen matrix thickness on cell adhesion, morphology, viability, proliferation, and matrix degradation. Matrices were divided into three groups: SLC: single layer of Lumina Coat, as commercially available (2-mm thickness); DLC: double layer of SLC (Lumina Coat); and MG: single layer of Mucograft, as commercially available (4-mm thickness). SEM was used to evaluate the matrix surface topographies. To evaluate the cell viability, proliferation, adhesion, and morphology, human gingival fibroblasts (HGF) and stem cells from human exfoliated deciduous teeth (SHED) were used. Cell viability was evaluated through MTS colorimetric method evaluating HGF and SHED on days 1, 3, and 7. Cell proliferation was assessed by PicoGreen assay, evaluating HGF and SHED on days 3 and 7. Sample degradation was evaluated on days 1, 3, 7, 14, 21, 28, and 35. All groups were biocompatible for HGF and SHED, showing viabilities > 70% on days 1, 3, and 7. DCL promoted HGF viabilities similar to MG (P = .2828) and the highest SHED viability (P < .0001) on day 1. DLC also demonstrated HGF and SHED proliferations higher than the positive control (MG; P < .05) on day 7. SLC was completely degraded on day 14, while DLC and MG presented 48.41% and 20.52% of their initial mass, respectively, on day 35. Increasing the matrix thickness improved HGF and SHED viability and proliferation and prevented early matrix degradation. DLC demonstrated better results than SLC and MG concerning matrix degradation and HGF and SHED viability and proliferation.

Histologic and histomorphometric analysis of two biomaterials of xenogenous origin for maxillary sinus elevation: a clinical study.

Objective: This study analyzed two xenogenous biomaterials based on deproteinized bovine bone mineral applied for maxillary sinus elevation. Method and materials: Fourteen patients were submitted to maxillary sinus augmentation with one of the following biomaterials: Criteria Lumina Bone Porous (test group) or Geistlich Bio-Oss (control group), both of large granules (1 to 2 mm). After 6 months, trephine biopsies were collected at the time of implant placement: 27 samples (11 patients) in the test group; 7 samples (3 patients) in the control group. Biopsies were analyzed by descriptive histology and histomorphometry, in which the percentages of newly formed bone, residual biomaterial particles, and connective tissue were evaluated. Results: Histomorphometry showed means for test and control groups, respectively, of 32.41% ± 9.42% and 26.59% ± 4.88% for newly formed bone, 22.89% ± 4.58% and 25.00% ± 4.81% for residual biomaterial, and 44.70% ± 9.54% and 48.41% ± 3.36% for connective tissue. There were no differences between groups (P > .05). Conclusion: This study concluded that Criteria Lumina Bone Porous presented similar histologic and histomorphometric characteristics to Geistlich Bio-Oss 6 months after sinus elevation surgery, identifying the tested biomaterial as an interesting alternative for bone augmentation in the maxillary sinus.

Effect of Flavonoid Supplementation on Alveolar Bone Healing-A Randomized Pilot Trial.

We investigated the effects of two common dietary supplements on bone healing in dental extraction sockets in humans. In this randomized pilot trial, male subjects took Grape Seed Extract [GSE] or Grapefruit Extract [GFE] starting two weeks prior to dental extraction and maintained this regimen for sixty days after surgery. Extraction sockets were filled with a collagen plug. After 24 h, a socket sample was collected and processed for quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and an 84-gene wound healing assay. Sixty days after tooth extraction, a core of newly formed bone was obtained prior to dental implant placement and processed for histology. qRT-PCR revealed that GFE led to a significant decrease in platelet-derived growth factor and interleukin (IL)1-ß compared to GSE, and a significant decrease in IL-6 and CXCL2 compared to control. GSE led to a significant increase in coagulation factor Von Willebrand and inflammatory marker IL1-ß compared to GFE. WISP1 and CXCL5 were upregulated in both groups. Overall, GFE showed a downregulation of inflammation and GSE led to a decrease in collagen density and increased osteoclasts. This pilot trial highlights the need for further investigation on the mechanism of action of such supplements on bone healing and oral health.