Environmental sustainability related to dental materials and procedures in prosthodontics: A critical review.

This article aims to review the status, challenges, and directions of environmentally sustainable oral healthcare by focusing on the dental materials and procedures used in prosthodontics. Sustainable development is a global priority and requires a systemic, integrative approach from all sectors of society. The oral healthcare sector is responsible for substantial greenhouse emissions throughout its value chain, including raw material extraction, industrial production, supply distribution, clinical practice, and management of waste. Of all dental specialties, prosthodontics has been one of the main generators of carbon emissions by fabricating a single product such as dentures or crowns in multiple steps. Dental prosthetic procedures involve chemicals and materials such as polymers, ceramics, metals, gypsum, and wax, which are often used in large quantities and for a single use. Thus, environmental risks and socioeconomic burdens can result from residuals and improper disposal, as well as waste and the embedded costs of unused materials retained by manufacturers, retail suppliers, dental laboratories, and dental clinics. To mitigate the environmental impact generated by conventional prosthodontics, we urge awareness and the adoption of sustainable good practices in the daily routine of dental clinics and laboratories. Capacity building and investment in a circular economy and digital technology can reduce the carbon footprint of prosthetic dentistry and improve the quality of life for present and future generations.

Effect of hyaluronic acid on paracrine signaling of osteoblasts from mesenchymal stromal cells: potential impact on bone regeneration.

OBJECTIVES: This study evaluated hyaluronic acids (HA) with different molecular weights as potential matrices for tissue-engineered bone grafting and their possible influence on the paracrine mechanisms of adipose-derived mesenchymal stromal cells. MATERIAL AND METHODS: Murine adipose mesenchymal stromal cells (mASCs) on the fourth passage were seeded in 96-well plates, osteoinduced for 27 days and exposed for 3 days to low (HA-LW) and high/low molecular weight (HA-HLW) at previously defined concentrations. Cytokines IGF-1, VEGF, FGF-2, and BMP-2 were evaluated by quantification in the supernatant. RESULTS: Greater expression of growth factors was observed in groups with HA-HLW compared to HA-LW. Results indicated that differentiated cells secreted fewer cytokines, namely VEGF, FGF, and BMP-2 than undifferentiated mASCs (p < 0.05). IGF-1 showed its greatest expression in the mASC HA-LW group (p < 0.05). CONCLUSIONS: The application of HA-HLW as cell matrix in tissue engineering did not compromise mASC paracrine effect. Also, the association of HA-HLW matrix and mASCs resulted in greater expression of osteogenic growth factors. Longer periods of cell differentiation seemed to negatively affect their capacity for local paracrine stimulation. CLINICAL RELEVANCE: The use of HA-HLW as matrix for undifferentiated ASCs can be positive for bone regeneration, favoring its application as cell matrix in bone grafting procedures.

The influence of dental implants in periapical and panoramic radiographs and cone beam computed tomography images: a clinical study.

The aim of this study was to analyze the influence of dental implants on the radiographic density of the peri-implant region in tomographic and radiographic examinations. A sample of 21 dental implants from 10 patients with Brånemark-protocol prostheses was evaluated based on postoperative control images, including periapical radiography (paralleling technique), panoramic radiography, and cone beam computed tomography (CBCT). The density means of 6 defined areas near dental implants were calculated and compared considering their locations and the different imaging examinations. The CBCT examinations showed significantly different densities among the measured areas (P < 0.001), while there were no significant differences among the density means of the various areas in periapical radiographs (P = 0.430) and panoramic radiographs (P = 0.149). The highest mean densities were observed in areas closer to the implants in all the examinations: CBCT (127.88 and 120.71), panoramic (106.51 and 106.09), and periapical (120.32). The sagittal CBCT images were measured in 2 different sections, and in both sections those areas closer to implants showed mean densities that were significantly higher than means from more distant areas (P < 0.001). Means from distant areas on CBCT slice imaging were significantly lower than the densities of the same areas on periapical and panoramic examinations. The changes in mean radiographic density values in the peri-implant region confirmed the interference of dental implants in radiographic and tomographic images. CBCT images suffered the greatest interference from dental implants.

Characterization of the interface between cast-to Co-Cr implant cylinders and cast Co-Cr alloys.

STATEMENT OF PROBLEM: The affordable Co-Cr cast alloy should provide an ideal interface with prefabricated cast-to cylinders from the same alloy family. The alloy microstructures should be maintained up to the interface, and porosities and reaction regions should be absent, and sufficient bond strength between alloys should be provided. PURPOSE: The purpose of this in vitro study was to evaluate the metallurgical interfacial compatibility between Co-Cr dental casting alloys and a prefabricated Co-Cr dental implant cast-to-cylinder. MATERIAL AND METHODS: A Co-Cr alloy was cast to Co-Cr implant cylinders. Specimens were cross-sectioned longitudinally and divided into as-cast and heat-treated groups. The microstructures of specimens were evaluated by optical and scanning electron microscopy. The elemental composition of as-received prefabricated implant cylinders and diffusion characteristics of cast interfacial regions were determined by energy dispersive x-ray spectroscopy. Vickers hardness values were defined across the interface on cast specimens and for the as-received implant cylinders. ANOVA and Tukey honest significant differences tests were used for the statistical evaluation of hardness values. RESULTS: No significant reaction regions or porosity were present in the interface. Microstructural aspect and interdiffusion indicated a metal-metal bond between the Co-Cr implant cylinder and cast alloy. Mean hardness values demonstrated a significant rise across the interface (373.5 ±12.8; 363.8 ±12.6, respectively) from the wrought cylinder (338.6 ±10.5; 329 ±9.7, respectively) to the cast alloy (399.8 ±7.4; 392.3 ±10.3, respectively) for the as-cast and heat-treated conditions, respectively. CONCLUSIONS: Co-Cr casting alloy cast on to prefabricated Co-Cr implant cylinders provided interfaces which appear to fulfill the requirements of the established criteria.

Stress on implant-supported fixed prostheses with different numbers of abutments after the application of acrylic resin.

STATEMENT OF PROBLEM: Clinical procedures and laboratory processing techniques inevitably induce stress in the implant/abutment/prosthesis system and may have negative effects when different numbers of implants are used. PURPOSE: The purpose of the study was to evaluate the tension on the abutments of implant-supported fixed prostheses and to determine the effect of the application of an esthetic veneer (acrylic resin) and the number of abutments (5 or 4). MATERIAL AND METHODS: Four palladium-silver alloy cast bars were fabricated to simulate implant-supported fixed complete prostheses. Strain gauges were fixed on the abutments to measure the tension before and after the application of the esthetic veneer. The values of tension were measured in models with 5 or 4 abutments. Data were analyzed with a repeated measures ANOVA. RESULTS: No statistically significant differences were found for the main factors (esthetic veneer, P=.22; number of abutments, P=.14) despite the large effect size. CONCLUSIONS: The results of this study suggest that the tension in the abutments of an implant-supported fixed prosthesis is not affected by the application of acrylic resin veneering or by reducing the number of abutments.

Maxillary rehabilitation using a removable partial denture with attachments in a cleft lip and palate patient: a clinical report.

Clefts of the lip and/or palate (CLP) are oral-facial defects that affect health and overall quality of life. CLP patients often need multidisciplinary treatment to restore oral function and esthetics. This paper describes the oral rehabilitation of a CLP adult patient who had maxillary bone and tooth loss, resulting in decreased occlusal vertical dimension. Functional and cosmetic rehabilitation was achieved using a maxillary removable partial denture (RPD) attached to telescopic crowns. Attachment-retained RPDs may be a cost-effective alternative for oral rehabilitation in challenging cases with substantial loss of oral tissues, especially when treatment with fixed dental prostheses and/or dental implants is not possible.

Meta-analysis of single crowns supported by short (<10 mm) implants in the posterior region.

AIM: To assess the failures and complications of short (<10 mm) implants supporting single crowns in the posterior region and its potential risk factors (RkF). MATERIALS AND METHODS: Prospective studies were screened according to eligibility criteria, followed by contact with authors. Quality assessment was performed using a standardized protocol. Mean implant failure proportion (FP), biological and prosthetic failure proportions (BFP/PFP) and marginal bone loss (MBL) including 95% confidence intervals were estimated using random-effects models for meta-analysis. RESULTS: Sixteen studies with a medium methodological quality (mean score: 8 ± 3; 2-14) had data collected. In summary, 762 short implants were followed up for up to 120 months in 360 patients (mean follow-up: 44 ± 33.72 months; mean dropout rate: 5.1%). The means FP, BFP, PFP and MBL were 5.9% (95%CI: 3.7-9.2%), 3.8% (95%CI: 1.9-7.4%), 2.8% (95%CI: 1.4-5.7%) and 0.83 mm (95%CI: 0.54-1.12 mm) respectively. Quantitative analysis showed that placement in the mandible (p = 0.0002) and implants with length ≤8 mm (p = 0.01) increased FP, BFP and MBL, whereas qualitative assessment revealed that crown-to-implant ratio did not influence MBL. CONCLUSIONS: Single crowns supported by short implants in the posterior region are a predictable treatment option with reduced failure rates, biological/prosthetic complications and minimal bone loss.

Importance of phytotherapy for oral health care and quality of life in adults: A scoping review.

Medicinal plants and herbal medicines are used as integrative and complementary practices to provide comprehensive care, disease prevention, health promotion, and to improve quality of life (QoL). This scoping review aimed to identify and describe the use of phytotherapy in oral health care by adults and their outcomes, with a focus on perceptions of oral health-related QoL, healthcare access, and costs. A systematic search was conducted in six databases and supplemented in grey literature. According to a PRISMA-ScR protocol and eligibility criteria, publications were assessed for final inclusion, data charting, and narrative synthesis. Out of 4124 records, 542 publications were selected for full-text reading. A total of 32 studies were included: 21 studies assessed QoL, 7 reported access issues, and 11 reported costs issues. Herbal mouthwashes to prevent or treat non-infectious oral conditions were the most frequent treatment. Efficacy of phytotherapy was usually better than placebo or control treatment. Most studies reported QoL improvement, but several instruments were used with heterogeneous results. Limited healthcare access and high costs favoured traditional folk herbal medicine in underserved populations. It can be concluded that phytotherapy for oral health is used by adults worldwide, following modern clinical pharmacology and traditional knowledge concepts. Further studies should incorporate assessment of QoL, access, and costs in addition to clinical efficacy and safety, which are complementary aspects for delivering a comprehensive and efficient health care for all people.

Adverse Effects of Natural Products in the Oral Mucosa and Face: A Scoping Review.

Objective: This scoping review aimed to map the adverse reactions in the oral mucosa and face caused by the use of natural products. Methodology: This review was performed according to the Joanna Briggs Institute Manual for Evidence Synthesis and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines, with a protocol registered in the Open Science Framework (DOI 10.17605/OSF.IO/R57D8). The search was carried out systematically using PubMed, Scopus, Web of Science, Embase, LILACS, and LIVIVO databases, as well as gray literature through Google Scholar and OpenGrey. Reports of clinical cases on the adverse effects of natural products on the oral mucosa or perioral region of the face resulted from inappropriate use or self-medication were included. Data from the included studies were described in a narrative form. Results: Seven hundred and six studies were identified, and after removing duplicates and applying the eligibility criteria, 28 studies were included. The year of publication ranged from 1976 to 2022. The studies were conducted in 19 countries. Fifty patients were mentioned in the included studies and 34 were female (68%). The natural products most related to adverse reactions were propolis (n = 17), with manifestations such as perioral eczema, edema, erosions, erythema, allergic contact dermatitis, and garlic (n = 9), with manifestations such as chemical burn, burning sensation, vesicles and blisters, crusts, and ulcerations. Conclusion: Propolis and garlic were the natural products with the most reported adverse effects on the oral mucosa and perioral region.

Long-term clinical performance of short 6-mm implants supporting single crowns in the posterior region: A 10-year cohort study.

INTRODUCTION: Long-term clinical success of non-splinted, posterior, and short implants still is unclear. This prospective cohort study reports the 10-year follow-up of 6-mm implants supporting single crowns in the posterior region, and patient-reported outcomes. METHODS: Baseline sample comprised 20 patients treated with 46 screw-retained crowns supported by 6-mm implants with moderately rough implant surface. Participants were recalled for a 10-year clinical follow-up to assess survival rates, biologic and mechanic conditions, quality of life (OHIP-14), and treatment satisfaction. Data were collected with clinical-radiographic exams and analyzed using descriptive and inferential statistics. RESULTS: Fourteen patients with 35 implant-crown units were examined after 127.6 ± 11.8 months. For the entire cohort period, 7/46 implants were lost (survival estimate: 77.7% at 133 months), and mechanic complications occurred in 14/46 units (survival estimate: 66.4% at 116 months). In the Cox models, "maximum occlusal force" had a significant effect for implant loss (p = 0.038) and for prosthetic screw loosening (p = 0.038); "arch" and "bruxism" were not significant. Peri-implant bone loss was 0.4 ± 0.6 mm at 10 years. For peri-implant bone level, "crown-to-implant ratio" (p < 0.001) and "time" (p = 0.001) were significant. Bone levels differed from baseline to 12, 48, and 120 months. Satisfaction VAS was 94.0 ± 7.9 mm and OHIP-14 was 2.3 ± 2.2. CONCLUSION: Single screw-retained crowns supported by 6-mm implants have an acceptable long-term clinical performance, with stable peri-implant bone levels after 10 years of function.

Cell culture-based tissue engineering as an alternative to bone grafts in implant dentistry: a literature review.

Several biomaterials and techniques for bone grafting have been described in the literature for atresic bone tissue replacement caused by edentulism, surgical resectioning, and traumas. A new technique involves tissue engineering, a promising option to replace bone tissue and solve problems associated with morbidity of autogenous grafting. This literature review aims to describe tissue-engineering techniques using ex vivo cell culture as an alternative to repair bone maxillary atresias and discuss the concepts and potentials of bone regeneration through cell culture techniques as an option for restorative maxillofacial surgery.

A within-subject comparison of short implants in the posterior region: retrospective study of up to 10 years.

PURPOSE: This intra-patient retrospective study of up to 10 years evaluated the clinical success and risk factors of 6- and 8-mm long implants and their respective prostheses. MATERIALS AND METHODS: The sample consisted of patients treated at a Military Polyclinic dental service, who received both 6- and 8-mm long tissue level implants in the posterior region of the same arch. Data were collected from the dental charts, clinical and radiographic exams, self-report of sleep bruxism, measurement of maximum occlusal force, and clinical crown-to-implant (C/I) ratio. Data were analyzed by descriptive and inferential statistics with univariate and hierarchical multivariate models, at the 0.05 significance level. RESULTS: The 30 patients (27 women) had 85 implants and 83 prostheses. Two implants were lost before prosthesis installation (implant survival: 97.6%). Ten events of prosthetic complication (screw tightening loss) occurred in five patients (success rate: 87.9%) in a single moment. Only the variable C/I ratio had a significant effect for repairable prosthesis complication (P<.05). CONCLUSION: The results suggest that 6- and 8-mm long implants have similar long-term clinical success for implants and prostheses.

Case report of oral mucosa garlic burn during COVID-19 pandemic outbreak and role of teledentistry to manage oral health in an older adult woman.

BACKGROUND: The COVID-19 global pandemic and the uncertainty of an effective treatment protocol have resulted in fear and anxiety, which have increased the search for natural products to prevent the disease and to manage the symptoms. AIMS: To discuss the negative effects of garlic used as a preventive measure against the novel coronavirus. METHODS AND RESULTS: This study reports a case of oral mucosa burn on the dorsal surface of the tongue in a 72-year-old woman. The patient was using raw garlic daily during the pandemic to improve her immunological system. She scheduled a dental appointment and was assessed by teledentistry due to the pandemic, in which a detailed anamnesis was carried out. The burned area and ulceration were identified by video call and photographs. The patient was instructed to cease the habit immediately and change to a soft and non-acid/spicy/hot diet, which resulted in a great recovery 2 days later. She was monitored for 2 weeks until her tongue was completely healed. CONCLUSION: This case highlights the consequences of inappropriate use of natural product and how self-treatment could negatively influence oral health. Additionally, it shows the importance of teledentistry for oral diagnosis and treatment during a pandemic.

Effect of surface topography of implant abutments on retention of cemented single-tooth crowns.

This study investigated whether surface topography affects the retentive strength of cemented full crowns, comparing the effects of standard machined, sandblasted, and grooved implant abutments. Five metallic crowns per abutment type were cast and cemented with zinc phosphate. After 24 hours, the specimens were submitted to a tensile test. The retentive strength of the cemented crowns was affected by abutment surface topography. The sandblasted and grooved surface groups had approximately 2.4 times greater mean uniaxial retentive strength than the machined surface group (P < .001). The retentive strength of the sandblasted and grooved abutments was similar, despite marked differences in surface profiles and roughness parameters.

Initial enamel wear of glazed and polished leucite-based porcelains with different fusing temperatures.

This study used the radiotracer method to measure the initial enamel wear caused by low- and high-fusing porcelains after glazing or polishing. It also tested the correlation between enamel wear and porcelain surface roughness (Ra). Surface morphology was assessed by optical microscopy. Cylindrical specimens of three porcelains (two high-fusing, one low-fusing) were either autoglazed or polished. Flattened enamel specimens were irradiated with neutrons and submitted to the wear assay for 2,500 cycles in distilled water using a 285 g load; the released beta 32P particles were measured for 10 minutes. For all samples, Ra was recorded with a profilometer before and after testing. Enamel wear was not significantly different for porcelain or finishing method but there was a trend of interaction between the two variables (p = 0.08). A positive correlation was found between enamel wear and the initial Ra of porcelain (r = 0.71). The glazed surfaces of high-fusing porcelains were wavy and had a greater Ra, while the polished surfaces had grooves and pores prior to wear testing. The low-fusing porcelain demonstrated lower Ra and a more homogeneous surface. All abraded surfaces had similar morphology after the wear assay.

Relation between insertion torque and tactile, visual, and rescaled gray value measures of bone quality: a cross-sectional clinical study with short implants.

BACKGROUND: This study assessed the relationship between insertion torque and bone quality evaluated during surgery and in preoperative computed tomographic (CT) images analyzed either visually or by rescaled mean gray values (MGVs). The study also tested the correlation between the clinical and radiographic measures of bone quality. METHODS: The consecutive sample was composed of 45 short implants (4.1 × 6 mm) placed in the posterior region of 20 patients. Intra-surgical tactile bone quality, based on the classification of bone types by Lekholm and Zarb, and insertion torque were recorded during the implant placement. Visual bone quality and normalized MGV were assessed in standardized axial, coronal, and sagittal sections of preoperative CT images. Data were analyzed by ANOVA and Spearman correlation (alpha = 0.05). RESULTS: Insertion torque was associated with all assessment methods of bone quality (tactile, CT visual, MGV). A moderate correlation was found among all methods of bone quality, except for CT visual assessment and tactile evaluation. MGVs varied as a function of arch, dental region, insertion torque, and bone types. CONCLUSIONS: The results suggest that bone quality measures affect primary stability as recorded by insertion torque, and the assessment methods are consistently related.

Analysis of the Marginal Fit and Dimensional Stability of Cast-to Cobalt-Chromium Implant Cylinders Cast from Different Alloys.

PURPOSE: To evaluate the influence of cobalt-chromium (Co-Cr) casting alloys' melting temperatures on the cast-to Co-Cr implant cylinders' marginal fit. MATERIALS AND METHODS: Co-Cr alloys with different melting ranges were cast into 20 Co-Cr cylinders: 10 in a high-melting temperature (HMT) group and 10 in a low-melting temperature (LMT) group. Ten cylinders were used as received as a control group. Cylinders' marginal misfit and dimensional stability were evaluated using scanning electron microscopy (×500). RESULTS AND CONCLUSION: HMT cylinders showed significant differences in marginal misfit (2.48 ± 1.07 µm2) compared to LMT (1.53 ± 0.37 µm2) and control (1.27 ± 0.57 µm2) cylinders, but there were no differences in dimensional stability. HMT Co-Cr alloys produce implant-supported prostheses with poor marginal fit.

Volumetric Bone Measurement Around Dental Implants Using 3D Image Superimposition: A Methodological and Clinical Pilot Study.

PURPOSE: This study describes the development of a methodology for using three-dimensional (3D) image superimposition to measure volumetric changes in bone level around dental implants in comparison with linear measures. MATERIALS AND METHODS: The sample was comprised of 46 dental implants of 6-mm length and 4.1-mm diameter placed in the posterior maxilla and posterior mandible in 20 patients. All implants received screw-retained single crowns. Radiographic images were taken using cone beam computed tomography (CBCT) and digital periapical radiography after implantation and after 12 and 24 months of functional loading (after crown installation). Tridimensional reconstructions of the bone perimeter closest to the implant were developed, superimposed, and volumetrically measured. Linear measures of bone levels were recorded in periapical radiography images. A multilevel regression model tested volumetric and linear bone loss. RESULTS: The mean peri-implant linear bone loss for the first and second years was 0.2 ± 0.4 mm and 0.1 ± 0.2 mm, respectively, and the mean volumetric bone loss for the first and second years was 7.2 ± 6.1 mm³ and 6.4 ± 7.8 mm³, respectively. It was estimated that an increase of 1 mm of linear bone loss was associated with a mean volumetric bone loss of approximately 14 mm³ (P < .001). CONCLUSION: The findings showed that linear and volumetric bone loss measures are related. Measuring volumetric bone changes around implants is possible provided that the CBCT images have proper contrast and sharpness, particularly around the implant outline. Improvements in image quality and in the filters for bone tissue detection would be important for this methodology to be made faster and used clinically.

Quality of life and mastication in denture wearers and cleft lip and palate adults.

The impact of oral rehabilitation on masticatory function and oral health-related quality of life (OHRQoL) may vary with the experience of the individual with tissue loss. Our hypothesis is that patient-centered outcomes vary among adults who have experienced large defects in the maxilla due to congenital or acquired conditions even after oral rehabilitation to restore aesthetics and function. This study compared OHRQoL, perceived masticatory ability, maximum bite force (MBF), and symptoms of pain and depression among subjects with acquired (edentulous maxilla) and congenital (cleft lip and palate) loss of oral tissues in the maxilla after dental treatment. A gender-matched sample (n = 60) of cleft lip and palate (CLP), maxillary denture wearers (DENT) and controls (CONT) was recruited. OHRQoL was assessed using OHIP-14. Chewing was evaluated through a masticatory ability questionnaire and by MBF. The RDC/TMD Axis II questionnaire was used to assess symptoms of pain and depression. Data were analyzed by Fisher's test, Kruskal Wallis test, and Spearman correlation coefficients. CLP showed higher OHIP-14 and depression scores than DENT and CONT (p < 0.05). Sub-analysis by OHIP-14 items (%FOVO) showed higher prevalence of psychological impact for CLP and of functional impacts for DENT. The number of foods difficult to chew, of food textures difficult to chew, and avoided foods were similar between CLP and DENT. OHIP-14, MBF, and depression scores showed significant correlation (p < 0.05). The results suggest that adults with treated CLP or maxillary DENT have chewing impairment and lower MBF than healthy subjects, with different psychological and functional impacts.