Clinical and microbiological effects of different restorative materials on the periodontal tissues adjacent to subgingival class V restorations. 1-year results

Alternative Direct Restorative Materials for Dental Amalgam: A Concise Review Based on an FDI Policy Statement

Dental restorative procedures remain a cornerstone of dental practice, and for many decades, dental amalgam was the most frequently employed material. However, its use is declining, mainly driven by its poor aesthetics and by the development of tooth-coloured adhesive materials. Furthermore, the Minamata Convention agreed on a phase-down on the use of dental amalgam. This concise review is based on a FDI Policy Statement which provides guidance on the selection of direct restorative materials as alternatives to amalgam. The Policy Statement was informed by current literature, identified mainly from PubMed and the internet. Ultimately, dental, oral, and patient factors should be considered when choosing the best material for each individual case. Dental factors include the dentition, tooth type, and cavity class and extension; oral aspects comprise caries risk profiles and related risk factors; and patient-related aspects include systemic risks/medical conditions such as allergies towards certain materials as well as compliance. Special protective measures (eg, a no-touch technique, blue light protection) are required when handling resin-based materials, and copious water spray is recommended when adjusting or removing restorative materials. Cost and reimbursement policies may need to be considered when amalgam alternatives are used, and the material recommendation requires the informed consent of the patient. There is no single material which can replace amalgam in all applications; different materials are needed for different situations. The policy statement recommends using a patient-centred rather than purely a material-centred approach. Further research is needed to improve overall material properties, the clinical performance, the impact on the environment, and cost-effectiveness of all alternative materials.

Agenesis of the maxillary permanent lateral incisors with the deciduous retained: Conservative and biomimetic approach using the BAIR technique

OBJECTIVE

Agenesis of the maxillary permanent lateral incisors is a condition that requires treatment aimed at improving the esthetics, even at an early age. However, traditional therapeutic protocols are long, invasive and have limitations and contraindications imposed by the age of the patient.

CLINICAL CONSIDERATIONS

Recent developments in restorative dentistry have provided a new approach to this clinical situation, in particular when the deciduous laterals are retained. We report two cases regarding the management of missing lateral incisors using Biologically Active Intrasulcular Restoration (BAIR) technique. The BAIR technique allows us to transform the shape of the deciduous lateral incisor into the permanent, acting both on the dental morphology and proportions, and on the appearance of the soft tissues and the gingival parables.

CONCLUSIONS

The BAIR technique is a valid approach to cases of agenesis of the maxillary permanent lateral incisors, when the deciduous are retained. It does not require any preparation of the dental tissues, is reversible and minimally invasive. It is applicable to patients of all ages, and results are obtained in a single appointment.

CLINICAL SIGNIFICANCE

The BAIR technique allows a biomimetic conservative approach for the rehabilitation of congenitally missing permanent lateral incisors, when the deciduous are retained. It is a non-invasive protocol and effective in successfully restoring esthetics.

Effect of a 3-second Off-label Exposure on the Depth of Cure of Eight Resin-based Composites

OBJECTIVES

This study evaluated the depth of cure (DoC) of eight resin-based composites (RBCs) photocured using one multipeak light-curing unit (LCU) on the standard output setting for the manufacturer's RBC recommended exposure time and at a higher irradiance for 3 seconds.

METHODS

Three conventional RBCs: Tetric EvoCeram (Evo), Tetric N-Ceram (Cer), Tetric Prime (Pri); and five bulk-fill: Tetric N-Ceram Bulk Fill (CerBF), Opus Bulk Fill APS (OpusBF), Opus Bulk Fill Flow APS (OpusF), Tetric PowerFill (PFill) and Tetric PowerFlow (PFlow) were examined. Only PFill and PFlow are formulated to be photocured in 3 seconds. The RBCs were packed into a metal mold and photocured using a Bluephase PowerCure LCU for the RBC manufacturer's recommended exposure time on the standard mode and using the 3-second high irradiance mode. After photocuring, the specimens were immersed in a solvent for 1 hour. The length of the remaining RBC was measured and divided by 2. Data were analyzed using two-way analysis of variance (ANOVA) followed by the Tukey post hoc multiple comparison test (α=0.05).

RESULTS

There was no significant difference in the DoC values for PFill and PFlow when photocured using the 3-second high irradiance protocol compared to the lower irradiance standard mode protocol. All other RBCs had significantly lower DoC values (p<0.001) when photocured off-label using the 3-second high irradiance mode.

CONCLUSION

Of the eight RBCs tested, only PFill and PFlow achieved the same DoC when the high irradiance 3-second curing method was used compared to when their longer lower irradiance protocol was used.

Acellular dermal matrix for the treatment of multiple gingival recession defects associated with carious and previously restored cervical lesions: A case report with 10 years of follow-up

BACKGROUND

Limited evidence exists on the outcome of the modified coronally advanced tunnel (MCAT) with acellular dermal matrix (ADM) for the treatment of gingival recession defects (GRD) especially when complicated by restored cervical lesions. Therefore, the aim of this case report was to assess the short- and long-term clinical outcomes of maxillary Type 1 recession defects (RT1) associated with restored cervical lesions treated with MCAT with ADM.

METHODS AND RESULTS

A 43-year-old female patient, presented with multiple adjacent RT1 recessions in the left maxilla, previously treated with overhanging cervical resin restorations. The case was approached with a careful evaluation of the diagnostic determinants of root coverage, removal of the aberrant resin restorations, treatment with MCAT with ADM, and periodical evaluation over a follow-up of 10 years. The treatment was followed by complete root coverage, improvement of gingival phenotype, and perfect root coverage esthetic score. Outcomes were periodically assessed and were maintained over 10 years of follow-up.

CONCLUSION

MCAT with ADM is an effective technique for the treatment of multiple GRD complicated by cervical restorations. Complete root coverage and excellent esthetic outcomes were obtained and maintained in the long term.

The effect of dental material type and masticatory forces on periodontitis-derived subgingival microbiomes

Restorative dental materials can frequently extend below the gingival margin, serving as a potential haven for microbial colonization, and altering the local oral microbiome to ignite infection. However, the contribution of dental materials on driving changes of the composition of the subgingival microbiome is under-investigated. This study evaluated the microbiome-modulating properties of three biomaterials, namely resin dental composites (COM), antimicrobial piezoelectric composites (BTO), and hydroxyapatite (HA), using an optimized in vitro subgingival microbiome model derived from patients with periodontal disease. Dental materials were subjected to static or cyclic loading (mastication forces) during biofilm growth. Microbiome composition was assessed by 16S rRNA gene sequencing. Dysbiosis was measured in terms of subgingival microbial dysbiosis index (SMDI). Biomaterials subjected to cyclic masticatory loads were associated with enhanced biofilm viability except on the antibacterial composite. Biomaterials held static were associated with increased biofilm biomass, especially on HA surfaces. Overall, the microbiome richness (Chao index) was similar for all the biomaterials and loading conditions. However, the microbiome diversity (Shannon index) for the HA beams was significantly different than both composites. In addition, beta diversity analysis revealed significant differences between composites and HA biomaterials, and between both loading conditions (static and cyclic). Under static conditions, microbiomes formed over HA surfaces resulted in increased dysbiosis compared to composites through the enrichment of periopathogens, including Porphyromonas gingivalis, Porphyromonas endodontalis, and Fretibacterium spp., and depletion of commensals such as Granulicatella and Streptococcus spp. Interestingly, cyclic loading reversed the dysbiosis of microbiomes formed over HA (depletion of periopathogenes) but increased the dysbiosis of microbiomes formed over composites (enrichment of Porphyromonas gingivalis and Fusobacterim nucleatum). Comparison of species formed on both composites (control and antibacterial) showed some differences. Commercial composites enriched Selenomonas spp. and depleted Campylobacter concisus. Piezoelectric composites effectively controlled the microbiome viability without significantly impacting the species abundance. Findings of this work open new understandings of the effects of different biomaterials on the modulation of oral biofilms and the relationship with oral subgingival infections.

Evaluation of a novel restorative protocol to treat non-carious cervical lesion associated with gingival recession: a 2-year follow-up randomized clinical trial

OBJECTIVE

To compare 2 different resin composites and 2 adhesive systems used in a new restorative protocol (partial restoration) to treat non-carious cervical lesions associated with gingival recession type 1 (RT1).

MATERIAL AND METHODS

Eighty combined defects (CDs) were treated with a partial restoration and periodontal plastic surgery for root coverage. The CDs were randomly assigned to one of the following groups: NP + TE (n = 20), nanofilled composite and 2-step total-etch adhesive system; NP + UA (n = 20), nanofilled composite and universal adhesive system; MH + TE (n = 20), microhybrid composite and 2-step total-etch adhesive; MH + UA (n = 20), microhybrid composite and universal adhesive. Restorations were assessed using the United States Public Health Service (USPHS) criteria at 1 week (baseline) and 6, 12, and 24 months. Survival rate, periodontal parameters, dentin hypersensitivity (DH), and aesthetics were also evaluated.

RESULTS

After 24 months, only the MH + TE group did not lose any restoration, with no significant differences between groups. For surface roughness parameter, MH presented 83.3% of the restorations scoring Bravo, whereas NP presented 48.5% of the restorations scoring Bravo. All groups presented restorations with marginal discoloration. All periodontal parameters behaved similarly, regardless of the restorative material. All groups presented significant reductions of dentin hypersensitivity and improved aesthetic perceptions (p < 0.05).

CONCLUSION

Both resin composites and adhesives tested can be combined for partial restorations to treat CDs.

CLINICAL RELEVANCE

This new restorative-surgical protocol to treat CDs presents satisfactory outcomes. The partial restorations can be successfully executed with both combinations of adhesives and resin composites evaluated in this investigation. TRN : ClinicalTrial.gov: NCT03215615; registration date July 12, 2017.

Intra-Oral Photograph Analysis for Gingivitis Screening in Orthodontic Patients

This study aimed to confirm the presence of gingival inflammation through image analysis of the papillary gingiva using intra-oral photographs (IOPs) before and after orthodontic treatment and to confirm the possibility of using gingival image analysis for gingivitis screening. Five hundred and eighty-eight (n  =  588) gingival sites from the IOPs of 98 patients were included. Twenty-five participants who had completed their orthodontic treatments and were aged between 20 and 37 were included. Six points on the papillary gingiva were selected in the maxillary and mandibular anterior incisors. The red/green (R/G) ratio values were obtained for the selected gingival images and the modified gingival index (GI) was compared. The change in the R/G values during the orthodontic treatment period appeared in the order of before orthodontic treatment (BO), mid-point of orthodontic treatment (MO), three-quarters of the way through orthodontic treatment (TO), and immediately after debonding (IDO), confirming that it was similar to the change in the GI. The R/G value of the gingiva in the image correlated with the GI. Therefore, it could be used as a major index for gingivitis diagnosis using images.

Influence of the Scalpel Finishing Technique on Marginal Gap Formation in Class II Resin Composite Restorations

OBJECTIVES

Modern adhesives and composites allow the restoration of deep defects. In such cases, the matrix technique is particularly challenging, and excess composite is a common problem. Removing such overhangs with a scalpel has already been described as a substance preserving or selective finishing technique. Clinically, restoration margins may appear as a white line after scalpel finishing, and it is unclear whether this line represents a marginal gap and/or whether scalpel finishing promotes marginal gap formation. Therefore, the aim of this study was to investigate the influence of scalpel finishing of deep Class II composite restorations on marginal gap formation.

METHODS AND MATERIALS

Standardized mesioocclusal-distal (MOD) cavities were prepared and restored in 60 human molars randomly divided into six finishing protocol groups: G1, scalpels (SC); G2, oscillating files (OF); G3, finishing strips (FS); G4, scalpels and finishing strips (SC+FS); G5, scalpels and polishing discs (SC+PD); G6, polishing discs alone (PD, controls). The groups were additionally assigned to finishing and polishing in a phantom head (groups 1-4) or hand-held setting (groups 5-6) to simulate clinical and in-vitro research conditions, respectively. After restoration, artificial aging was performed by thermocycling (5-55°C, 2500 cycles) and mechanical loading (50 newtons (N) with 500,000 cycles) prior to scanning electron microscopy analysis of proximal restoration margin quality on the mesial and distal surfaces (n=120) of each tooth. Outcomes (perfect margin, marginal gap, overhang, marginal fracture) were statistically analyzed by t-test, Mann-Whitney U test, single-factor analysis of variance, post-hoc t-test, Kruskal-Wallis test and Dunn-Bonferroni correction for multiple group comparisons. Cohen's effect size d(Cohen) was calculated to show the strength of the relationship between variables.

RESULTS

Overall, marginal quality was significantly better in the hand-held setting (SC+PD and PD) than the phantom head setting (SC, OF, FS, SC+FS). The best marginal quality was achieved with oscillating files in the phantom head setting and with scalpels plus polishing discs in the hand-held setting. Marginal gaps occurred significantly more often with scalpels, but the proportion of gaps was very low and clinically insignificant. Finishing strips were the least effective instruments for removing overhangs but performed better in combination with scalpels.

CONCLUSIONS

Scalpel finishing can effectively and gently remove overhangs from enamel. However, blades should be used with caution as they can cut the dentin and cementum. Scalpel finishing does not lead to a clinically relevant increase in marginal gaps, but should be followed by polishing, whenever possible, to eliminate any marginal fractures that might be present.

Deep Margin Elevation: Current Concepts and Clinical Considerations: A Review

Dietschi and Spreafico first proposed deep margin elevation (DME) in 1998 to address the multiple clinical problems associated with sub-gingival margins, where sub-gingival margins will be repositioned coronally using composite resin restorations. Given that dentistry is directing towards conservatism, its use is currently trending. Materials and Methods: a search was performed through PubMed, Scopus, and Google Scholar search engines to obtain relevant articles with no time restriction. Results: With biological width taken into consideration, well-defined and polished sub-gingival restorations are compatible with periodontal health. Marginal integrity in the DME technique seems to be affected by the type of adhesive, restoration, and incremental layering of the restoration. Regarding fracture resistance, DME has no significant effects. Conclusion: The DME technique seems to be a minimally invasive alternative to surgical crown lengthening (SCL) and orthodontic extrusion (OE) with respect to biological width. Well-controlled clinical trials are limited in this field; further long-term follow-up studies emphasizing the periodontal outcomes and prevention of complications are needed.

Intrasulcular Restorations of Anterior Teeth According to the BAIR Technique: Evaluation of Periodontal Parameters

Some clinical situations, such as the closure of pronounced diastemas, and the transformation of malformed, small, or peg-shaped teeth, require a rebalancing of dental proportions accompanied by a modification of the gingival contour. A traditional treatment plan can include surgical, prosthetic, and/or orthodontic treatments. In some cases, it can be considered too invasive, and not all patients are willing to undertake long therapies. To overcome these limitations, a possible solution could be the application of the Biologically Active Intrasulcular Restoration (BAIR) technique, which allows us to modify the natural emergence tooth profile using simple intrasulcular direct restorations. The aims of this paper are to investigate possible effects on gingival health, and to assess the patient satisfaction about the aesthetic intervention performed. Periodontal data were collected, and patient satisfaction was registered using the VAS questionnaire. All sites healed without complications, no adverse events were registered or reported by the patients, and no signs of periodontal morbidity were visible. The results show that the patients evaluated the final aesthetics in a positive way, and they perceived a good condition of periodontal health as well. The intervention is felt as almost painless, and patients do not report significant post-operative distress. In conclusion, the BAIR technique can provide a valid therapeutic alternative for patients for whom traditional treatments are not indicated. It is a minimally invasive intervention where both the operating times and the biologic and economic costs are reduced.

Restorative Materials Exposed to Acid Challenge: Influence of Temperature on In Vitro Weight Loss

Consumption of acidic beverages and foods could provoke erosive damage, both for teeth and for restorative materials. Temperatures of consumption could influence the erosive effects of these products. The aim of this in vitro study is to assess the influence of an acidic challenge on the weight loss of different restorative materials. Resin composites and glass-ionomer cements (GIC) were tested. The medium of storage was Coca-Cola (Coca-Cola, Coca-Cola Company, Milano, Italy) at two different temperatures, 4 and 37 °C, respectively for Group A and Group B. For each group, nine specimens were prepared for each material tested. After 7 days, weight was assessed for each sample, and the percentage weight loss was calculated. For all the resin composites (Groups 1−13), no significant weight losses were noticed. (<1%). Conversely, GICs (Groups 14 and 15) showed significant weight loss during the acidic challenge, which was reduced in the case of these materials that included a protective layer applied above. Significant differences were registered with intra-group analysis; weight loss for specimens immersed in Coca Cola at 37 °C was significantly higher for almost all materials tested when compared to specimens exposed to a cooler medium. In conclusion, all the resin composites showed reliable behaviour when exposed to acidic erosion, whereas glass-ionomer cements generally tended to solubilize.

Application of Texture and Fractal Dimension Analysis to Evaluate Subgingival Cement Surfaces in Terms of Biocompatibility

Biocompatibility is defined as “the ability of a biomaterial, prosthesis, or medical device to perform with an appropriate host response in a specific application”. Biocompatibility is especially important for restorative dentists as they use materials that remain in close contact with living tissues for a long time. The research material involves six types of cement used frequently in the subgingival region: Ketac Fil Plus (3M ESPE, Germany), Riva Self Cure (SDI, Australia) (Glass Ionomer Cements), Breeze (Pentron Clinical, USA) (Resin-based Cement), Adhesor Carbofine (Pentron, Czech Republic), Harvard Polycarboxylat Cement (Harvard Dental, Great Britain) (Zinc polycarboxylate types of cement) and Agatos S (Chema-Elektromet, Poland) (Zinc Phosphate Cement). Texture and fractal dimension analysis was applied. An evaluation of cytotoxicity and cell adhesion was carried out. The fractal dimension of Breeze (Pentron Clinical, USA) differed in each of the tested types of cement. Adhesor Carbofine (Pentron, Czech Republic) cytotoxicity was rated 4 on a 0–4 scale. The Ketac Fil Plus (3M ESPE, Germany) and Riva Self Cure (SDI, Australia) cements showed the most favorable conditions for the adhesion of fibroblasts, despite statistically significant differences in the fractal dimension of their surfaces.

Impact of interproximal composite restorations on periodontal tissue health: Clinical and cytokine profiles from a pre-post quasi-experimental study

BACKGROUND

The aim of this study is to clinically and molecularly evaluate the effect of an interproximal iuxta/subgingival direct composite restoration on periodontal tissue healing.

METHODS

Individuals in need of a posterior iuxta/subgingival interproximal restoration were consecutively enrolled. After enrollment, a test (site with tooth decay) and a control site (intact contralateral tooth) were identified. After a periodontal examination (probing depth [PD], clinical attachment level, recession, plaque, and bleeding on probing [BOP]) and a sampling of gingival crevicular fluid, the composite restoration was performed (T₀ ). Clinical and molecular assessments were repeated at 3 (T₃ ), 6 (T₆ ), and 12 (T₁₂ ) months after the restoration. Intragroup pre-post comparisons for quantitative variables were performed either through one-way ANOVA or Kruskal-Wallis test. A multivariate linear regression analysis was then modeled. With α = 0.05, a power of 80% will be reached with the inclusion of 41 individuals.

RESULTS

Biometric parameters demonstrated an increased mean PD (ΔPDT₀ -T₁₂ = -0.83 mm; P = 0.001) and loss of attachment (AL) (ΔCALT₀ -T₁₂ = -0.91 mm; P = 0.005) in the test site at 12 months. Accordingly, in the final multivariate regression model the radiographic distance between the bone crest and the restorative margin at baseline accounted for the dependent variable "attachment loss (AL)" (ΔCALT₀ -T₁₂ ) (P <0.05).

CONCLUSIONS

Iuxta/subgingival interproximal restorative margins jeopardized clinically and molecularly the periodontal tissue healing at least up to 1 year of follow-up.

Cytotoxicity of Different Composite Resins on Human Gingival Fibroblast Cell Lines

The aim of the present study was to evaluate and compare the cytotoxic effects of eight composite resins on immortalized human gingival fibroblasts. Composite resins were eluted in cell culture medium for 48 or 72 h at 37 °C. Immortalized human gingival fibroblast-1 (HGF-1) cell lines were seeded in 96-well (1 × 10⁴) plates and incubated for 24 h at 37 °C with the obtained extraction medium. The percentage of viable cells in each well (MTT test) was calculated relative to control cells, which were set to 100%. Data observed were not normally distributed, and nonparametric statistical methods were used for statistical analysis. The Wilcoxon test was used for intragroup comparison, and the Kruskal–Wallis test was used for intergroup multiple comparisons. Significance value was set as p < 0.05. All materials tested showed cytotoxic effects on gingival fibroblasts, recordable as noncytotoxic, mildly cytotoxic or severely cytotoxic, depending on the percentage of cell viability. The Wilcoxon test for intragroup comparison showed that the percentage of viable cells decreased significantly for extracts, for all composite resins tested. The composite resins contained monomers that displayed cytotoxic properties. BisGMA, TEGDMA and UDMA had inhibitory effects and induced apoptotic proteins in pulp fibroblast. Composite resins that contained lower percentages of unbound free monomers—and that released less ions—possessed superior biocompatibility in vitro.

Periodontal response to a tricalcium silicate material or resin composite placed in close contact to the supracrestal tissue attachment: a histomorphometric comparative study

OBJECTIVE

Subgingival dental restorations and periodontal health have been studied for many years; however, there is a low histological evidence on the behavior of new materials in the supracrestal tissue attachment. The aim of this study is to analyze the periodontal response when a tricalcium silicate material (TSM) or composite margin restorations is placed to 0.5 mm and 1.5 mm from the bone crest with a histomorphometric analysis in dogs.

METHODS

Nine mongrel dogs were used in this study: four dogs (8 canine teeth) for TSM group, 4 dogs (8 canine teeth) for composite group, and 1 dog (2 canine teeth) with cavities without restorations. Cavity preparation of 2×2×1 mm was created on the buccal aspect of the canines at 0.5 and 1.5 mm of the crestal bone. Cavities were restored with composite and TSM or were left unrestored as control. After 12 weeks of healing, the dogs were euthanized and blocks containing the tooth and soft tissues were processed.

RESULTS

In all the specimens, the junction epithelium was stablished apical to the tooth preparations. A shorter distance to the bone (0.5 cavity) implies greater apical periodontal migration regardless of the material used. In the TSM groups, the connective tissue height and the distance between bone level and apical margin preparation were greater than those in the composite groups, while the epithelium height was less. However, there were no statistically significant differences comparing TSM and composite groups at either 0.5 mm or 1.5 mm (p > 0.05).

CONCLUSION

Histologic analysis did not show periodontal reattachment to TSM or composite. In both cases, bone crest migrates apically. For that reason, it is recommended to perform composite restorations at the subgingival level whenever the distance to the bone crest is at least 2 mm.

CLINICAL RELEVANCE

Both composite and TSM do not achieve reinsertion of the connective tissue in the biological width.

Effects of cervical restorations on the periodontal tissues: 5-year follow-up results of a randomized clinical trial

OBJECTIVE

This study evaluated the effect of resin composite restorations of non-carious cervical lesions (NCCLs) on the occurrence/progression of gingival recession (GR), considering different tooth isolation techniques.

METHODS

A randomized controlled split-mouth and blinded trial was carried out. Patients (n = 38) with at least two NCCLs were included. Before the cervical restoration placement, the NCCLs (181 teeth) were randomly allocated into two treatment groups according to the tooth isolation techniques: cotton roll or rubber dam. Experienced, trained, blinded, and calibrated examiners performed periodontal evaluations at baseline and 5-year follow-up, using a periodontal probe. Restorations were assessed with the FDI criteria. Thirty-two patients (154 teeth) were evaluated at 5 years. The occurrence/progression of GR between baseline and follow-up was considered the primary outcome. The relative risk (RR) and 95 % confidence interval (95 %CI) were calculated by Poisson regression (α < 0.05).

RESULTS

After 5 year, 31 teeth (13.6 %) presented occurrence/progression of GR. In the multivariate analyses, the occurrence/progression of GR was associated with the use of rubber dam isolation (RR; 95 %CI: 2.65; 1.01-7.00) and a lack of marginal adaptation of the restoration (RR; 95 %CI: 10.98; 2.31-52.30). Toothbrush stiffness, use of abrasive dentifrice, tooth type, and the presence of biofilm or gingivitis did not present a statistically significant higher risk for occurrence/progression of GR.

CONCLUSION

The use of rubber dam isolation associated with retraction clamp and the lack of a proper marginal adaptation of the composite restorations are risk indicators for the occurrence/progression of GR in individuals who received a restoration for an NCCL.

CLINICAL SIGNIFICANCE

Isolation with a rubber dam and dental clamps may promote GR in sites with restored NCCLs. Moreover, clinical examinations for lack of marginal adaptations of the restorations may be included in a clinical setting.

The impact of fixed orthodontic appliances on oral microbiome dynamics in Japanese patients

Fixed orthodontic appliances are common and effective tools to treat malocclusion. Adverse effects of these appliances, such as dental caries and periodontitis, may be associated with alteration of the microbiome. This study investigated the impact of these appliances on the dynamics of the oral microbiome. Seventy-one patients were selected. Supragingival plaque samples were collected before placement (T0) and six months after placement (T1). Saliva samples were collected at T0 and T1, and then when appliance removal (T2). Microbial DNA was analyzed by 16S rRNA meta-sequencing. The diversity analysis indicated dynamic changes in the structure of the oral microbiome. Taxonomic analysis at phylum level showed a significant increase in Bacteroidetes and Saccharibacteria (formally TM7) and decrease in Proteobacteria and Actinobacteria over time, in both plaque and saliva. Genus level analysis of relative abundance indicated a significant increase in anaerobic and facultative anaerobes in both plaque and saliva. Fixed orthodontic appliances induced measurable changes in the oral microbiome. This was characterized by an increase in relative abundance of obligate anaerobes, including periodontal pathogens. It can be concluded that this dysbiosis induced by fixed orthodontic appliances is likely to represent a transitional stage in the shift in microbiome from healthy to periodontitis.

A Simple Method for Modifying the Emergence Profile by Direct Restorations: The Biologically Active Intrasulcular Restoration Technique

CLINICAL RELEVANCE

It is possible to modify the natural emergence profile of the tooth using simple intrasulcular direct restorations. The shape of the intrasulcular part of the restoration will determine the design of the gingival contour.

SUMMARY

Some clinical situations, such as the closure of pronounced diastemas and the transformation of malformed, small, or peg-shaped teeth, require a rebalancing of dental proportions accompanied by a modification of the gingival contour. A traditional treatment plan might require surgical, prosthetic, and/or orthodontic treatment, but in some cases, these therapeutic options could be considered too invasive and not always the best solution. Moreover, not all patients are ready to undergo irreversible, long, and expensive procedures. To overcome these limitations and to solve all of these clinical problems in a rapid and noninvasive way, we propose a new technique that allows us to modify the natural emergence profile of the tooth using simple intrasulcular direct restorations. Using the Biologically Active Intrasulcular Restoration technique, it is possible to rebalance tooth shape and dimensions, gingival level and contour with low biological and economic costs. This method, which does not require any preparation of the dental tissues, is reversible and minimally invasive. It is applicable to patients of all ages, and results are obtained in a single appointment.

Cytotoxicity of Different Nano Composite Resins on Human Gingival and Periodontal Ligament Fibroblast Cell Lines: An In Vitro Study

The aim of this study is to determine the cytotoxicity of three different nano composite resins (CRs) on human gingival fibroblast (hGF) and periodontal ligament fibroblast (hPDLF) cell lines. These CRs selected were nanohybrid organic monomer-based Admira Fusion (AF), nanohybrid Bis-(acryloyloxymethyl) tricyclo [5.2.1.0.sup.2,6] decane-based Charisma Topaz (CT), and supra nano filled resin-based Estelite Quick Sigma (EQS). MTT assay was performed to assess the cytotoxicity of CRs at 24 h and one week. AF and EQS applied on hGF cells at 24 h and one week demonstrated similar cytotoxic outcomes. Cytotoxicity of CT on hGF cells at one week was higher than 24 h (p = 0.04). Cytotoxicity of CT on hGF cells was higher at 24 h (p = 0.002) and one week (p = 0.009) compared to control. All composites showed higher cytotoxicity on hPDLF cells at one week than the 24 h (AF; p = 0.02, CT; p = 0.02, EQS; p = 0.04). AF and EQS demonstrated lower cytotoxicity on hPDLF cells than the control group at 24 h (AF; p = 0.01, EQS; p = 0.001). CT was found more cytotoxic on hPDLF cells than the control (p = 0.01) and EQS group (p = 0.008) at one week. The cytotoxicity of CRs on hGF and hPDLF cells vary, according to the type of composites, cell types, and exposure time.

Minimally invasive rehabilitation of the worn dentition: a case report utilising adhesive additive techniques and digital technologies

The management of the worn dentition presents an increasing challenge that is encountered more frequently in daily dental practice. The consequences of tooth wear tend to be multifactorial and while they may initially only involve the loss of surface enamel it can progressively lead to significant destruction of the dentition. This paper discusses the management of a tooth wear case where a significant amount of tooth structure has been lost from both the anterior and posterior teeth. Protocols for assessment, treatment planning and restorative management of the tooth wear case are presented demonstrating the use of adhesive additive techniques and digital technologies to achieve functional and aesthetic rehabilitation of the dentition.

Clinical evaluation of combined surgical/ restorative treatment of gingival recession-type defects using different restorative materials: A randomized clinical trial

Background/purpose

An ideal therapeutic procedure for the treatment of gingival recession associated with an NCCL has presented a challenge to clinicians. Various dental materials and surgical approaches have been used to manage gingival recessions associated with NCCLs for the most predictable combined surgical/restorative treatment. The objective of this study was to evaluate the treatment of gingival recessions associated with non-carious cervical lesions (NCCL) using a modified coronally advanced flap (MCAF) in combination with a connective tissue graft (CTG) on restored root surfaces.

Materials and methods

Twenty-three systemically healthy subjects, who were positive for the presence of three cervical lesions associated with gingival recessions in three different adjacent teeth, were enrolled in the study. The NCCL were each restored prior to surgery by using one of three different materials: nanofilled composite resin (NCR), resin-modified glass ionomer cement (RMGI) or giomer. The gingival recession defects were treated by CTG.

Results

Inter-group differences were not statistically significant for probing depth (PD), relative recession height (rRH), relative clinical attachment level (rCAL), keratinized tissue width (KTW) or keratinized tissue thickness (KTT) (p > 0.05) among the groups at any time. The mean percentage of defect coverage was 71.18 ± 23.16% for NCR + CTG group; 71.33 ± 22.33% for RMGI + CTG group; and 64.23 ± 20.33% for giomer + CTG group at 1 year postoperatively (p > 0.05).

Conclusion

The combined surgical/restorative treatments provided successful clinical results. Giomer + CTG may be less effective compared to other groups for treatment of gingival recession associated with NCCL.

Evaluation of biofilm formation on novel copper-catalyzed azide-alkyne cycloaddition (CuAAC)-based resins for dental restoratives

OBJECTIVE

For the past several decades, the resins used in dental restorations have been plagued with numerous problems, including their implication in biofilm formation and secondary caries. The need for alternative resins is critical, and evaluation of biofilm formation on these resins is essential. The aim of this study was to evaluate in vitro biofilm formation on the surface of novel copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC)-based resins and composites.

METHODS

CuAAC-based resins/composites made from varying azide monomers and different copper concentrations were compared with BisGMA-TEGDMA resins/composites that served as the control. Biofilms were formed using a mono-species model containing a luciferase-expressing strain of Streptococcus mutans. Luciferase activity was measured and the number of viable bacteria was enumerated on biofilms associated with each resin and composite.

RESULTS

A significant reduction (p<0.05) in luciferase activity, and the number of viable bacteria recovered from biofilms on CuAAC-based resins and composites was observed in comparison to biofilms associated with the BisGMA-TEGDMA controls.

SIGNIFICANCE

CuAAC-based resins do still allow for the formation of biofilms; however, the statistically significant reduction of growth that was associated with the CuAAC resin may enhance the longevity of restorations that incorporate CuAAC-based materials.

The effects of different restorative materials on periodontopathogens in combined restorative-periodontal treatment

Objective

The aim of the study was to evaluate the association between subgingival restorations and the target periodontopathogenic bacteria (Pg, Td and Pi) in subgingival biofilm during one year after combined restorative-periodontal treatment.

Material and Methods

Seventeen systemically healthy subjects, who were positive for the presence of three cervical lesions associated with gingival recessions in three different adjacent teeth, were included in the study. A total of 51 combined defects were treated with connective tissue graft plus a nanofilled composite resin (NCR+CTG), a resin-modified glass ionemer cement (RMGI+CTG) and a fluoride-releasing resin material with pre-reacted glass (PRG), called giomer (Giomer+CTG). Periodontal clinical measurements and subgingival plaque samples were obtained from all combined defects at baseline and at 6 and 12 months after the surgery. The number of bacteria were evaluated by the real-time polymerase chain reaction (qPCR) method.

Results

No statistically significant difference in the amount of DNA copies of Pg, Td and Pi was observed in any of the groups at any time points (p>0.05). In addition, there was no statistically significant difference in the amount of DNA copies of the bacteria at baseline and at 6 and 12 months postoperatively, regardless of treatment group (p>0.05).

Conclusion

This study suggests that subgingivally placed NCR, RMGI and giomer restorations can show similar effects on periodontopathogenic bacteria in the treatment of gingival recessions that are associated with noncarious cervical lesions (NCCLs).

Does Evidence Support a Combined Restorative Surgical Approach for the Treatment of Gingival Recessions Associated With Noncarious Cervical Lesions?

OBJECTIVES

Gingival recessions are frequently associated with noncarious cervical lesions. Combined restorative surgical approaches have been suggested for the management of these combined defects. The aim of this review was to analyze the current evidence on the effectiveness of these combined restorative surgical approaches.

METHODS

A systematic review of randomized controlled studies published from January 2006 to June 2016 was performed.

RESULTS

Ten articles comparing combined restorative surgical approaches to surgery alone were included. Both the procedures showed similar outcomes in term of root coverage but the combined restorative surgical approach achieved better result in the reduction of dentin hypersensitivity. In combined restorative surgical treatments, resin-modified glass ionomers showed better antimicrobial properties but poorer esthetic outcome than resin composites.

CONCLUSION

Data to support or refute definitely the interest of combined approaches for the treatment of gingival recessions associated with noncarious cervical lesions are limited.

Recognition and management of palatogingival groove for tooth survival: a literature review

Palatogingival groove (PGG) is an anomaly in the maxillary anterior teeth, often accompanied by the area of bony destruction adjacent to the teeth with no carious or traumatic history. The hidden trap in the tooth can harbor plaque and bacteria, resulting in periodontal destruction with or without pulpal pathologic change. Related diseases can involve periodontal destruction, combined endodontic-periodontal lesions, or separate endodontic and periodontal lesions. Disease severity and prognosis related to PGG depend on several factors, including location, range, depth, and type of the groove. Several materials have been used and recommended for cases of extensive periodontal destruction from PGG to remove and block the inflammatory source and recover the health of surrounding periodontal tissues. Even in cases of severe periodontal destruction, several studies have reported favorable treatment outcomes with proper management. With new options in diagnosis and treatment, clinicians need a detailed understanding of the characteristics, treatment, and prognosis of PGG to successfully manage the condition.

Mercury Amalgam Diffusion in Human Teeth Probed Using Femtosecond LIBS

In this work the diffusion of mercury and other elements from amalgam tooth restorations through the surrounding dental tissue (dentin) was evaluated using femtosecond laser-induced breakdown spectroscopy (fs-LIBS). To achieve this, seven deciduous and eight permanent extracted human molar teeth with occlusal amalgam restorations were half-sectioned and analyzed using pulses from a femtosecond laser. The measurements were performed from the amalgam restoration along the amalgam/dentin interface to the apical direction. It was possible to observe the presence of metallic elements (silver, mercury, copper and tin) emission lines, as well as dental constituent ones, providing fingerprints of each material and comparable data for checking the consistence of the results. It was also shown that the elements penetration depth values in each tooth are usually similar and consistent, for both deciduous and permanent teeth, indicating that all the metals diffuse into the dentin by the same mechanism. We propose that this diffusion mechanism is mainly through liquid dragging inside the dentin tubules. The mercury diffused further in permanent teeth than in deciduous teeth, probably due to the longer diffusion times due to the age of the restorations. It was possible to conclude that the proposed femtosecond-LIBS system can detect the presence of metals in the dental tissue, among the tooth constituent elements, and map the distribution of endogenous and exogenous chemical elements, with a spatial resolution that can be brought under 100 µm.

Do Dental Resin Composites Accumulate More Oral Biofilms and Plaque than Amalgam and Glass Ionomer Materials?

A long-time drawback of dental composites is that they accumulate more biofilms and plaques than amalgam and glass ionomer restorative materials. It would be highly desirable to develop a new composite with reduced biofilm growth, while avoiding the non-esthetics of amalgam and low strength of glass ionomer. The objectives of this study were to: (1) develop a protein-repellent composite with reduced biofilms matching amalgam and glass ionomer for the first time; and (2) investigate their protein adsorption, biofilms, and mechanical properties. Five materials were tested: A new composite containing 3% of protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC); the composite with 0% MPC as control; commercial composite control; dental amalgam; resin-modified glass ionomer (RMGI). A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate metabolic activity, colony-forming units (CFU), and lactic acid production. Composite with 3% MPC had flexural strength similar to those with 0% MPC and commercial composite control (p > 0.1), and much greater than RMGI (p < 0.05). Composite with 3% MPC had protein adsorption that was only 1/10 that of control composites (p < 0.05). Composite with 3% MPC had biofilm CFU and lactic acid much lower than control composites (p < 0.05). Biofilm growth, metabolic activity and lactic acid on the new composite with 3% MPC were reduced to the low level of amalgam and RMGI (p > 0.1). In conclusion, a new protein-repellent dental resin composite reduced oral biofilm growth and acid production to the low levels of non-esthetic amalgam and RMGI for the first time. The long-held conclusion that dental composites accumulate more biofilms than amalgam and glass ionomer is no longer true. The novel composite is promising to finally overcome the major biofilm-accumulation drawback of dental composites in order to reduce biofilm acids and secondary caries.

Influence of proximal box elevation technique on marginal integrity of adhesively luted Cerec inlays

OBJECTIVES

This in vitro study evaluated the marginal quality of Lava Ultimate inlays in deep proximal cavities with and without proximal box elevation (PBE) before and after thermomechanical loading (TML).

MATERIALS AND METHODS

Mesio-occluso-distal cavities with proximal boxes beneath the cementoenamel junction (CEJ) were prepared in 24 human molars. Then, one of the proximal boxes was elevated with Filtek Supreme above the CEJ. The specimens were divided into three groups (n = 8). The inlays of group A were adhesively luted to the cavities with Scotchbond Universal and Rely X Ultimate, the inlays of group B with Monobond Plus, Syntac, and Variolink II, and the inlays of group C with Clearfil Ceramic Primer and Panavia SA Cement. Epoxy resin replicas were taken before and after thermomechanical loading (1,200,000 cycles, 55 °C/5 °C, max. load 50 N). Marginal integrity at the different interfaces tooth/PBE, tooth/dentine, inlay/PBE, inlay/dentine was evaluated with scanning electron microscopy (×200). The percentage of continuous margin (% of total proximal margin length) was compared between the groups before and after TML.

STATISTICS

Mann-Whitney U test (p = 0.05).

RESULTS

No significant differences (p > 0.05) before and after TML were found between the three groups for bonding the inlay to dentine or to PBE composite.

CONCLUSIONS

The marginal integrities of bonding inlays directly to dentine are not different from bonding inlays to a proximal box, which has been elevated by a composite filling material. For deep proximal cavities, the PBE technique could be an alternative technique to conventional methods. Clinical research is needed to confirm.

Periodontal response to two different subgingival restorative margin designs: a 12-month randomized clinical trial

OBJECTIVES

Subgingival margin placement is sometimes required due to different reasons and is often associated with adverse periodontal reactions. The purpose of this study was to determine if a single restoration with subgingival margin on a tooth, in the maxillary anterior zone, would affect its periodontal soft tissue parameters, and whether or not a deep chamfer preparation has a different influence in the periodontium when compared to a feather edge preparation.

MATERIAL AND METHODS

Plaque and gingival indexes, periodontal probing depth, bleeding on probing, and patient's biotype were registered. One hundred six teeth were prepared with a deep chamfer, while 94 were prepared with a feather edge finishing line. Twelve months after the restoration delivery, the same parameters were evaluated. Repeated measure one-way analysis of variance (ANOVA) (α = 0.05) was used.

RESULTS

A statistically significant difference between the baseline and the 12-month follow-up is present in regard to plaque index, gingival index, and periodontal probing depth, but no statistically significant difference between chamfer and feather edge finishing lines. There is a statistically significant difference between the baseline and the 12-month follow-up in regard to bleeding on probing. Feather edge preparation presents significantly more bleeding on probing and less gingival recession than the chamfer.

CONCLUSIONS

Subgingival margins do influence the periodontal soft tissue response. Statistically significant difference exists between feather edge and chamfer finishing lines in regard to bleeding on probing and gingival recession.

CLINICAL RELEVANCE

Subgingival margins should be carefully selected, especially when feather edge finishing line is utilized.

Gingival Crevicular Fluid Levels of Neuropeptides following Dental Restorations

Purpose

Local neuropeptide release has a critical role in the initiation and progression of an inflammatory response. This study investigated the effects of different restorative materials on periodontium in this regard, by evaluating their neuropeptide-producing effects on gingival crevicular fluid (GCF).

Methods

The study included 14 patients suitable for metal-ceramic, composite and amalgam restorations. Four weeks after periodontal therapy, the restorations were performed. Study groups were constituted regarding the tooth/restoration surfaces contacting gingiva in each patient: 1 ceramic surface of a metal-ceramic crown (ceramic group), its opposite metal surface (metal group), 1 composite surface (composite group), its opposite enamel surface (opposite-composite group), 1 amalgam surface (amalgam group), its opposite enamel surface (opposite-amalgam group) and 1 nonrestored enamel surface (enamel group). Four weeks after dental restorations, clinical data and GCF were obtained from the group sites. Clinical data, GCF volume and its proinflammatory cytokine profile were utilized to evaluate the periodontal health. GCF levels of substance P (SP), neurokinin A (NKA) and calcitonin-gene related peptide (CGRP) were determined by ELISA for revealing the neuropeptide levels.

Results

GCF volume was found to increase in all groups compared with the enamel group (p<0.05). SP and NKA levels were higher in the ceramic, composite and amalgam groups than those in the enamel group (p<0.05). SP and NKA levels were also higher in the composite and amalgam groups than those in the opposite-composite/amalgam groups (p<0.05).

Conclusions

These results suggest that ceramic, composite and amalgam materials may uniquely trigger local neuropeptide release in periodontium.

Dentists' restorative decision-making and implications for an 'amalgamless' profession. Part 1: a review

The Minamata Convention has agreed to a worldwide reduction and ultimate elimination in the production and use of mercury containing products. This will have implications for the practice of dentistry. Australian organizations' pronouncements on the issue are limited and research examining the Australian context dated. The restoration of teeth with direct materials has changed significantly since the 1980s. Up to this time amalgam was the material of choice for direct posterior restorations. Its properties and guidelines for placement were, and remain, well established. Resin composite has replaced amalgam as the material of choice in many clinical situations. Despite inherent clinical disadvantages compared to amalgam, there continues to be a shift toward greater use of resin composite. There is consensus worldwide that the restoration of posterior teeth using resin composite now exceeds that of amalgam. The reasons for this are reviewed in this article along with current evidence and commentary relating to direct restorative and evidence-based decision-making, minimally invasive approaches, and approaches to education. The implications for these in an 'amalgamless' profession are identified.

The effects of silorane composites on levels of cytokines and periodontal parameters

Aims:

The purpose of this pilot study was to determine the effects of silorane composites on gingival crevicular fluid (GCF) levels of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and IL-8, GCF volume and clinical periodontal parameters in patients with silorane composite restorations before and after restorative treatment.

Materials and Methods:

A total of 20 systemically healthy non-smokers, 12 female and 8 male (age range: 24-46 years), presenting with 25 instances of primary dentine caries with subgingival margins were selected for this study. Approval was obtained from the university ethics committee and treatment plans were approved by the patients. GCF samples were obtained with periopaper strips from relevant teeth for IL-6, IL-8 and TNF-α measurements. Each sample was stored at − 80°C and analyzed using the enzyme-linked immunosorbent assay (ELISA) kits. Cavities were prepared according to the common principles for adhesive restorations and restored with a silorane adhesive system (Silorane System Adhesive (3M ESPE) and silorane composite (Filtek Silorane, 3M ESPE). Cytokine levels were reassessed 2 weeks after restorative treatment. Data were analyzed using the independent t-test at a significance level of α =0.05. Associations between parameters were analyzed using Pearson correlation analysis.

Results:

A significant increase in gingival index (GI) and plaque index (PI) were observed after 15 days (P < 0.05). GCF volume, IL-6, IL-8 and TNF-α levels exhibited significant differences before and after restorative treatment (P < 0.05). There were strong positive correlations among parameters except for PI/GCF volume and GI/GCF volume.

Conclusion:

Within the limitations of this investigation, silorane composites may have some negative effects on cytokine levels, clinical parameters and GCF volume.

Multilevel analysis of the association between posterior restorations and gingival health in young adults: a population-based birth cohort

OBJECTIVE

To investigate the association of direct posterior restorations with gingival bleeding and dental calculus in young adults from a birth cohort.

METHODS

A representative sample (n = 720) of 5914 infants born live in Pelotas, Brazil, in 1982, were prospectively investigated, and posterior restorations and periodontal health outcomes assessed when they were 24 years of age. Tooth-level exploratory variables included the presence and number of restoration's surfaces. Demographic and socio-economic characteristics, oral health instructions, dental floss usage, dental caries presence and smoking were also considered whilst gingival bleeding and dental calculus were the outcomes. Multilevel logistic regression was carried out.

RESULTS

Class I cavities were found in 15.2% (95% CI 14.5-15.9) of the teeth and class II in 3.6% (3.3-4.0). Percentage of teeth with gingival bleeding was 6.1% (5.6-6.6) and that with dental calculus 22% (21.2-22.8). Even after all the individual variables were controlled for, the presence of a class I [OR1.51 (1.14-2.00)] and class II [OR 1.76 (1.04-2.97)] cavities was positively associated with gingival bleeding. Class I [OR1.36 (1.13-1.65)] and Class II [OR1.80 (1.28-2.53)] cavities were associated with dental calculus also.

CONCLUSIONS

Posterior restoration and higher number of restored surfaces was associated with a higher prevalence of gingival bleeding and dental calculus around the restoration.

Influence of a proximal margin elevation technique on marginal adaptation of ceramic inlays

PURPOSE

Evaluating the effect of a proximal margin elevation technique on marginal adaptation of ceramic inlays.

METHODS

Class II MOD-cavities were prepared in 40 human molars and randomly distributed to four groups (n = 10). In group EN (positive control) proximal margins were located in enamel, 1 mm above the cementoenamel junction, while 2 mm below in groups DE-1In, DE-2In and DE. The groups DE-1In, DE-2In and DE simulated subgingival location of the cervical margin. In group DE-1In one 3 mm and in group DE-2In two 1.5 mm composite layers (Tetric) were placed for margin elevation of the proximal cavities using Syntac classic as an adhesive. The proximal cavities of group DE remained untreated and served as a negative control. In all groups, ceramic inlays (Cerec 3D) were adhesively inserted. Replicas were taken before and after thermomechanical loading (1.200.000 cycles, 50/5°C, max. load 49 N). Marginal integrity (tooth-composite, composite-inlay) was evaluated with scanning electron microscopy (200×). Percentage of continuous margin (% of total proximal margin length) was compared between groups before and after cycling using ANOVA and Scheffé post-hoc test.

RESULTS

After thermomechanical loading, no significant differences were observed between the different groups with respect to the interface composite-inlay and tooth-composite with margins in dentin. The interface tooth-composite in enamel of group EN was significantly better compared to group DE-2In, which was not different to the negative control group DE and DE-1In.

CONCLUSION

Margin elevation technique by placement of a composite filling in the proximal box before insertion of a ceramic inlay results in marginal integrities not different from margins of ceramic inlays placed in dentin.

Clinical attachment level gain and bone regeneration around a glass ionomer restoration on root surface wall of periodontal pocket

A case describing perio-restorative management of an accidental trauma in the mid portion of root on an upper left canine tooth following an ostectomy surgery is presented here. The traumatized root area was undergoing fast resorption and a chronic periodontal abscess had developed in relation to the lesion. The article illustrates the clinical and radiographic photo series of a periodontal flap surgery done to gain access into a subgingival region for the placement of Glass ionomer restoration on the root and its periodic follow up. The clinical condition of the area suggests 8 mm clinical attachment gain over the restoration and the review radiographs at definite intervals up to 18 months revealed evidence of consistent bone regeneration around the restoration. The article also highlights the various other possibilities, where this restorative material can be effectively used in conjunction with periodontal surgical procedures.

Microbiological and Biochemical Effectiveness of an Antiseptic Gel on the Bacterial Contamination of the Inner Space of Dental Implants: A 3-Month Human Longitudinal Study

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

Effects of glass ionomer and microfilled composite subgingival restorations on periodontal tissue and subgingival biofilm: a 6-month evaluation

BACKGROUND

This 6-month study evaluated the effects of resin-modified glass-ionomer cement (RMGI) and microfilled composite (MC) subgingival restorations on periodontal tissues and subgingival biofilm.

METHODS

Fifty-four periodontally healthy patients were assigned as follows: group 1 (N = 18), root exposure (RE) without non-carious cervical lesions (NCCL) treated with coronally positioned flap (CPF); group 2 (N = 18), RE with NCCL treated RMGI restorations plus CPF; group 3 (N = 18), RE with NCCL treated with MC restorations plus CPF. Probing depth (PD), visible local plaque score (PL), and local bleeding on probing (BOP) were assessed at baseline and 6 months after surgeries. Restored and non-restored root recoverage (RR) was assessed at 6 months. Each experimental tooth was subgingivally sampled (baseline and 6 months) and analyzed by checkerboard DNA-DNA hybridization.

RESULTS

Clinical results showed no significant differences among the groups regarding PL, BOP, and PD at baseline and 6 months. The RR means were similar among the groups at 6 months. Intragroup analyses revealed that the proportions of 10 periodontopathogens decreased at 6 months for the control group. For the RMGI group, there was a significant decrease in the proportions of nine periodontopathogens. For the MC group, there was a significant increase in the proportions of Fusobacterium nucleatum polymorphum and Gemella morbillorum and a decrease in five periodontopathogens. Intergroup analyses showed an increase in the proportion of F. nucleatum polymorphum for the MC group.

CONCLUSIONS

In a 6-month evaluation, well-finished RMGI or MC subgingival restorations did not negatively affect periodontal health. Furthermore, RMGI seems to exert more positive effects on the subgingival biofilm composition than MC.

Periodontal Tissue Response to Coverage of Root Cavities Restored With Resin Materials: A Histomorphometric Study in Dogs

BACKGROUND

The purpose of this study was to histomorphometrically evaluate the response of periodontal tissues covering Class V resin restorations in dogs.

METHODS

After raising a mucoperiosteal flap, bony defects measuring 5 x 5 mm were created on the buccal aspect of the canines of five dogs followed by cavity preparations on the root surface measuring 3 x 3 x 1 mm. Before repositioning the flap to cover the bone defect, the cavities were restored with composite resin (CR) or resin-modified glass ionomer cement (RMGIC) or were left unrestored as control (C). The dogs were euthanized 90 days after surgery. Specimens comprising the tooth and periodontal tissues were removed, processed routinely, cut into longitudinal serial sections in the buccolingual direction, and stained with hematoxylin and eosin (H&E) or Masson's trichrome. The most central sections were selected for histomorphometric analysis.

RESULTS

Histomorphometric analysis revealed apical migration of epithelial tissue onto the restorative materials (RMGIC and CR). The C group presented significantly longer connective tissue attachment (P <0.05) than the RMGIC and CR groups and significantly higher bone regeneration (P <0.05) compared to the RMGIC group. Histologically, the cervical third (CT) of all groups had the most marked chronic inflammatory infiltrate.

CONCLUSIONS

Within the limits of this study, it can be concluded that the restorative materials used exhibit biocompatibility; however, both materials interfered with the development of new bone and the connective tissue attachment process.

Effects of Thermal Cycling on Surface Texture of Restorative Composite Materials

The purpose of this study was to evaluate the effect of thermal cycling on the surface texture of restorative materials. Disk-shaped specimens made of seven resin composites (Beautifil: BF; Esthet-X: EX; Filtek Supreme: FS; Inten-S: IS; Point 4: PT; Solare: SR; and Venus: VS) were finished with 1-microm alumina suspension, and then thermocycled between 4 and 60 degrees C in distilled water for 20,000 or 50,000 cycles with a dwell time of 60 seconds. Staining susceptibility and mean surface roughness, Ra, were examined, and surface texture was observed by scanning electron microscopy. Dye penetration test showed that the surfaces of all resin composites were more stained after thermal cycling. Mean Ra of all resin composites, except PT, significantly increased after 50,000 thermal cycles. Dislodgement of filler particles was observed for all resin composites after thermal cycling, except FS. It was concluded that thermal cycling significantly affected the surface texture of the seven examined resin composites.

Dental restorations: a risk factor for periodontal attachment loss?

BACKGROUND

Dental caries and restorations in proximal tooth surfaces often impinge upon the periodontal biological width.

AIM

This study examines whether these factors may contribute to risk for periodontal attachment loss at these sites.

METHODS

The study is based upon data from the Dunedin Multidisciplinary Health and Development Study, a long-standing cohort study. Approximal tooth surfaces of 884 study members were evaluated for restorations and caries at age 26 and again at 32 years, and probing depth and gingival recession were recorded in millimetres at age 32. Attachment loss was computed as the sum of pocket depth and gingival recession. Data were analysed using generalized estimating equations.

RESULTS

Where a caries/restorative event had occurred on an inter-proximal tooth surface before age 26, the age-32 attachment loss at the corresponding periodontal site was approximately twice more likely to be >or=3 mm than if the adjacent tooth surface had remained sound to age 32. This was also true where a caries/restorative event had occurred subsequent to age 26. The association remained after controlling for potential confounders, including smoking.

CONCLUSIONS

Site-specific periodontal attachment loss due to dental caries or restorative events occurs in adults in their third and fourth decades of life.

Changes in the subgingival microbiota and periodontal parameters before and 3 months after bracket placement

INTRODUCTION

Dental plaque is organized in a biofilm complex that provides protection and nutrients for periodontopathic bacteria. Several factors can affect microbial colonization, including restorations and orthodontic brackets. The aim of this study was to investigate changes in subgingival microbiota and clinical parameters before and after bracket placement.

METHODS

Clinical parameters and subgingival microbial samples were collected from 30 patients before and after bracket placement. Thirty additional patients with no orthodontic treatment served as controls. Samples were cultured and analyzed for periodontopathic and superinfecting bacteria. A descriptive analysis was conducted, and chi-square, Student t, Wilcoxon matched, and Mann Whitney rank sum tests were used to test for differences between groups (P < or=.05).

RESULTS

No changes in probing depth or clinical attachment level were observed, but scores for bleeding on probing, plaque index, and gingival index increased after bracket placement (P < or =.05). Porphyromonas gingivalis, Prevotella intermedia/Prevotella nigrescens, Tannerella forsythia, and Fusobacterium species were elevated in the experimental group after bracket placement compared with the control group (P < or =.01). Superinfecting microorganisms such as Enterobacter cloacae, Klebsiella oxytoca, Klebsiella pneumoniae, and Serratia marcescens were also found.

CONCLUSIONS

Bracket placement influences the accumulation of plaque and the colonization of important periodontopathic and superinfecting bacteria, resulting in more inflammation and bleeding. Special attention should be paid to oral hygiene methods in orthodontic patients.

Effect of Whitening Dentifrices on the Superficial Roughness of Esthetic Restorative Materials

PURPOSE

The purpose of this study was to investigate the surface roughness (Ra) of different esthetic restorative materials following simulated toothbrushing using different whitening dentifrices.

MATERIALS AND METHODS

Cylinders of Esthet-X (Dentsply Caulk, Milford, DE, USA), Durafil VS (Heraeus Kulzer, Wehrheim, Germany), and Vitremer (3M ESPE, St. Paul, MN, USA) were made using molds (4 mm in diameter for 2 mm in height). The superficial roughness was evaluated using a profilometer (Ra) with a cutoff length of 0.25 mm and a speed of 0.1 mm/s. The specimens (N=13) were submitted to 7,500 brushing cycles using five different toothpastes: (1) Crest Regular (control; Procter & Gamble): silica abrasive (C); (2) Crest Extra Whitening (Procter & Gamble, Cincinnati, OH, USA): bicarbonate+calcium pyrophosphate (CE); (3) Dental Care A & H (Arm & Hammer, Camilla, GA, USA): bicarbonate (DC); (4) Rembrandt Plus Whitening (Oral B Laboratories, Belmont, CA, USA): carbamide peroxide+alumina/silica (RP); and (5) experimental: hydrogen peroxide+calcium carbonate (EX).

RESULTS

The data were analyzed by analysis of variance and Tukey's test (alpha=.05) for each restorative material, and the results [difference between final and initial roughness: Ra(F)-Ra(I) in microm] were as follows: Esthet-X: EX=0.15+0.07a; RP=0.29+0.16a; CE=0.96+0.33b; C=1.03+0.29b; DC=1.48+0.37b; Durafil VS: RP=0.09+0.07a; EX=0.55+0.23abc; C=0.96+0.26bc; CE=1.03+0.33cd; DC=1.09+0.37d; and Vitremer: EX=0.10+0.08a; RP=0.26+0.19a; CE=0.94+0.27b; DC=1.13+0.46bc; C=1.50+0.32c (different letters mean differences among groups).

CONCLUSION

It was verified that the dentifrices containing carbamide or hydrogen peroxide along with alumina+silica and calcium carbonate, respectively (groups 4 and 5), produced minor changes in Ra when compared with the control group and with those dentifrices containing bicarbonate (groups 2 and 3). CLINICAL significance The results of this study indicate that whitening dentifrices evaluated containing silica or calcium carbonate were less abrasive when used on the resin-based esthetic restorative materials than those that contain sodium bicarbonate.

Clinical performance of posterior metal-free polymer crowns with and without fiber reinforcement: one-year results of a randomised clinical trial

OBJECTIVES

The aim of this study was to evaluate the clinical performance of posterior, metal-free polymer crowns with and without a glass-fiber framework, in comparison to metal-ceramic crowns.

METHODS

After randomisation, 80 single crowns, manufactured from a newly designed polymer composite, were set in posterior teeth. Half of these received a glass-fiber framework, while half were prepared without any framework stabilisation. All polymer crowns were adhesively luted with resin cement. As the control group, 40 conventional metal-ceramic crowns were inserted with hybrid cement. Documentation included failures and other complications, as well as gingival/plaque status and aesthetic performance.

RESULTS

During the 12-month observation period, eight polymer crowns and three metal-ceramic crowns showed clinically relevant complications. The most frequent complications were root canal treatments (n=4) and decementation (n=4) of the crowns. A total of two crowns (one polymer crown with fiber network and one crown of the control group) had to be replaced. After 12 months, polymer crowns with glass-fiber framework exhibited significantly higher plaque accumulation (p=0.005) and gingival index (p=0.04) than metal-ceramic crowns, while no significant differences could be demonstrated for polymer crowns without fiber reinforcement. Postoperative sensibility and aesthetic performance did not differ significantly between the groups.

CONCLUSIONS

Within a 12-month observation period, posterior polymer crowns with and without glass-fiber framework demonstrated acceptable stability and aesthetic performance. Polymer crowns with fiber framework showed significant higher plaque accumulation and gingival index than metal-ceramic crowns.

Development and characterization of a simple perfused oral microcosm

AIMS

To validate perfused, inline, filter-based fermentation systems (multiple Sorbarod devices, MSD) for their ability to maintain stable oral bacterial communities. MSD enable replicate (n=5) microcosm biofilms (BF) to be established and sampled, together with their perfusates (PA, cells in eluted medium).

METHODS AND RESULTS

Fresh saliva from human volunteers was used to inoculate MSD, incubated in an anaerobic cabinet and perfused with artificial saliva at 7 ml h(-1). BF within Sorbarod filters and cells eluted in the PA were analysed at 24-h intervals by differential bacteriological culture and checkerboard DNA-DNA hybridization (CKB, 40 oral species). Dynamic stability was apparent after 2-3 days within both BF and PA as evidenced by culture, CKB data and pH measurements. BF harboured large numbers of anaerobic species and facultative anaerobes [ca 10-11 log10 colony-forming units (CFU)/filter] comprising considerable numbers of streptococci and Gram-negative species. PA contained ca 9-10 log(10) CFU ml(-1) suggesting an apparent mean growth rate of 0.1 h(-1) for the BF, as a whole corresponding to a mean generation time of 10 h. CKB analysis revealed considerable bacterial diversity within the respective MSD. Inter-individual variations in the relative species abundance of inocula was broadly reproduced in the MSD (BF and PA), although considerable variation was apparent between triplicate models established using saliva from one saliva donor or from three individual donors. The dominance of Gram-negative species, indicated by culture was supported by CKB analysis (major species, Prevotella melaninogenica and Fusobacterium nucleatum).

CONCLUSIONS

Data obtained from the various analytical approaches showed a high degree of congruence. The MSD enables the maintenance of complex, stable salivary microcosms and represents a simple, reproducible tool for modelling individual oral bacterial ecosystems.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrates the utility of the MSD for studying the micro-ecology of the oral cavity.