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A gummy smile is the visualization of more than 3 mm of gingiva above the maxillary incisors. This study aimed to evaluate the long-term effects on aesthetics and patient satisfaction of a new hyaluronic acid infiltration technique in reducing the gummy smile. Fifty patients with gummy smiles were treated using hyaluronic acid infiltration points by applying 0.1 mL per injection at specific points. Post-treatment evaluations were performed one week, one month, three months, six months, and 12 months later. A questionnaire assessed patient satisfaction, willingness to recommend the treatment, and side effects (pain and bruising during and after treatment). An average reduction of 2.5 mm in gingival exposure during smiling was observed. After one week, the reduction was constant. At six months, 40% of the original gingival exposure was recovered, and recovery was complete at 12 months. Patient satisfaction was 82.1%, and 100% of patients would recommend the treatment. Bruising, swelling, and pain decreased to 0% from the first month. In conclusion, this technique is a safe and effective option to improve the smile's appearance with minimal complications. [ABSTRACT FROM AUTHOR]

A gummy smile, defined as excessive gingival exposure while smiling, is an esthetic and functional condition affecting an individual's quality of life. Despite its prevalence and impact, the classification and treatment of the gummy smile remain challenging in clinical practice. The problem lies in (1) the fact that the etiology of this pathology is multifactorial, and these factors sometimes go unnoticed, (2) the lack of consensus on the classification criteria, which, together, create (3) challenges in designing an optimal treatment plan for each patient. This article reviews the etiologic factors of this condition as the main basis for understanding the existing classifications of the gummy smile. It highlights the importance of muscle dynamics in the genesis and treatment of this clinical condition. We present a new, treatment-oriented classification that integrates the muscle hyperactivity present within the classification criteria and explore the implication of this interaction in the design of effective treatments. The ultimate goal of this present work is to improve the clinical understanding of the gingival smile and offer more personalized treatment strategies, through a more complete classification. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the influence on peri‐implant crestal bone loss exerted by the vertical mucosal thickness and the abutment height over 12 months after placement of the restoration on subcrestal implants with change of platform, using a restoration abutment platform smaller than the implant platform. Materials and Methods: A total of 99 implants were rehabilitated in the maxillary and mandibular posterior regions. A total of 22 implants were rehabilitated in the maxilla and 77 implants in the mandible, using digitally designed customized abutments with Atlantis weborder software, from the commercial house Dentsply Sirona (Dentsply Sirona S.A., Barcelona, Spain), version 4.6.5, adapting the height to the vertical thickness of the mucosa. Clinical and radiographic monitoring begins during the surgical procedure of placement of the implant and ends 12 months afterwards. Crestal bone loss was evaluated through the Carestream® CS8100 3D radiographic equipment. Results: In all cases, the greatest loss of marginal bone occurred between the day of surgery (Tx) and placement of the rehabilitation (To). The average bone loss between both times was greater when the abutment height and vertical mucosal thickness did not exceed 3 mm. Subsequently, bone loss slowed and stabilized at 12 months. Conclusions: The minimum abutment height and the vertical mucosal thickness are factors to take into account when minimizing peri‐implant marginal bone loss, the abutment height having the greatest importance according to the clinical data obtained. [ABSTRACT FROM AUTHOR]

Background: Sealing the peri-implant tissue is a determining factor for long-term implant survival. In the transmucosal region, the cervical fraction of the prosthetic crown is in contact with these tissues, so mucointegration will also be influenced by the biomaterial used for the prosthetic restoration. This study aims to compare the tissue response generated by definitive restorative materials and polymeric materials from a histological point of view. Methods: This study performed an observational prospective cohort study in which biopsies of the peri-implant mucosa were taken after placement of implant-supported prosthetic restorations made of different materials (zirconium oxide, lithium disilicate, and PMMA). Results: A statistically significant difference was observed in the increase in the thickness of the non-keratinized epithelium when comparing the definitive materials (zirconium oxide/lithium disilicate) vs. the provisional material (PMMA) and in the number of collagen fibers when comparing zirconium oxide and lithium disilicate. Conclusions: This study found that zirconia is the material that presents the most adequate biological response of peri-implant tissues. It shows a lower intensity of inflammatory cellular content, a total normality in the number of collagen fibers (the arrangement of the fibers is normal in 90% of the cases), and vascular proliferation of connective tissue in 83% of the cases. These parameters make it a material with a predictable response. Similarly, only the following slight statistically significant differences between the definitive and provisional materials are observed, indicating that the biological response generated by the provisional material (PMMA) is not very different from that obtained with the placement of the definitive restoration. [ABSTRACT FROM AUTHOR]

Chlorhexidine (CHX) is one of the most widely used antiseptics in the oral cavity due to its high antimicrobial potential. However, many authors have stated that the effect of CHX in nonsurgical periodontal therapy is hampered by its rapid elimination from the oral environment. The aim of this study was to determine the antibacterial efficacy of a new compound of chlorhexidine 0.20% + cymenol (CYM) 0.10% on a multispecies biofilm. For this, an in vitro study was designed using a multispecies biofilm model of Streptococcus mutans, Fusobacterium nucleatum, Prevotella intermedia, and Porphyromonas gingivalis. Quantification of the microbial viability of the biofilm was performed using 5-cyano-2,3-ditolyl tetrazolium-chloride (CTC) to calculate the percentage of survival, and the biofilms were observed using a a confocal laser scanning microscopy (CLSM). It was observed that the bactericidal activity of the CHX + cymenol bioadhesive gel was superior to that of the CHX bioadhesive gel, in addition to higher penetrability into the biofilm. Therefore, there was greater elimination of bacterial biofilm with the new compound of chlorhexidine 0.2% plus cymenol 0.1% in a bioadhesive gel form compared to the formulation with only chlorhexidine 0.2% in a bioadhesive gel form. [ABSTRACT FROM AUTHOR]

(1) Background: Mucointegration seems to gain interest when talking about success in the maintenance of dental implants. As we well know, collagen fibres cannot be inserted due to the lack of root structure on the implant surface, so the structural integration of peri-implant tissues that provide a firm seal around implants seems to be of interest when it comes to ensuring the survival of dental implants. To achieve a good epithelial barrier, the physicochemical characteristics of the surfaces of the restorative materials are of vital importance; therefore, the objective of this study is to analyse the histological behaviour of the peri-implant soft tissues in three different restorative materials. (2) Methods: Histological analysis of biopsied peri-implant keratinised mucosa, inflammatory epithelium and connective tissue in contact with a reinforced composite (BRILLIANT Crios), a cross-linked polymethylmethacrylate (TELIO CAD), and a hybrid ceramic (Vita Enamic), restored on a customised Atlantis-type abutment (Dentsply Sirona) between 60 and 180 days after restoration. (3) Results: A greater number of cells per mm2 of keratinised epithelium is observed in the reinforced composite, which could indicate greater surface roughness with greater inflammatory response. In this way, the greater number of lymphocytes and the lateral cellular composition of the inflammatory cells confirm the greater inflammatory activity towards that material. The best material to rehabilitate was hybrid ceramic, as it shows a better cellular response. (4) Conclusions: Knowing the limitations of the proposed study, despite the fact that greater inflammation is observed in the reinforced composite relative to the other materials studied, no statistically significant differences were found. [ABSTRACT FROM AUTHOR]

Down syndrome patients show success rates in dental implants much lower than those observed in the general population. This retrospective case-control study aimed to identify possible genes that are related to the regulation of inflammatory responses and bone metabolism related to periimplantitis and implant loss, as well as genes related to bone quality. This process involved using the functional analysis of the gene expression software Transcriptome Analysis Console (TAC version 4.0 Applied BiosystemsTM, Thermo Fisher Scientific, Waltham, MA, USA) and a search for possible candidate genes involved. The focus was placed on the 93 genes related to periodontitis, periimplantitis, bone loss, implant loss, and genes related to bone quality and regulators underlying the establishment and maintenance of osseointegration. Five genes showed statistically significant results (p < 0.05) in our comparison. Four of them, IL1B (p = 0.023), IL1RN (p = 0.048), BGLAP (p = 0.0372) and PTK2 (p = 0.0075) were down-regulated in the periodontal disease and implant rejection group, and only one was overexpressed: FOXO1A (p = 0.0552). The genes with statistically significant alterations described in this article determine that the group of Down syndrome patients with periodontal disease and implant failure is a group of patients genetically susceptible to suffering from both conditions together. [ABSTRACT FROM AUTHOR]

Metallothioneins (MTs) are low molecular weight cysteine-rich proteins that can bind up to seven zinc ions. Among their numerous functions, MTs appear to act as protectors against oxidative and inflammatory injury. In our first published study, we reported downregulation of the isoforms MT1B (fold distance (FD) −2. 95; p = 0.0024), MT1F (FD −1.72; p = 0.0276), MT1X (FD −3.09; p = 0.0021), MT1H (FD −2.39; p = 0.0018), MT1M (FD −2.37; p = 0.0092), MT1L (FD −2. 55; p = 0.0048), MT1E (FD −2.71; p = 0.0014), MT2A (FD −2.35; p = 0.0072), MT1G (FD −2.24; p = 0.0118), and MT1A (FD −2.82; p = 0.0023) by comparing Down's syndrome patients with periodontal disease and implant failure to those without periodontal disease and with a positive progression of their implants. In this gene validation study, we intended to verify the results of our first gene expression analysis. Materials and Methods: In our retrospective case–control study, we performed retrotranscription (RT-qPCR) of 11 RNA-to-cDNA samples using the SuperScript™ VILO™ kit (50; reference 1,176,605) from Thermo Fisher. We conducted the study using the real-time PCR technique on the q-PCR ViiA 7 platform from Thermo Fisher. We chose the format of the Taqman Array Plate 16 Plus (reference 4,413,261) from Thermo Fisher, which accommodates 12 genes plus four controls (GAPDH, 18S, ACTB, and HPRT1). We conducted the analysis of the plates using the Thermo Fisher Cloud Web Software. Results: The results obtained through gene validation analysis show that in PD+RI+ patients, the genes encoding the isoforms MT1F (FD 0.3; p = 0.039), MT1X (FD 338; p = 0.0078), MT1E (FD 307; p = 0.0358), and MT2A (FD 252; p = 0.0428) continue to show downregulation, whereas MT1B (FD 2.75; p = 0.580), MT1H (FD 281; p = 0.152), MT1L (FD 354; p = 0.0965), and MT1G (FD 336; p = 0.0749) no longer show statistically significant results. [ABSTRACT FROM AUTHOR]

Repairing bone defects in oral surgery often requires the use of bone regeneration techniques. Silicon is an element that has been employed as regeneration material in several studies. In our study, silicon was combined with autologous bone and platelet-rich fibrin (PRF) membranes to analyse the behaviour of this element in bone regeneration. Four circumferential defects were created in the cranial vault of five New Zealand rabbits. The following elements were applied to the regeneration of the defects: (P): PRF; (S): silicon and (B): autologous bone, with the following distribution of study groups: Group 1 (PSB); Group 2 (PS); Group 3 (SB) and Group 4 (CONTROL): unregenerate group. The animals were sacrificed after 3 weeks. Computed microtomography studies (μ-CT) were carried out, as well as histomorphometric ones. The ANOVA statistical test was used with a Bonferroni post-hoc test to compare the results (p ≤ 0.05). Radiologically, groups PSB and SB were better as far as quantity and percentage of healthy bone observed, but not significantly compared to the control group. The PS group was significantly worse. The histological test revealed that the PSB group was the one to present the largest area, percentage and perimeter of mineralised bone. On evaluating the forming bone (osteoid), no difference was observed across the groups with the exception of the bone perimeter, where the SB group was significantly better. The bone height variable showed no significant differences. In conclusion we can state that the combination of PRF, autologous bone and silicon provides good results at 3 weeks whilst the PS group shows the worst results. This highlights the importance of autologous bone forming part of the graft material in order for the bone to mineralise. [ABSTRACT FROM AUTHOR]

The novelty of this study is the addition of an ultrathin layer of nanostructured hydroxyapatite (HA) on oxygen plasmamodified poly(lactic-co-glycolic) (PLGA)membranes (PO2) in order to evaluate the efficiency of this novel material in bone regeneration. Methods: Two groups of regenerative membranes were prepared: PLGA (control) and PLGA/PO2/HA (experimental). These membranes were subjected to cell cultures and then used to cover bone defects prepared on the skulls of eight experimental rabbits. Results: Cell morphology and adhesion of the osteoblasts to the membranes showed that the osteoblasts bound to PLGAwere smaller andwith a lower number of adhered cells than the osteoblasts bound to the PLGA/PO2/HA membrane (p < 0.05). The PLGA/PO2/HA membrane had a higher percentage of viable cells bound than the control membrane (p < 0.05). Both micro-CT and histological evaluation confirmed that PLGA/PO2/HA membranes enhance bone regeneration. A statistically significant difference in the percentage of osteoid area in relation to the total area between both groups was found. Conclusions: The incorporation of nanometric layers of nanostructured HA into PLGA membranes modified with PO2 might be considered for the regeneration of bone defects. PLGA/PO2/HA membranes promote higher osteosynthetic activity, new bone formation, and mineralisation than the PLGA control group. [ABSTRACT FROM AUTHOR]

To ensure similar primary implant stability measured by resonance frequency analysis (RFA) could be obtained in different jawbone densities by using a specific surgical drilling protocol and, to correlate those RFA measurements with factors related to the implant design, width, and length, we are performed a 1-year prospective clinical study was carried out using 27 subjects. A total of 67 hydrophilic titanium implants were placed using a standard 2-stage implant placement protocol. The bone type at each implant site was determined by evaluation of a preoperative, high-resolution cone beam computerized tomography (CBCT) scan. A modified drilling protocol was used in softer bone (types 2, 3, and 4) that allowed for greater implant thread contact with the surrounding bone. The implant stability quotient (ISQ) was measured at 4 different times during the study: initially it was determined immediately after implant placement, then again at stage 2 uncovering surgery, then at 6 months' postplacement and, and finally at 1 year postplacement. Data collected immediately after implant surgery demonstrated a high correlation (R2 = .99) between the ISQ and bone type classification. An overall trend toward a higher ISQ was found over the 1-year study period for all types of bone. Implants remained clinically and radiographically stable during the 1-year study period. Our data allow conclude that the primary stability of 2-staged loaded implants placed in different bone types can be optimized by applying this surgical drilling protocol during the implant placement. The ISQ method was found to be a reliable predictor of implant stability. [ABSTRACT FROM AUTHOR]

Bruxism is an unconscious, involuntary and sustained motor activity that results in excessive teeth grinding or jaw clenching that could affect patients' implants and rehabilitations. The aetiology for bruxism remains unknown, but it is known to involve multiple factors. The literature lacks studies on the possible effect of implant morphology on the resistance of the bone-implant osseointegrated interface when bruxism is present. Our objective is to assess the mechanical response of the bone-implant interface in bruxist patients whose implant prostheses are subjected to parafunctional cyclic loading over a simulated period of 10 years. A comparison was carried out between two implant types (M-12 and Astra Tech), and a pattern of bone loss was established considering both the stress state and the cortical bone surface loss as the evaluation criteria. Numerical simulation techniques based on the finite element analysis method were applied in a dynamic analysis of the received forces, together with a constitutive model of bone remodelling that alters the physical properties of the bone. The simulated cortical bone surface loss at the implant neck area was 8.6% greater in the Astra implant than in the M-12 implant. Compared to the M-12 implant, the higher sustained stress observed over time in the Astra implant, together with the greater cortical bone surface loss that occurred at its neck area, may be related to the major probability of failure of the prostheses placed over Astra implants in bruxist patients. [ABSTRACT FROM AUTHOR]

(1) Background: In today's dentistry, implantology has become a therapeutic resource of choice in certain clinical situations. The design of implants has evolved in several aspects since their inception. Dental implants were initially designed with an external hex connection, although due to force transmission and security in the adjustment of the prosthesis, later implants featured an internal hex connection. This study aims to analyse the mechanical properties of two types of implants (an internal connection and an external connection) from the same manufacturer and their different prosthetic components (union screw between implant and prosthetic abutment, and the abutment itself) when subjected to different types of load. (2) Materials and methods: Intraosseous dental implants of similar shape, design and size, although different in type of connection (external vs. internal), were studied. The specifications of the UNI EN ISO 14801 test standard were used, with all determinations being carried out three times. Finally, the dimensional characterisation of the samples analysed after the dynamic load study was carried out, and the values of both study groups were compared by means of the non-parametric Mann–Whitney U test to find statistically significant differences (p < 0.05). (3) Results: For the static characterisation test, we found between 610.9 N and 986.1 N for the external connection and between 1263.6 N and 1324 N for the internal connection (p = 0.011). All of the dynamic load tests were positive and there was no failure in any of the components studied. (4) Conclusions: After the analysis of the samples studied in vitro, satisfactory results were obtained, demonstrating that both connections can support considerable mechanical loads according to international standards (UNI EN ISO 14801). [ABSTRACT FROM AUTHOR]

Aim: Titanium implants are commonly used as replacement therapy for lost teeth and much current research is focusing on the improvement of the chemical and physical properties of their surfaces in order to improve the osseointegration process. TiO2, when it is deposited in the form of pillar array nanometric structures, has photocatalytic properties and wet surface control, which, together with UV irradiation, provide it with superhydrophilic surfaces, which may be of interest for improving cell adhesion on the peri-implant surface. In this article, we address the influence of this type of surface treatment on type IV and type V titanium discs on their surface energy and cell growth on them. Materials and methods: Samples from titanium rods used for making dental implants were used. There were two types of samples: grade IV and grade V. In turn, within each grade, two types of samples were differentiated: untreated and treated with sand blasting and subjected to double acid etching. Synthesis of the film consisting of titanium oxide pillar array structures was carried out using plasma-enhanced chemical vapor deposition equipment. The plasma was generated in a quartz vessel by an external SLAN-1 microwave source with a frequency of 2.45 GHz. Five specimens from each group were used (40 discs in total). On the surfaces to be studied, the following determinations were carried out: (a) X-ray photoelectron spectroscopy, (b) scanning electron microscopy, (c) energy dispersive X-ray spectroscopy, (d) profilometry, (e) contact angle measurement or surface wettability, (f) progression of contact angle on applying ultraviolet irradiation, and (g) a biocompatibility test and cytotoxicity with cell cultures. Results: The application of ultraviolet light decreased the hydrophobicity of all the surfaces studied, although it did so to a greater extent on the surfaces with the studied modification applied, this being more evident in samples manufactured in grade V titanium. In samples made in grade IV titanium, this difference was less evident, and even in the sample manufactured with grade IV and SLA treatment, the application of the nanometric modification of the surface made the surface optically less active. Regarding cell growth, all the surfaces studied, grouped in relation to the presence or not of the nanometric treatment, showed similar growth. Conclusions. Treatment of titanium oxide surfaces with ultraviolet irradiation made them change temporarily into superhydrophilic ones, which confirms that their biocompatibility could be improved in this way, or at least be maintained. [ABSTRACT FROM AUTHOR]

Four polymer and ceramic computer-aided design/computer-aided manufacturing (CAD/CAM) materials from different manufacturers (VITA CAD-Temp (polymethyl methacrylate, PMMA), Celtra Duo (zirconia-reinforced lithium silicate ceramic, ZLS), IPS e.max CAD (lithium disilicate (LS2)), and VITA YZ (yttrium-tetragonal zirconia polycrystal, Y-TZP)) were tested to evaluate the cytotoxic effects and collagen type I secretions on human gingival fibroblasts (HGFs). A total of 160 disc-shaped samples (Ø: 10 ± 2 mm; h: 2 mm) were milled from commercial blanks and blocks. Direct-contact cytotoxicity assays were evaluated at 24, 48, and 72 h, and collagen type I (COL1) secretions were analysed by cell-based ELISA at 24 and 72 h. Both experiments revealed statistically significant differences (p < 0.05). At 24 and 48 h of contact, cytotoxic potential was observed for all materials. Later, at 72 h, all groups reached biologically acceptable levels. LS2 showed the best results regarding cell viability and collagen secretion in all of the time evaluations, while Y-TZP and ZLS revealed intermediate results, and PMMA exhibited the lowest values in both experiments. At 72 h, all groups showed sharp decreases in COL1 secretion regarding the 24-h values. According to the results obtained and the limitations of the present in vitro study, it may be concluded that the ceramic materials revealed a better cell response than the polymers. Nevertheless, further studies are needed to consolidate these findings and thus extrapolate the results into clinical practice. [ABSTRACT FROM AUTHOR]

(1) Background. Titanium is characterized by its biocompatibility and resistance to stress and fatigue. Treatment with argon plasma may favour growth of human osteoblasts with respect to cell adhesion and proliferation. The aim of this study was to analyse the behaviour of human osteoblasts (MG-63) on Grade IV and V titanium possessing a sand-blasted, acid-etched (SLA) surface. SLA is a widely used surface treatment to create micro- and macroretentions to enhance osteoconductive properties on the surface. (2) Methods. One group of each grade of titanium was decontaminated with argon plasma and compared. On each disc, 20 × 104 cells were cultivated for morphological analysis, study of cell viability (regarding a negative control [100% viability]) and mitochondrial energy balance. (3) Results. At 24 h titanium treated with SLA showed a higher percentage of cell viability (47.3 ± 8.1%) compared to titanium IV treated with argon plasma, which presented a percentage of 79.1 ± 1.1%. Grade V titanium treated with argon plasma presented a higher viability percentage 91.3 ± 3.0% whereas nontreated Grade V titanium presented 53.3 ± 4.0%. Cells cultivated on the surfaces with an argon-plasma treatment were enlarged in comparison to non-treated discs. The cells with smaller circularity with a greater spread and spindle shape were the ones cultivated on the Grade V titanium surface. Cells seeded on treated titanium IV and titanium V, treated or not, showed higher mitochondrial activity over nontreated titanium IV. (4) Conclusions. Cells cultivated on those Grade V titanium discs that were decontaminated with argon plasma presented higher levels of cell adhesion and proliferation, lower mitochondrial damage and a higher mean cell area compared to those not decontaminated with argon plasma. [ABSTRACT FROM AUTHOR]

Polymethyl methacrylate (PMMA) and lithium disilicate are widely used materials in the dental field. PMMA is mainly used for the manufacture of removable prostheses; however, with the incorporation of CAD-CAM technology, new applications have been introduced for this material, including as a provisional implant attachment. Lithium disilicate is considered the gold standard for definitive attachment material. On the other hand, PMMA has begun to be used in clinics as a provisional attachment until the placement of a definitive one occurs. Although there are clinical studies regarding its use, there are few studies on cell reorganization around this type of material. This is why we carried out an in vitro comparative study using discs of both materials in which human gingival fibroblasts (HGFs) were cultured. After processing them, we analyzed various cellular parameters (cell count, cytoskeleton length, core size and coverage area). We analyzed the surface of the discs together with their composition. The results obtained were mostly not statistically significant, which shows that the qualities of PMMA make it a suitable material as an implant attachment. [ABSTRACT FROM AUTHOR]

New zirconia-reinforced lithium silicate ceramics (ZLS) could be a viable alternative to zirconium (Y-TZP) in the manufacture of implantological abutments—especially in aesthetic cases—due to its good mechanical, optical, and biocompatibility properties. Although there are several studies on the ZLS mechanical properties, there are no studies regarding proliferation, spreading, or cytomorphometry. We designed the present study which compares the surface, cellular proliferation, and cellular morphology between Y-TZP (Vita YZ® T [Vita Zahnfabrik (Postfach, Germany)]) and ZLS (Celtra® Duo [Degudent (Hanau-Wolfgang, Germany)]). The surface characterization was performed with energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and optical profilometry. Human gingival fibroblasts (HGFs) were subsequently cultured on both materials and early cellular response and cell morphology were compared through nuclear and cytoskeletal measurement parameters using confocal microscopy. The results showed greater proliferation and spreading on the surface of Y-TZP. This could indicate that Y-TZP continues to be a gold standard in terms of transgingival implant material: Nevertheless, more in vitro and in vivo research is necessary to confirm the results obtained in this study. [ABSTRACT FROM AUTHOR]