Extensive Caries Research Articles

Clinical and Radiographic Assessments of Potassium Nitrate in Polycarboxylate Versus Mineral Trioxide Aggregate as Pulpotomy Biomaterials in Immature Mandibular First Permanent Molars: A Randomized Clinical Trial

IntroductionThe purpose of this study was to compare clinically and radiographically the effects of potassium nitrate in polycarboxylate cement and mineral trioxide aggregate (MTA) as pulpotomy agents in vital immature mandibular first molars. MethodsThe trial design was a parallel randomized, 1:1 allocation ratio, with both the participants and the data assessor blinded. A total of 50 molars of 48 eligible children aged 6–9 years were studied. The children had mandibular immature first molars with extensive caries that revealed pulp exposure during caries excavation. Patients were randomly allocated equally into 2 groups in which potassium nitrate in polycarboxylate cement (the intervention group) and MTA (the control group) were used as pulpotomy biomaterials. The treated teeth were restored permanently. The primary outcome was clinical/radiographic assessment after 1 week, 6 months, and 12 months. The secondary outcomes were radiometric analysis at 6 and 12 months to determine dimensional changes during maturogenesis. The digital radiographs were imported to image processing software to perform radiometric measurements. Data were tabulated and statistically analyzed with significance set at P ≤ .05. ResultsOnly a single tooth failed at the 6-month recall, and another one was lost during recall in each group. Thus, the overall success rate for cases/group who finally attended the 12-month follow-up time point was 92% (23/25) with no statistically significant difference between the 2 groups. At the 12-month recall, successful cases showed root development with an increase in root length and a decrease in apical foramen width. Complete apical closure was observed in 65.2% of the roots in the intervention group and 52.1% in the control group. ConclusionsThe clinical and radiographic success reported in the present study reveals that potassium nitrate in polycarboxylate cement could be used as a biological and economic alternative to MTA as a pulpotomy agent in vital immature mandibular first molars. Further follow-up for longer periods is recommended.

Crown Lengthening Surgery for Enhancing Restorative Treatment in Esthetic Zone

For obtaining adequate retention for restoring cases like subgingival caries or extensive caries that shortens the tooth, short clinical crown, and fractures, it is usually necessary to disclose more tooth structure. Crown lengthening procedure is done to increase the clinical crown length for restorative or esthetic reasons without breaching the biologic width. These procedures are also utilized to improve the appearance and retention of restorations placed within the esthetic zone. We report a case of crown lengthening surgery with an internal bevel gingivectomy which was done in our department without compromising tooth support and esthetics.

In Vitro Fracture Resistance of Permanent Molars with Undermined Walls Restored With Different Materials and Techniques

Introduction: Restoration of freshly erupted permanent first molars with extensive caries is a challenge in pediatric dentistry. This study aimed to compare the fracture resistance of permanent molars with undermined walls restored with amalgam and composite resin along with cusp reduction, reinforcement of the walls with glass ionomer (GI) or no further intervention. Methods: This experimental in-vitro study evaluated 72 freshly extracted sound human third molars with almost equal dimensions. After cavity preparation, the teeth were then randomly divided into three groups. In group 1, the undermined area was reinforced with light-cure GI. Group 2 received a 2 mm cuspal cap, and group 3 received no intervention. Half of the teeth in each group were restored with composite resin and the other half with amalgam. The teeth then underwent thermocycling and their fracture resistance was measured by a universal testing machine. Data were analyzed using two-way ANOVA. Results: No significant difference was noted in fracture resistance among three procedures in teeth restored with composite (P=0.589). However, this difference was significant in teeth restored with amalgam (P=0.001). Conclusion: The current results indicated when esthetics is not a priority, applying amalgam restorations with GI-reinforced undermined walls might be suitable for restoration of freshly erupted permanent first molars with extensive caries.

Multipotent stem cells from apical pulp of human deciduous teeth with immature apex

Isolation of high-quality human postnatal stem cells from accessible sources is an important goal for dental tissue engineering. Stem cells from developing organs are a better cell source but are hard to obtain. With extensive caries that are difficult to restore, the extracted deciduous tooth with an immature apex is a developing organ for investigation. In the present study, a cell population from the tip of apical pulp of human deciduous teeth with an immature apex was isolated and termed apical pulp-derived cells of deciduous teeth (De-APDCs). De-APDCs expressed STRO-1, CD44, CD90 and CD105 but not CD34 or CD45. Furthermore, De-APDCs demonstrated a significantly higher clonogenic and proliferative ability and osteo/dentinogenic differentiation capacity than dental pulp cells from exfoliated deciduous teeth (De-DPCs) (P < 0.05). Differentiation potential toward adipogenic, neurogenic and chondrogenic lineages was also observed in induced De-APDCs. In addition, after De-APDCs were seeded into hydroxyapatite/tricalcium phosphate (HA/TCP) scaffolds and transplanted into nude mice, they were able to regenerate dentin/pulp-like structures aligned with human odontoblast-like cells. In conclusion, De-APDCs, which are derived from a developing tissue, represent an accessible and prospective cell source for tooth regeneration.

Influencing Factors in Autotransplantation of Teeth with Open Apex: A Review of the Literature

Dental autotransplantation is the process by which a tooth located in its natural socket is extracted and relocated to another socket in which the tooth is missing or has been extracted due to various reasons such as trauma, extensive caries or periapical pathology, among other reasons. This proposed technique offers a more conservative alternative for patients in comparison with prosthetic or implant techniques, especially in young patients where implants are contraindicated until their maxillary bone system’s growth ends. Thus, the objective of this review was to present a qualitative synthesis of the risk factors that influence the results of open apex dental autotransplantation in humans. After confirming that there are various factors that influence dental autotransplantation, it was concluded that the extra-alveolar time of the donor tooth and the periodontal damage of the root of the donor tooth are the factors of greatest interest in the literature, both closely linked to the use of 3D replication of the transplanted tooth.

Nickel Sensitivity in Children Due to Using Stainless Steel Crowns: A Narrative Review

Context: Stainless Steel Crowns (SSC) are stable and durable restorations and a valuable technique in repairing deciduous teeth with extensive caries. Nickel and chromium are the main composing elements of SSCs, i.e. released in the oral environment; they can cause allergic reactions, especially in nickel-sensitive children. The symptoms of these reactions include gingival edema and the loss of alveolar bone. Evidence Acquisition: The required data used in our review were searched from articles published until 2020 and collected from online databases, including Scopus, PubMed, Google Scholar, and Science Direct, using “Nickel, Allergy, and SSCs” keywords. Articles concerning SSCs and their application, nickel allergy released from crowns, and their symptoms were included in this study. After the abstract screening, we recalled relevant studies for full-text review. Results: We are exposed to nickel every day in various forms; some individuals present hypersensitivity reactions when exposed to the slightest amounts of this metal. Nickel is a base metal and among the elements used in SSCs. Nickel is released from SSCs during the corrosion process in the oral environment. Excessively released nickel ions cause chronic fatigue syndrome, sensitive lymph nodes, muscle aches, and headaches. Conclusions: The amount of nickel released from SSCs is less than the number of other sources; thus, the immunological reactions of a large percentage of the population to this excess amount of nickel ions in the bloodstream are normal and cause no severe problems.

SPECIAL CHILD CARE: WEST SYNDROME MANAGEMENT DURING COVID-19 PANDEMIC

West syndrome is a clinical condition characterized by the combination of an abnormal EEG showing chaotic pattern called hypsarrhythmia, infantile spasms, and delayed development or loss of acquired milestones. The oral manifestations of the conditions are wide and varied ranging from poor oral hygiene, bleeding gums, periodontitis, altered chronology and delayed eruption, high arched palate and extensive caries in multiple teeth. COVID-19 has affected the provision of dental care to all, especially special child care. Henceforth with an aim towards provision of treatment for reliving pain in needful patient, the oral health management was carried out keeping in mind the current pandemic scenario and practice restrictions.

Terminal dentition to functional esthetic full-mouth implant reconstruction: Evidence-based approach

Implant-supported fixed dental prosthesis is a well-accepted treatment option for edentulism. Loss of teeth due to extensive caries or severe periodontitis presents a challenge to the clinicians. Young age disability with either of these problems can further make full-mouth rehabilitation on implants a complex procedure. The outcome of implant surgery with periapical infections and periodontal inflammation is unpredictable and often delays the placement of dental implants. Here, we describe a case of full-mouth reconstruction with implant-supported prosthesis in a young individual who lost all her teeth due to extensive caries. The journey from terminal dentition to functional esthetic rehabilitation was uneventful.

Ridge augmentation of Class III ridge defect using piezosurgery with autogenous chin graft followed by implant placement: A 6 months follow-up interventional study

Background: Tooth loss occurs due to periodontal disease, extensive dental caries, and fracture of teeth after a dento-alveolar trauma, cyst and tumours of odontogenic and non-odontogenic origin. Following loss of teeth, alveolar ridge resorption becomes an unwanted but unavoidable consequence. In order to restore the lost bone and replace the teeth with implants, ridge augmentation procedures are done. The present study aimed at restoring the class III ridge defect using piezosurgery with autogenous block bone graft procured from mandibular symphysis region. Materials and methods: A total number of 10 healthy patients with Class III ridge defect in maxillary anterior teeth region were enrolled for the study. The donor and defect sites were pre-surgically analysed using Cone-Beam Computed Tomography (CBCT), preclinical models and ridge mapping.The implant site width and height were assessed intra-operatively during the surgery and at re-entry after 6 months. The autogenous block bone grafts were procured from mandibular chin region using piezo-electric device and placed at the recipient site. At the 6 months re-evaluation, both clinical and radiographic parameters were assessed using CBCT of the recipient site. Implants were placed at two-stages and followed-up up to 6 months. Results: Clinical measurements showed that the mean horizontal bone gain and vertical bone gain was noted to be 3.21±0.24 mm and 2.18±0.32 mm respectively, by the end of 6 months follow-up. No major complications were presented at the recipient as well as donor sites. Piezoelectric surgery provided clean, bloodless field during the procedure and minimal post-operative discomfort to the patients. Conclusion: The results of the present study suggests that, class III ridge defects can be successfully augmented using piezo-surgery using autogenous bone grafting from the mandibular symphysis region. Also, delayed implant placement may provide satisfactory functional and aesthetic outcomes on the long term. Keywords: Ridge augmentation; chin graft; Piezosurgery; dental implants

Panoramic Radiographic Analysis of Signs of Proximity to the Third Molar Roots of the Mandibular Canal in Yemen

Objectives: The objectives of this study were to assess the relationship between the third molar and the mandibular canal, to identify the radiographic markers most prevalent in predicting connectivity between these structures, and to associate these signs and proximity with the position of the third molar according to Bell, Gregory’s and Winter’s classifications. Subjects and methods: A retrospective cross-sectional study was conducted in the city of Sana’a on a sample of Yemeni patients in Ammar Dental Clinics who underwent panoramic radiography in the year 2019 until September 2020. The study consisted of panoramic radiographs of 597 patients with third molars with a total of 1017 third molars; the number of males was 216 (36.2%) and 381 females (63.8%). The panoramic radiographs were evaluated for proximity signs. Inclusion criteria were patients of both sexes who had at least a fully formed third molar of the mandible that was adjacent to the second molar. The radiographs were excluded if evidence of cystic, neoplastic, or extensive caries processes was detected. Seven radiological signs were used to determine if there was contact between the third molar and the mandibular canal. Results: A proximity to the mandibular canal was verified for 620 (61%) of 1017 third molars. The most frequent radiographic signs of proximity were darkened roots (315 teeth [31%]) and discontinuity of the mandibular canal (267 teeth [26.3%]). Third molar/mandibular canal proximity was found significantly more frequently in female patients and in patients aged 24 years and younger (P &lt; 0.001). The tooth positions most frequently associated with proximity between the third molar and the mandibular canal were position C (highest point of the third molar located at or below the cervical margin of the second molar) and the mesioangular position (long axis of the third molar angled mesially toward the second molar). Conclusions: The frequency of third molar/ mandibular canal proximity was greater in female patients and patients aged 24 years or younger. The most frequently observed signs of proximity were darkening of the roots and discontinuity of the mandibular canal. The tooth positions most frequently associated with proximity of the third molar to the mandibular canal were position C and the mesioangular position.

Recall intervals for oral health in primary care patients.

Recall intervals for oral health in primary care patients.

Autologous transplant third mandibular molar in post extraction socket. Case report

Dental transplantation is a surgical alternative, which consists of transplanting a tooth from one alveolus to another in the same patient, very useful when replacing lost dental organs in young patients, with a high success rate. Present advantages helpful for patients providing a vital, proprioceptive and excellent aesthetic rehabilitation, without altering adjacent teeth, additionally represents an alternative cheaper. The purpose of this case report is to show clinical sequence about surgical approach for dental autotransplantation from lower third molar on alveolus after extraction of right lower first molar, carried out without endodontic treatment. Female patient case of 15 years old with a diagnosis of extensive caries not restorable in 46 is presented. It is decided through an interdisciplinary board to carry out, treatment with an autologous transplant of right lower third molar in socket post-extraction of first lower molar from the same hemiarchate, post-surgical controls are performed for up to one year. Dental transplantation is an excellent treatment option when it comes to replacing missing teeth, since it offers multiple functional and aesthetic advantages, mainly in children and young adults.

Oral Health Status among Children with Repaired Esophageal Atresia.

Esophageal atresia (EA) is a congenital anomaly, presenting multifactorial etiology. Swallowing problems and gastroesophageal reflux disease may accompany EA, which have adverse effects on oral health. In this descriptive study, intraoral examination of the children with repaired EA and of the dental patients without systemic/chronic disease was performed. Dental caries, dental erosion, and halitosis status were evaluated using the International Caries Detection and Evaluation System II, and the Basic Erosive Wear Examination indices as well as the Halimeter, respectively. There were 19 (n = 12 male; n = 7 female) case subjects and 16 (n = 10 male; n = 6 female) control subjects whose age ranged between 14 and 72 months. Among cases, 15 children had dental caries (78.9%; initial caries n = 4, moderate caries n = 4, and extensive caries n = 7). Of the controls, 13 had dental caries (81.2%; initial caries n = 5, moderate caries n = 5, and extensive caries n = 3). Although the median scores of decayed, missing, filled teeth (dmft) and decayed, missing, filled surfaces (dmfs)-for primary dentition-were not statistically significantly different between two groups, both dmft and dmfs were found to be higher among the case subjects (p = 0.172 for dmft; p = 0.230 for dmfs). Furthermore, six children with repaired EA had dental abnormalities (in shape, number, or calcification) and six children with repaired EA had dental erosion. The Halimeter measurement was performed for five case children of whom three had oral malodor, and for seven control children of whom two had oral malodor. Regular dental counseling adopting the multidisciplinary team approach for patients with EA is necessary to ensure better general and oral health.

Treatment of class II malocclusion with bimaxillary dentoalveolar protrusion and compromised mandibular first molars through anchorage miniscrews (TADS)

Patients with dental Class II bialveolar protrusion are generally treated by extracting all four first premolars or two first and two second premolars, and retracting the anterior teeth. This case report describes the treatment of an adult female patient aged 21-year-old with bialveolar protrusion, a Class II canine and class II molar relationship along with lip protrusion. In this patient, the lower right and left mandibular first molar i.e., (3-6) and (4-6) had to be extracted due to extensive caries, also extraction was performed for maxillary 1st right and left bicuspids i.e., (1-4) and (2-4).Mini-implant (1.4 mm in diameter, 8 mm long) were placed in interradicular bone between the maxillary second bicuspids and first molars and mesial to mandibular second molar to allow en-masse retraction of upper and lower anterior teeth. Overall, miniscrews (TADs) can provide anchorage to produce a good facial profile in cases of dental Class II bialveolar protrusion with hopeless mandibular first molars.

Effect of silver diammine fluoride on micro-ecology of plaque from extensive caries of deciduous teeth - in vitro study

BackgroundThe mechanism of action of silver diammine fluoride (SDF) on plaque micro-ecology is seldom studied. This study investigated micro-ecological changes in dental plaque on extensive caries of deciduous teeth after topical SDF treatment.MethodsDeciduous teeth with extensive caries freshly removed from school children were collected in clinic. Unstimulated saliva collection and initial plaque sampling were done before tooth extraction, then each caries was topically treated with 38% SDF in vitro. After intervention, each tooth was stored respectively in artificial saliva at 37 °C. Repeated plaque collections were done at 24 h and 1 week post-intervention. Post-intervention micro-ecological changes including microbial diversity, microbial metabolism function as well as species correlations were analyzed and compared after pyrosequencing of the DNA from the plaque sample using Illumina MiSeq platform.ResultsAfter SDF application, microbial diversity decreased (P > 0.05), although not statistically significant. Microbial community composition post-intervention was noticeably different from that of supragingival and pre-intervention plaque as well as saliva. At 1 week post-intervention, the relative content of Pseudomonas, Fusobacterium and Pseudoramibacter were higher than before, while most of the other bacteria were reduced, although the changes were not statistically significant (P > 0.05). The inter-microbial associations became more complex, much more positive associations among survived bacteria were observed than negative ones. COG function classification diagram showed carbohydrate transportation and metabolic functions in the plaque were significantly reduced at 24 h and 1 week post-intervention.ConclusionsSDF has extensive antimicrobial effect on dental plaque, which may reduce carbohydrate metabolism in dental plaque and help promote new balance of the plaque flora.

Caries Prevalence and Severity in Immature Permanent First Molar Teeth in Sanliurfa City, Turkey Molar Teeth in Sanliurfa City, Turkey

The prevalence of dental caries, a major public health problem in high-income countries, is gradually increasing in many low- and middle-income countries. The aim of this study is to evaluate the prevalence and severity of caries in the immature permanent first molars (PFMs) of children aged 7–9 years. Methods: This work is a retrospective analysis of caries in immature PFMs as observed from the panoramic radiographs of patients aged 7–9 years who presented to the pediatric clinic. The mean number of decayed, missing, or filled teeth (DMFT) and caries severity of immature PFMs were assessed. Results: A total of 3,112 PFMs from 778 patients were included in the study; 51.2% of the patients had at least one carious PFM. When caries prevalence was stratified by age, prevalences of 41.2%, 51.6%, and 60.4% were observed for children aged 7, 8, and 9 years, respectively. The relationship between age and presence of caries was statistically significant (p<0.01). The ratio of teeth with extensive-stage caries relative to all PFMs was 10.5%. Conclusions: In this study, the prevalence of caries in the immature PFMs of children aged 7–9 years was 51.2%, and the mean DMFT was 1.19. The finding that approximately 10% of PFMs exhibit extensive caries within 2–3 years after eruption is a serious concern.

Association between dental caries risk indicators and various stages of caries in newly erupted permanent teeth

Background/Aim. Identification of caries risk indicators involved in the disease development is of great importance. The aim of this study was to assess the association between distinctive risk indicators and different stages of caries disease process in children. Methods. The cross-sectional study was conducted on a sample (n = 327) of school children ages 7?11. A questionnaire submitted to parents was used to record the data regarding demographic characteristics, children's dietary habits, oral hygiene habits and oral health behaviors. Caries was assessed using the International Caries Detection and Assessment System (ICDAS) II and subjects were stratified according to the highest and most prevalent caries lesion stage. The data obtained were analyzed using the ?2 or Fisher`s exact test and multinomial logistic regression. Results. Caries lesions were detected in 56.6% of examinees observed in the study. Compared to caries-free subjects, appearance of initial caries lesions was statistically significantly influenced by maternal education level (p = 0.021), paternal occupational status (p = 0.023), toothbrushing frequency (p &lt; 0.001), and caries status of deciduous teeth (p = 0.027). Maternal educational level (p = 0.026), paternal occupational status (p = 0.003), sweets and snacks taking frequency (p = 0.005), toothbrushing frequency (p &lt; 0.001), and fluoridate dentifrice usage (p = 0.027) were associated with moderate caries lesions. Maternal educational level (p &lt; 0.001), sweets and snacks taking frequency (p = 0.022) and toothbrushing frequen-cy (p &lt; 0.001) were associated with extensive caries lesions. Maternal educational level (p = 0.02) and brushing frequency (p &lt; 0.001) were statistically significantly associated with the highest prevalence of initial caries lesions. Maternal educational level (p = 0.025), toothbrushing frequency (p &lt; 0.001) and frequency of dental check-ups (p = 0.016) were statistically significantly associated with the highest prevalence of moderate caries lesions. Conclusion. Parental socioeconomic indicators and children's behavior related to oral health were involved in the changes from caries-free status to different caries stages.

Caries Risk Prediction Models in a Medical Health Care Setting

Despite development of new technologies for caries control, tooth decay in primary teeth remains a major global health problem. Caries risk assessment (CRA) models for toddlers and preschoolers are rare. Among them, almost all models use dental factors (e.g., past caries experience) to predict future caries risk, with limited clinical/community applicability owing to relatively uncommon dental visits compared to frequent medical visits during the first year of life. The objective of this study was to construct and evaluate risk prediction models using information easily accessible to medical practitioners to forecast caries at 2 and 3 y of age. Data were obtained from the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) mother-offspring cohort. Caries was diagnosed using modified International Caries Detection and Assessment System criteria. Risk prediction models were constructed using multivariable logistic regression coupled with receiver operating characteristic analyses. Imputation was performed using multiple imputation by chained equations to assess effect of missing data. Caries rates at ages 2 y (n = 535) and 3 y (n = 721) were 17.8% and 42.9%, respectively. Risk prediction models predicting overall caries risk at 2 and 3 y demonstrated area under the curve (AUC) (95% confidence interval) of 0.81 (0.75–0.87) and 0.79 (0.74–0.84), respectively, while those predicting moderate to extensive lesions showed 0.91 (0.85–0.97) and 0.79 (0.73–0.85), respectively. Postimputation results showed reduced AUC of 0.75 (0.74–0.81) and 0.71 (0.67–0.75) at years 2 and 3, respectively, for overall caries risk, while AUC was 0.84 (0.76–0.92) and 0.75 (0.70–0.80), respectively, for moderate to extensive caries. Addition of anterior caries significantly increased AUC in all year 3 models with or without imputation (all P < 0.05). Significant predictors/protectors were identified, including ethnicity, prenatal tobacco smoke exposure, history of allergies before 12 mo, history of chronic maternal illness, maternal brushing frequency, childbearing age, and so on. Integrating oral-general health care using medical CRA models may be promising in screening caries-susceptible infants/toddlers, especially when medical professionals are trained to “lift the lip” to identify anterior caries lesions.

Dental Caries Profile and Associated Risk Factors Among Adolescent School Children in an Urban South-Indian City.

To study the dental caries experience among adolescent school children in Chennai city using the ICDAS-II scoring system. The secondary objective was to identify associated risk factors to different thresholds of dental caries defined by ICDAS. Two hundred and thirty-seven children (13-17 years) from five schools across Chennai city were included using simple random sampling. After obtaining assent to participate in the study and satisfying the selection criteria, 200 children were screened for dental caries using ICDAS-II. The population was assessed for the following risk factors: sociodemographic status, habits, diet, plaque and salivary parameters. Prevalence of dental caries was estimated at the following thresholds: normal (ICDAS-0/1), mild caries (ICDAS-2), moderate caries (ICDAS-3/4) and extensive caries (ICDAS-5/6). Backward logistic regression analysis was performed to identify risk factors at different thresholds and crude odds ratio was calculated for statistically significant risk factors. The overall prevalence of dental caries (ICDAS 3-6) was 57.5% (95% CI 48-62%). The proportions of children at different caries thresholds were: ICDAS-2 - 55% (95% CI:48-62%), ICDAS-3/4 - 51% (95% CI:44-58%) and ICDAS-5/6 - 25% (95% CI:19-31%). Reduced pH was statistically significant for moderate and extensive caries (OR 6.24, 95% CI 1.18-32.78 and 1.73, 95% CI 1.18-1.92, respectively) and the quantity of saliva was statistically significant for mild and moderate caries (OR 4.48, 95% CI 2.94-8.23 and 3.97, 95% CI 2.65-7.03, respectively). Low buffering capacity was associated with mild caries OR 5.71, 95% CI 2.82-18.2). Interobserver correlation was 0.91. A non-statistically significant value using Hosmer-Lemeshow Goodness of Fit test indicated that all three models predict the true estimate of the population. The proportions of children with mild and moderate caries were high considering their age group. The risk factors associated with mild caries were different from those associated with moderate and extensive caries.

Recruitment of low-income pregnant women into a dietary and dental care intervention: lessons from a feasibility trial

BackgroundThere are difficulties in carrying out research in low-income urban communities, but the methodological challenges and suggestions on how to deal with them are often undocumented. The aims of this study are to describe the challenges of recruiting and enrolling low-income pregnant women with periodontitis to a clinical trial on vitamin D/calcium milk fortification and periodontal therapy and also to describe the patient-, study protocol- and setting-related factors related to women’s ineligibility and refusal to participate in the study.MethodsA mixed-method sequential exploratory design was applied. Qualitative and quantitative data on recruitment to a 2 × 2 factorial feasibility clinical trial were used. Eighteen women attending the health centre in a low-income area in Duque de Caxias (Rio de Janeiro, Brazil) took part in focus group discussions, and the data were thematically analysed. Quantitative data were analysed using appropriate descriptive statistics, including absolute and relative frequencies.ResultsOf all referrals (767), 548 (78.5%) did not meet the initial eligibility criteria. The main reason for exclusion (58%) was advanced gestational age (> 20 weeks) at first prenatal appointment. In the periodontal examination (dental screen), the main reason for exclusion was the presence of extensive caries (64 out of 127 exclusions). Non-participation of those eligible after the periodontal examination was approximately 24% (22 out 92 eligible women) and predominantly associated with patient-related barriers (e.g. transportation barriers, family obligations, patients being unresponsive to phone calls and disconnected telephones). The study recruited 70 women with periodontitis in 53 weeks and did not reach the benchmark of 120 women in 36 weeks (58.3% of the original target). Recruitment was severely hindered by health centre closures due to general strikes. The recruitment yields were 9.1% (70/767) of all women contacted at first prenatal visit and 76.1% (70/92) of those screened eligible and enrolled in the trial. Women did not report concerns regarding random allocation and considered fortified milk as a healthful and safe food for pregnant women. Some women reported that financial constraints (e.g. transportation costs) could hinder participation in the study.ConclusionEngagement between the research team and health centre staff (e.g. nurses) facilitated referral and recruitment, yet some pregnant women failed to participate in the study largely due to significant patient-related sociodemographic barriers and setting-related factors. Our data illustrate the complexity of overcoming recruitment and enrolment challenges for clinical trials in resource-limited settings.Trial registrationClinicalTrials.gov, NCT03148483. Registered on 11 May 2017.