Single-cell adhesion of human osteoblasts on plasma-conditioned titanium implant surfaces in vitro.

OBJECTIVES: This study aimed to demonstrate the effect of treating titanium-implant surfaces with plasma from two different sources on wettability and initial single-cell adhesion of human osteoblasts and to investigate whether aging affects treatment outcomes. METHODS: Titanium disks with sandblasted and acid-etched (SLA) surfaces were treated with atmospheric pressure plasma (APP) and low-pressure plasma (LPP). For wetting behavior of the specimens after plasma treatment, the water contact angle was measured. The single-cell detachment force and amount of work of detachment of human osteoblasts were determined with single-cell force spectroscopy (SCFS). To evaluate the aging effect in APP-treated specimens, SCFS was conducted 10 and 60 min after treatment. RESULTS: Significantly higher hydrophilicity was observed in the APP and LPP treatment groups than in the control group, but no significant difference was observed between the APP and LPP groups. No significant difference in cell-detachment force or work of detachment was observed, and there were no significant differences according to the conditioning mechanisms and storage time. SIGNIFICANCE: Conditioning of the titanium surfaces with APP or LPP was not a significant influencing factor in the initial adhesion of the osteoblasts.

Changes in proinflammatory gene expression in human whole blood after contact with UV-conditioned implant surfaces.

OBJECTIVES: The aim of this in vitro study was to assess changes in the gene expression of proinflammatory cytokines in human whole blood after contact with titanium implant surfaces conditioned by UV light. To this end, expression levels of proinflammatory cytokines were analyzed in vitro in human whole blood. MATERIALS AND METHODS: Dental implants made of grade 4 titanium were conditioned by UV light in a UV device and submerged in human whole blood. Unconditioned implants served as controls, and blood samples without implants served as the negative control group. Sampling was performed at 1, 8, and 24 h. Changes in the expression levels of interleukin-1ß (IL1B) and tumor necrosis factor alpha (TNF) were assessed using RT-qPCR at the mRNA level. RESULTS: The gene expression of IL1B was significantly suppressed in the test group over the observation period compared to the control group during the 1-8 h after having contact between the implant surface and the blood. The gene expression of TNF was not significantly altered by UV conditioning after 1 and 8 h of observation, but both cytokine expression levels were increased significantly after 24 h. CONCLUSIONS: Differences in the gene expression of proinflammatory cytokines after insertion of UV-conditioned titanium implants can be assessed using a human whole blood test. UV-conditioned implant surfaces apparently suppress the release of IL1B in vitro. CLINICAL RELEVANCE: The results of our publication demonstrate that modulation of the early inflammatory response in human whole blood is possible by surface treatment with UV light. In particular, the suppression of IL1B expression, especially after the initial contact of blood cells, may be beneficial in the osseointegration of titanium implants by positively influence the balance between rejection and acceptance of an implant.

Effect of ultraviolet photofunctionalization of dental titanium implants on osseointegration.

OBJECTIVE: The aim of the current study was to evaluate the effect of ultraviolet (UV) photofunctionalization of dental titanium implants with exposure to the oral cavity on osseointegration in an animal model. METHODS: Forty-eight titanium implants (Camlog® Conelog® 4.3 mmx9.0 mm) were placed epicrestally into the edentulous jaws of three minipigs and implant stability was assessed by measuring the implant stability quotient (ISQ). Prior to implantation half of the implants were photofunctionalized with intense UV-light. After three months, the implants were exposed and ISQ was measured again. After six months of implant exposure, the minipigs were sacrificed and the harvested specimens were analyzed using histomorphometric, light, and fluorescence microscopy. MAIN RESULTS: Forty-two of 48 implants osseointegrated. The overall mean bone-implant contact area (BIC) was (64±22)%. No significant differences were found in BIC or ISQ value (multivariate analysis of variance (MANOVA), P>0.05) between implants with and without exposure to UV photofunctionalization. CONCLUSIONS: No significant effects were observed on osseointegration of dental titanium implants nine months after exposure of UV photofunctionalization.

Retention of zirconia on titanium in two-piece abutments with self-adhesive resin cements.

STATEMENT OF PROBLEM: Two-piece abutments consisting of a prefabricated titanium luting base and a zirconia abutment are used widely in implant restorations. Straightforward and reliable procedures for bonding titanium and zirconia are necessary for ensuring low failure rates in such restorations. PURPOSE: The purpose of this in vitro study was to evaluate the tensile load of zirconia copings on prefabricated titanium abutments using 4 different self-adhesive resin cements. MATERIAL AND METHODS: A total of 128 industrially manufactured partially yttria-stabilized zirconia ceramic copings were bonded to titanium abutments with a luting space of about 60 µm or 100 µm. The bonding surfaces were airborne-particle abraded with 50 µm alumina and cleaned ultrasonically. The zirconia copings were bonded with Panavia SA Cement Automix (SA), RelyX Unicem 2 Automix (RU), MaxCem Elite (ME), or SmartCem 2 (SC). Specimens from each cement group were randomly assigned to be stored either in distilled water (37°C) for 3 days or subjected to 37 500 thermocycles over 150 days. After debonding in tension, failure modes (adhesive or cohesive) were analyzed, and basic fuchsin dye penetration tests were performed using optical microscopy and scanning electron microscopy. Three-way ANOVA and Tukey HSD tests were used for statistical analysis (α=.05). RESULTS: Three-way ANOVA results determined that the luting resin used and the luting space had a significant effect (P≤.002), while the storage time did not have an overall effect (P>.05). The interaction between the luting resin used and storage time was significant (P<.001). After storage for 3 days, the retentive force of SA (1002 N) was highest, followed by that for RU (614 N), ME (550 N), and SC (346 N) (P≤.05); the forces for RU and ME were not significantly different (P>.05). However, after thermocycling, RU had the highest retentive force (848 N), followed by SA (646 N), ME (475 N), and SC (364 N) (P≤.05). Retentive forces for ME and SC were not significantly different (P>.05). The failure modes of the zirconia abutment surfaces were predominantly adhesive, while those of the titanium surfaces were mainly cohesive. The SA specimens showed the lowest dye penetration, followed by the RU, ME, and SC specimens. CONCLUSIONS: The greatest mean retention was found with Panavia SA Cement Automix and RelyX Unicem 2 Automix with a luting space of 60 µm when bonding zirconia copings to titanium.

Intraosseous Temperature Changes During Implant Site Preparation: In Vitro Comparison of Thermocouples and Infrared Thermography.

PURPOSE: Implant-supported dental prostheses are based on the principle of osseointegration, and the success of dental implantation depends on adequate formation of this intimate bone-to-implant contact. The application of heat during the drilling procedure leads to a rise in intraosseous temperature at the prospective implant site, which may result in various complications. The purpose of the present study was to compare the ability of thermocouples and infrared thermography to detect changes in intraosseous temperature during dental implant site preparation. MATERIALS AND METHODS: Standardized bovine costae bone blocks were used to simulate the cortical bone of the human mandible. Steel implant form drills with a diameter of 3.0 mm were used. Two types of irrigation systems were used (external cooling only and combined internal and external cooling). Drilling was performed at a constant speed (1,200 rpm). Changes in intraosseous temperature were evaluated using Type T Cu-CuNi thermocouples and an infrared thermography camera system at contact pressures of 5 and 20 N. RESULTS: Infrared thermography detected significantly greater increases in intraosseous temperature (ΔT) than thermocouples for all tested combinations of cooling system and contact pressure (P ≤ .0001). CONCLUSION: These results suggest that thermography more accurately reflects intraosseous temperature changes during implant site preparation than thermocouples.

Enhancing bone regeneration by combining mesenchymal stem cell sheets with ß-TCP/COL-I scaffolds.

The combination of bone marrow-derived mesenchymal stem cells (BMSCs) and biological scaffolds has been demonstrated to be a promising strategy for bone regeneration. However, this method does not result in satisfactory bone regeneration, because the BMSCs are dispersed in the biological scaffolds. The current study developed a new bone regeneration system, which combines synthetic porous three-dimensional scaffolds of ß-TCP/COL-I composite with cultured osteogenic sheets of BMSCs. Activity of alkaline phosphatase (ALP), a marker of bone regeneration, was assayed in vitro using enzyme-linked immunosorbent assays and quantitative real-time polymerase chain reaction. In vivo bone regeneration was assayed in male nude mice. The study samples were BMSC sheet, scaffold/scattered BMSCs, scaffold/BMSC sheet, and scaffold alone. The samples were implanted dorsally in the mice. In vitro analysis showed that ß-TCP/COL-I scaffold combined with BMSC sheets significantly upregulated both gene expression and protein levels of ALP, osteocalcin, and osteopontin. Histological and micro-computed tomography showed that the only implants that demonstrated new bone formation after 4 weeks were scaffold/BMSC sheet implants. These results underscore the crucial requirement of a synergistic effect of ß-TCP/COL-I scaffolds and BMSC sheets. This could be a promising novel strategy for bone tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2037-2045, 2018.

BMP-2 plasmid DNA-loaded chitosan films - A new strategy for bone engineering.

OBJECTIVES: Bone defects are common in every area of medicine and remain a clinical challenge. Tissue engineering has led to promising new strategies in accelerating bone repair. Bone morphogenetic proteins (BMPs) play crucial roles in bone regeneration, but are required in supra-physiological doses, which are expensive and produce severe side effects. METHODS: To address these issues, we prepared BMP-2 plasmid DNA-loaded chitosan films, and examined their effects on mouse osteoblast-like MC3T3-E1 cell morphology, proliferation, and runt-related transcription factor 2 (RUNX2) expression. In vivo testing was performed using calvarial critical-sized defects and histomorphometry in 36 Sprague-Dawley rats. Unloaded chitosan films and empty defects served as controls. RESULTS: In contrast to the controls, cells grown on BMP-2 plasmid DNA-loaded chitosan films had well established filopodia and lamellipodia, significantly higher proliferation 2, 4, and 6 days post-seeding (P ≤ 0.05), and higher nuclear RUNX2 expression. In vivo, new bone growth was significantly greater in the BMP-2 group than in the control groups at 4, 8, and 12 weeks (P ≤ 0.01). CONCLUSIONS: Based on our study findings, BMP-2 plasmid DNA-loaded chitosan films provide an effective strategy for GBR, combining cellular compatibility with biocapability in vivo.

Impact of Cleaning Procedures on Adhesion of Living Cells to Three Abutment Materials.

PURPOSE: To test the adhesion properties of live gingival fibroblasts to three different implant abutment materials after five different cleaning procedures. MATERIALS AND METHODS: Highly polished discs of lithium disilicate (LS), zirconium dioxide (Zr), and titanium alloy (Ti) were fabricated. The specimens were cleaned by one of five different methods: steam (S), argon plasma (AP), ultrasound and disinfection (UD), ultrasound and sterilization in an autoclave (UA), or photofunctionalization with high-intensity ultraviolet light (PF). Cell detachment force (adhesion) was measured by single-cell force spectroscopy, which is a method to quantify cell adhesion at the single cell level. Data were statistically analyzed using parametric tests (analysis of variance [ANOVA], t tests). RESULTS: Cell detachment forces in the low nN regime were recorded in all experiments. Significant differences in cell adhesion on the different materials were found as a function of the cleaning method (P ≤ .0001). For LS abutments, no significant differences between the cleaning methods could be found (P > .05). For Zr specimens, the AP method showed the highest cell detachment forces, followed by UD, PF, S, and UA (S/UD, S/UA, S/PF, AP/UD, and UD/PF were not significantly different from each other). For Ti abutments, UD showed the highest cell detachment forces, followed by S, AP, and UA/PF (S/UD, S/UA, S/PF, AP/U, and UA/PF were not significantly different from each other). CONCLUSION: All cleaning methods provided comparable cell detachment forces for LS abutments. AP/PF or ultrasonic cleaning were the most suitable methods for strong cell adhesion on Zr. UD provided the best cell adhesion for Ti.

In vitro remineralization of hybrid layers using biomimetic analogs.

Resin-dentin bond degradation is a major cause of restoration failures. The major aim of the current study was to evaluate the impact of a remineralization medium on collagen matrices of hybrid layers of three different adhesive resins using nanotechnology methods. Coronal dentin surfaces were prepared from freshly extracted premolars and bonded to composite resin using three adhesive resins (FluoroBond II, Xeno-III-Bond, and iBond). From each tooth, two central slabs were selected for the study. The slabs used as controls were immersed in a simulated body fluid (SBF). The experimental slabs were immersed in a Portland cement-based remineralization medium that contained two biomimetic analogs (biomineralization medium (BRM)). Eight slabs per group were retrieved after 1, 2, 3, and 4 months, respectively and immersed in Rhodamine B for 24 h. Confocal laser scanning microscopy was used to evaluate the permeability of hybrid layers to Rhodamine B. Data were analyzed by analysis of variance (ANOVA) and Tukey's honest significant difference (HSD) tests. After four months, all BRM specimens exhibited a significantly smaller fluorescent area than SBF specimens, indicating a remineralization of the hybrid layer (P≤0.05). A clinically applicable biomimetic remineralization delivery system could potentially slow down bond degradation.

Influence of Four Different Abutment Materials and the Adhesive Joint of Two-Piece Abutments on Cervical Implant Bone and Soft Tissue.

PURPOSE: The main aim of this study was to evaluate the influence of four different abutment materials and the adhesive joint of two-piece abutments on the cervical implant bone and soft tissue. MATERIALS AND METHODS: Sixty-four titanium implants (Camlog Conelog; 4.3 ± 9 mm) were placed bone level into the edentulous arches of four minipigs. Four different types of abutments were placed at implant exposure: zirconium dioxide, lithium disilicate, and titanium bonded to a titanium luting base with resin cement; one-piece titanium abutments served as the control. The animals were sacrificed 6 months after implant exposure, and the bone-to-implant contact (BIC) area, sulcus depth, the length of the junctional epithelium and the connective tissue, the biologic width, and first cervical BIC-implant shoulder distance were measured using histomorphometry and light and fluorescence microscopy. RESULTS: Overall, 14 implants were lost (22%). At exposure, the implant shoulder-bone distance was 0.6 ± 0.7 mm. Six months later, the bone loss was 2.1 ± 1.2 mm measured histomorphometrically. There was a significant difference between the two measurements (P ≤ .0001). No significant influence could be found between any of the abutment materials with regard to bone loss or soft tissue anatomy (P > .05), with the exception of zirconium dioxide and onepiece titanium abutments when measuring the length of the junctional epithelium (P ≤ .01). The maxilla provided significantly more soft tissue and less bone loss compared with the mandible (P ≤ .02). CONCLUSION: All tested abutment materials and techniques seem to be comparable with regard to soft tissue properties and the cervical bone level.

Adhesion of living cells to abutment materials, dentin, and adhesive luting cement with different surface qualities.

OBJECTIVE: We tested the adhesion properties of living gingival fibroblasts on three different implant abutment materials, adhesive resin used to bond bi-partite abutments, and human dentin. METHODS: Discs of lithium disilicate (LS), zirconium dioxide (Zr), adhesive resin cement (AR), titanium (Ti), and human dentin (HD) were fabricated with three different levels of surface roughness (rough, machined, and polished). Ra and Rz, water contact angle, and cell detachment forces were measured. Cell detachment force was measured for single cells using single-cell force spectroscopy. Data were statistically analyzed using parametric tests (ANOVA, MANOVA, Bonferroni post-hoc tests). RESULTS: Surface roughness significantly influenced the water contact angle for all materials (P≤0.05). Overall, HD showed the lowest contact angle, followed by LS, Ti, Zr, and AR (P≤0.05). Comparison of cell detachment forces between materials with rough and machined surfaces revealed no significant differences (P>0.05), with the exception of Zr compared to HD with rough surfaces (P=0.006). For polished surfaces, HD showed the highest detachment force (P≤0.0001), followed by Ti, AR, and Zr, which did not significantly differ from each other (P>0.05) and LS; Ti/AR was significantly different from LS (P≤0.05). Except for HD, where polished surfaces exhibited the highest cell detachment force (P≤0.002), most machined surfaces showed higher cell detachment forces than polished or rough surfaces. SIGNIFICANCE: Implant abutments should ideally be provided with a machined like surface roughness for best cell adhesion.

Can one-wall bone defects be augmented with xenogenic bone grafting material alone?

OBJECTIVES: The main aim of this study was to evaluate the impact of xenogenic bovine bone grafting material particle size, addition of harvested autogenic bone as well as the influence of a periosteum on growth of newly formed bone, bone marrow, residual bone grafting material and connective tissue of one-wall defects. METHODS: Overall 32 augmentation sites were placed on the frontal skull of four minipigs and covered with titanium pin immobilized absorbable porcine membranes. After a 6 month healing period the harvested specimens were analyzed using light- and fluorescence microscopy. RESULTS: In the augmented areas 47%-57% bone, 14%-34% bone marrow, 10%-20% residual xenogenic bone grafting material and 4.5%-10% connective tissue were found. Admixture of autogenic bone resulted in statistically significantly more newly formed bone, more bone marrow, less residual xenogenic bone grafting material and less connective tissue (P ≤ 0.03). CONCLUSIONS: While augmenting one-wall defects seems to be possible with xenogenic grafting material and absorbable membranes alone, the addition of autogenic bone seems to benefit the augmentation site.

Is There a Correlation Between Tensile Strength and Retrievability of Cemented Implant-Retained Crowns Using Artificial Aging?

PURPOSE: The main goal of this in-vitro study was to evaluate whether tensile strength and retrievability of cemented implant-retained crowns correlate when using artificial aging. MATERIALS AND METHODS: A total of 128 crowns were fabricated from a cobalt-chromium alloy for 128 tapered titanium abutments (6 degrees taper, 4.3 mm diameter, 4 mm length, Camlog). The crowns were cemented with glass-ionomer (Ketac Cem, 3M) or resin cements (Multilink Implant, Telio CS Cem [Ivoclar Vivadent], Retrieve [Parkell]). Multilink Implant was used without priming. The experimental groups were subjected to either 37,500 thermal cycles between 5°C and 55°C, 1,200,000 chewing cycles, or a combination of both. Control groups were stored for 10 days in deionized water. The crowns were removed with a universal testing machine or a clinically used removal device (Coronaflex, KaVo). Data were statistically analyzed using nonparametrical tests. RESULTS: Retention values were recorded between 31 N and 362 N. Telio CS Cem showed the lowest retention values, followed by Retrieve, Ketac Cem, and Multilink Implant (P≤.0001). The number of removal attempts with the Coronaflex were not significantly different between the cements (P>.05). Thermal cycling and chewing simulation significantly influenced the retrieval of Retrieve Telio CS Cem, and Ketac Cem specimens (P≤.05). Only for Multilink Implant and Telio CS Cem correlations between removal with the universal testing machine and the Coronaflex could be revealed (P≤.0001). CONCLUSIONS: Ketac Cem and Multilink Implant (without silane) can be used for a semipermanent cementation. Retrieve and Telio CS Cem are recommendable for a temporary cementation.

Retention of bonded titanium copings fixed to implant abutments.

STATEMENT OF PROBLEM: Conical abutments can be laser welded to the abutment base to compensate for differing implant axes. As laser welding requires expensive equipment, alternative methods for bonding the conical abutment part with the abutment base should be considered. PURPOSE: The purpose of this in vitro study was to evaluate the retention of Ti-6Al-7Nb copings bonded adhesively to Ti-6Al-7Nb abutments and to compare it with the stability achieved by laser welding. MATERIAL AND METHODS: A total of 104 two-part Ti-6Al-7Nb specimens were prepared and divided into 13 groups with 8 specimens each. In this 2-part study, 3 luting resins (Panavia F 2.0 [PF]; Multilink Automix [MA]; Superbond C&B [SB]) were used with or without metal priming (PR). The laser welding group (LW) served as the control. After storage for 1 or 150 days (150 days with thermal cycling [TC]), push-out retention and welded joint stability were tested. The data were analyzed with ANOVA and the Tukey HSD multiple comparison tests. RESULTS: The choice of resin, thermal cycling, and metal priming had a significant effect on resin push-out retention. LW provided the strongest retention, followed by PF, MA, and SB. For PF and SB, TC decreased retention. PR did not lead to higher retention but provided better bonding stability when TC was applied. CONCLUSIONS: The retention values suggest that considering the maximum mastication forces, resin bonding is an appropriate substitute for the laser welding method.

Wear, microleakage and plastic deformation of an implant-supported chair-side bar system.

PURPOSE: This in-vitro study was designed to evaluate retention forces, microleakage and plastic deformation of a prefabricated 2-implant bar attachment system (SFI-Bar, Cendres+Métaux, Switzerland). MATERIALS AND METHODS: Two SFI implant-adapters were torqued with 35 Ncm into two implant analogues. Before the tube bars were finally sealed, the inner cavity of the tube bar was filled with liquid red dye to evaluate microleakage. As tube bar sealing agents three different materials were used (AGC Cem (AGC, resin based), Cervitec Plus (CP; varnish) and Gapseal (GS; silicone based). Four groups with eight specimens each were tested (GS, GS+AGC, AGC, CP). For cyclic loading, the attachment system was assembled parallel to the female counterparts in a chewing simulator. The mean retention forces of the initial and final ten cycles were statistically evaluated (ANOVA, α≤.05). RESULTS: All groups showed a significant loss of retention forces. Their means differed between 30-39 N initially and 22-28 N after 50,000 loading cycles. No significant statistical differences could be found between the groups at the beginning (P=.224), at the end (P=.257) or between the loss of retention forces (P=.288). Microleakage occurred initially only in some groups but after 10,000 loading cycles all groups exhibited microleakage. CONCLUSION: Long-term retention forces of the SFI-Bar remained above 20 N which can be considered clinically sufficient. The sealing agents in this study are not suitable to prevent microleakage.

Influence of dental education on esthetic perception.

AIM: One of the most challenging tasks in daily practice when it comes to defining treatment goals and how to attain them is the communication with the patient and the self-reflection of the treating dentist. Failures due to mis-communication are common, especially in esthetic dentistry. The purpose of this study was to evaluate the influence of dental education on students' and dentists' judgment of patients' dental appearance. MATERIALS AND METHODS: Based on internationally accepted guidelines about dental esthetics, a questionnaire was developed to measure "dental appearance" (QDA). Eleven items defined a QDA score (0 = "absolutely dissatisfied", 100 = "absolutely satisfied"). The QDA was completed by 29 patients (21 women, 8 men) before and after a complete oral rehabilitation, including restoration of the anterior teeth. Overall, 95 students (1st, 5th, and 10th Semester) and 30 dentists evaluated the patients' esthetics before and after rehabilitation on a visual analog scale (VAS; 0 = "absolutely unesthetic", 100 = "absolutely esthetic"). RESULTS: Students and dentists alike judged a significant esthetic improvement after treatment (P ≤ 0.0001). Significant differences could be found when comparing the students' and dentists' judgment and the patients' self-evaluation (P ≤ 0.05). CONCLUSION: Since it seems that students judge dental appearance differently from patients' self-assessment, teaching esthetic rules at university should incorporate the aspect of patient feedback in order to avoid misconceptions.

Perception of dental esthetics: influence of restoration type, symmetry, and color in four different countries.

In this study, the influence of restoration type, symmetry, and color on the perception of dental appearance was evaluated. An esthetic questionnaire was completed by 29 patients before and after esthetic rehabilitation. In addition, 94 dentists from four countries (Germany, the United Kingdom [UK], China, and Switzerland) evaluated the influence of the above factors using before-and-after rehabilitation pictures. The most invasive treatment was recommended by Chinese dentists, while German, Swiss, and UK dentists recommended comparable treatment options. As for restorative symmetry, restoration type, and color, significant differences could be found among and within the dentists of the four countries (P ± .05).

3D-tracking the regenerative potential of the mandible with micro-CTs.

PURPOSE: The treatment of large bone defects is a challenging problem especially when the mandible is affected. Bone healing is dependent on the defect size and the integrity of periosteum. So far, these both aspects have not been investigated separately. The aim of this study was to evaluate the healing potential of the mandibular bone with the help of three-dimensional micro-computed tomography (CT). METHODS: The angle of the mandible was exposed in 15 Wistar rats. A 3-mm core of bone was removed with a trephine. The local periosteum next to the defect was excised. Animals were randomized in five groups, which were ended 5, 10, 15, 28 and 56 days after operation. The mandible was excised and underwent micro-CT. For statistical evaluation, t-test statistics and regression analysis were applied. RESULTS: Characteristics of the defects began to change on the tenth postoperative day. Fifteen days until 4 weeks after intervention new mineralization processes could be observed. New bone grew from the borders into the defect. In the 2D study, bone apposition changed significantly from the beginning to week 8 (0.08 to 0.74 mm) as well as the 3D bone gain (0.05 % to 29.67 %) in t-test statistical evaluation. For development of the bone volume inside the defect linear as well as exponential regression analysis revealed a statistically significant connection. CONCLUSIONS: This study quantified the amount of newly grown bone during osseous regeneration. We could show that the mandible itself provides regenerative capacity without any intact periosteum.

Perception of dental esthetics in different cultures.

PURPOSE: The purpose of this study was to compare patients' and dentists' perception of dental appearance. MATERIALS AND METHODS: Based on internationally accepted guidelines about dental esthetics, a questionnaire was developed to measure "dental appearance" (QDA). Eleven items defined a QDA score (0 = "absolutely dissatisfied" to 100 = "absolutely satisfied"). The QDA was completed by 29 patients (21 women, 8 men) before and after a complete oral rehabilitation that included restoration of the maxillary anterior teeth. Overall, 94 dentists from four countries (Germany, the United Kingdom, China, and Switzerland) evaluated the esthetics before and after rehabilitation on a visual analog scale (VAS: 0 = "absolutely unesthetic" to 100 = "absolutely esthetic"). RESULTS: Patients and dentists of all countries found a significant esthetic improvement after treatment (P ≤ .0001). Significant differences could be found when comparing the evaluation of the dentists from the various countries among one another and with the patients' self-evaluation (P ≤ .05). With the exception of the professional rating of the initial situation, no gender-related differences could be found in any of the test groups. CONCLUSIONS: In daily practice, it seems of utmost importance for dentists to incorporate the patients' feedback in order to avoid esthetic treatment failures.

Influence of casein phosphopeptide-amorphous calcium phosphate application, smear layer removal, and storage time on resin-dentin bonding.

The aim of this study is to evaluate the influence of Tooth Mousse (TM) application, smear layer removal, and storage time on resin-dentin microtensile bond strength (µTBS). Dentin specimens were divided into two groups: (1) smear layer covered; (2) smear layer removed using 15% EDTA for 90 s. In each group, half the specimens were treated once with TM for 60 min. After bonding procedures using a two-step self-etching adhesive (Clearfil SE Bond (CSE); Kuraray Medical, Tokyo, Japan), an all-in-one adhesive (G-Bond (GB); GC Corp, Tokyo, Japan), and a total-etch adhesive (Adper Single Bond 2 (SB); 3M ESPE, St. Paul, MN, USA), the specimens were stored for 3 d or 6 months in deionized water at 37 °C, and µTBS was tested and analyzed. With the exception of SB (no TM application) and GB, the µTBS was significantly increased for CSE and SB using EDTA pre-conditioning and 3 d of storage (P≤0.001). Bond strength of GB decreased significantly when using EDTA (3 d storage, P<0.05). TM application only increased the µTBS of GB (no EDTA) and SB (with EDTA) after 3 d (P≤0.02). Comparing the adhesives after 3 d of storage, CSE exhibited the greatest µTBS values followed by GB and SB (P≤0.02). The factors of adhesive, EDTA, and TM did not show any significant impact on µTBS when specimens were stored for 6 months (P>0.05). The additional application of TM and EDTA for cavity preparation seems only to have a short-term effect, and no influence on µTBS of dentin bonds after a period of 6 months.