Approximal morphology as predictor of approximal caries in primary molar teeth

3D intraoral scanning techniques support the effects of crown morphology on dental caries

BACKGROUND

With the development and utilization of three-dimensional (3D) intraoral scanning (IOS) technology, the morphological characteristics of teeth were quantitatively assessed. In this research, we aimed to explore the prevalence of dental caries in relation to each measurable morphological indicator of the tooth body via 3D intraoral scanning techniques.

METHODS

A hospital-based single-centre study was conducted at our hospital from Dec. 2021 to Apr. 2023. A total of 53 patients were involved in the study, providing complete morphological data for 79 teeth. Each patient completed an oral hygiene routine questionnaire and underwent examination by an experienced dentist to evaluate caries conditions before undergoing 3D intraoral scanning to obtain a digital dental model. Geomagic Studio 2014 was used to extract oral morphological data from the models. The acquired data were entered, cleaned and edited using Excel 2016 and subsequently exported to SPSS version 25.0 for analysis. Chi-square analysis and logistic regression analyses were employed to test the associations.

RESULTS

Among the participants, 33 (61.1%) were female, with a mean age of 26.52 ± 10.83 years. Significant associations were found between dental caries and the vertical distance between the distal tip and the gum (OR 14.02; 95% CI 1.80-109.07; P = 0.012), the distal lateral horizontal distance of occlusion (OR 0.40; 95% CI 0.18-0.90; P = 0.026), and the mesial horizontal distance of occlusion (OR 2.20; 95% CI 1.12-4.31; P = 0.021). The Hosmer-Lemeshow test indicated a P value of 0.33.

CONCLUSIONS

The vertical distance between the distal tip and the gum, the distal lateral horizontal distance of the occlusion and the mesial horizontal distance of the occlusion were the influencing factors for dental caries (identified as independent risk factors). We hypothesize that these factors may be associated with the physiological curvature of teeth and the role of chewing grooves in plaque formation over time. However, further studies involving larger population samples and more detailed age stratification are still needed.

Variation of OXIS contact areas in primary molars among 3-6-year-old children with intraoral digital scanning

PURPOSE

To determine the variation of OXIS contact areas in primary molars using digital impressions generated from an intraoral scanner (IOS).

METHODS

A cross-sectional study was carried out on 214 caries-free posterior quadrants of 80 children (38 males and 42 females) aged 3-6 years. Calibration of taking digital impressions with the IOS procedure was performed initially through scanning of ten quadrants of children to provide a learning environment to the examiner. The digital impressions were then exported, and the type of interproximal contact areas present between the distal surface of the primary first molar and the mesial surface of the primary second molar were identified according to the OXIS classification. The prevalence of the types of OXIS contact areas was expressed in the form of numbers and percentages. The chi-square test was applied to investigate the variability among the arches and to understand the association of OXIS contact areas across age, gender, and arches.

RESULTS

The most common contact area type observed was I-type (59.8%), followed by S-type (15.4%), X-type (12.6%), and O-type (12.2%). The I-type contact area was most frequently seen in both males (51.6%) and females (65.5%), while the S-type contact area in males (14.7%) and X-type contact area in females (8.4% each) were the least frequent with no statistical significance between genders (p > 0.05). All three age groups studied showed the highest prevalence of the I-type contact area, which increased with an increase in age (p < 0.05). The inter-arch comparison showed a significant result in terms of the X-type contact area on the right side, and O-type, X-type, and I-type contact areas on the left side, while no statistical difference was seen in the intra-arch comparison for all contact types.

CONCLUSION

I-type contact areas were the most prevalent across the arches, age groups and genders.

Clinical validation of near-infrared imaging for early detection of proximal caries in primary molars

OBJECTIVES

The aim of this study was to validate the near-infrared imaging (NIRI) in comparison with visual inspection (VI) for early detection of proximal caries in primary molars.

METHODS

VI and intraoral scans were performed on 126 patients aged 3-12 years with at least one non-cavitied and non-restored proximal tooth surface, who were scheduled for bite wing radiography (BWR) as part of their standard care. Teeth with signs of proximal cavities, restorations or residual caries were excluded in this study. BWR, a gold standard to diagnose proximal caries in primary molars, was used to validate the findings of NIRI and VI. The accuracy, sensitivity, specificity and the area under the curve (AUC) of NIRI and VI were calculated.

RESULTS

The accuracy, sensitivity and specificity of NIRI were 82.89%, 74.10% and 90.97%, while those of VI were 71.64%, 43.88% and 97.14%, respectively. NIRI showed higher accuracy and sensitivity, and lower specificity (P < 0.001). The AUC of NIRI was higher than that of VI (0.826 vs 0.706; P < 0.05).

CONCLUSIONS

NIRI showed higher sensitivity and lower specificity compared with VI when detecting proximal caries in primary molars. Therefore, it is recommended to use NIRI in combination with BWR to improve the detection rate of proximal caries in primary molars.

CLINICAL SIGNIFICANCE

In children, there is a high incidence of proximal caries in primary molars, which require high technical sensitivity for detection. NIRI shows high sensitivity in detecting proximal caries, which may improve their detection rate in primary molars.

THE CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2300070916.

Dental caries in Rwanda: A scoping review

Background and Aims

Dental caries is an infectious disease affecting virtually all nations, including Rwanda. In Rwanda, the burden of dental caries is an issue of public health concern. To ensure the progressive eradication of the current dental caries burden in Rwanda through an evidence-based approach, it is imperative to have an overview of the scientific research landscape of dental caries in the country. This study-a scoping review-aims to review the available evidence and gaps on dental caries in Rwanda.

Methods

This scoping review was reported based on the Preferred Reporting Items for systematic reviews and meta-analyses extension for Scoping Reviews checklist. A systematic search of 11 databases was done to scoop out all literature relevant to the topic. Based on the review's selection criteria, a total of eight peer-reviewed journal articles were included in the review. The extracted data were collated, summarized, and presented as results.

Results

The analysis of the data extracted from the included articles revealed a high prevalence of dental caries (ranging from 42.42% to 71.5%) in Rwanda. Also, the major pathogens causing dental caries in Rwanda as well as the impact of dental caries on the physical health and quality of life of Rwandans were identified in this review. Furthermore, the reported operative treatment options for dental caries in Rwanda were predominantly nonconservative. Also, no intervention study has been conducted on dental caries in Rwanda.

Conclusion

The findings in this review identify the need for massive public health interventions on dental caries in Rwanda.

Morphological analysis of anterior permanent dentition in a Chinese population using cone-beam computed tomography

PURPOSE

Morphological analysis of permanent anterior dentition is essential for achieving an ideal treatment outcome and avoiding unnecessary failure. This study aimed to analyze the morphologies of anterior teeth in the Chinese population in depth.

METHODS

In this retrospective study, 4309 anterior teeth from 401 Chinese patients were investigated using cone-beam computed tomography (CBCT) from 2019-2021. We summarized the morphological characteristics of the anterior teeth in terms of the root length, cementoenamel junction curvature (CEJ-C), root furcation and canal variations.

RESULTS

We found that the root lengths of the maxillary anterior incisors were similar (13.3 mm), while the root lengths of the mandibular central (12.2 mm) and lateral incisors (13.4 mm) varied significantly (p < .0001). Both the maxillary (16.6 mm) and mandibular canines (15.5 mm) were found to have greater root lengths than the corresponding incisors (p < .0001). The CEJ-C was significantly greater around incisors (2.5 mm) than around the canines (2.0 mm) in the maxilla (p < .0001), while the curvature remained similar in mandibular anterior teeth (1.8 mm). Root furcation was observed in mandibular canines and lateral incisors. Moreover, all types of Vertucci's classification in anterior dentitions were observed, while two other new types were found. Among them, the maxilla was only observed to exhibit types I, II, III, and ST II, while the mandible was found to exhibit almost all types. However, Type I still accounts for the majority of dentitions.

CONCLUSIONS

Morphological analysis of permanent anterior dentition revealed diversity in the tooth length, CEJ-C, furcation proportion, and canal variations. In general, mandibular anterior teeth showed a more complex structure than maxillary teeth.

Modified OXIS classification for primary canines

Background: A new classification called OXIS was proposed for categorising the interproximal contacts of primary molars, and its prevalence was established. The aim of this study was to establish the variations in interproximal contacts of primary canines and thereby modify the OXIS classification of primary molars to primary canines. Additionally, we aimed to estimate the applicability of modifications to primary anterior teeth.

Methods: A retrospective study was conducted with sectional die models obtained from a previous study of 1,090 caries-free children. Two calibrated examiners evaluated a total of 4,674 contacts from the occlusal aspect. The contacts were scored according to the former OXIS classification, with two modifications incorporated to encompass the morphological differences and rotations of primary canines and other primary anterior teeth.

Results: The most prevalent contact was O (62.1%), followed by X (19.6%), I (12.6%), S type I (4.1%), and S type II (1.6%). Inter-arch comparison by means of the Chi-square test revealed significant differences for all types of contacts ( P < .001).

Conclusions: The interproximal contacts of canines were categorised as O, X, I, S I, and S II. The OXIS classification of primary molars was modified to befit the variations in primary canines. This study showed the presence of different types of contacts in primary canines. Identification of these contacts and their complexity has warranted a need for this to be studied as an inherent risk factor for caries risk assessment.

Modified OXIS classification for primary canines

Background: A new classification called OXIS was proposed for categorising the interproximal contacts of primary molars, and its prevalence was established. The aim of this study was to establish the variations in interproximal contacts of primary canines and thereby modify the OXIS classification of primary molars to primary canines. Additionally, we aimed to estimate the applicability of modifications to primary anterior teeth. Methods: A retrospective study was conducted with sectional die models obtained from a previous study of 1,090 caries-free children. Two calibrated examiners evaluated a total of 4,674 contacts from the occlusal aspect. The contacts were scored according to the former OXIS classification, with two modifications incorporated to encompass the morphological differences and rotations of primary canines and other primary anterior teeth. Results: The most prevalent contact was O (62.1%), followed by X (19.6%), I (12.6%), S type I (4.1%), and S type II (1.6%). Inter-arch comparison by means of the Chi-square test revealed significant differences for all types of contacts (P < .001). Conclusions: The interproximal contacts of canines were categorised as O, X, I, S I, and S II. The OXIS classification of primary molars was modified to befit the variations in primary canines. This study showed the presence of different types of contacts in primary canines. Identification of these contacts and their complexity has warranted a need for this to be studied as an inherent risk factor for caries risk assessment.

Quality of approximal surfaces of posterior restorations in primary molars

PURPOSE

To evaluate the influence of the restorative material and matrix system on proximal contact tightness and morphological characteristics of class II restorations in primary molars.

METHODS

Occluso-mesial cavities in second primary artificial molars were randomly restored using different materials (Filtek Z500 or Filtek Bulk Fill composites or high-viscosity glass ionomer cement Ketac Universal) and different matrix system (Tofflemire, AutoMatrix, matrix band with ring, contoured sectional matrix) (n = 12). Proximal contact tightness was measured using a custom-made device in an Instron 3345, and proximal surface morphology and marginal adaptation were scored after digital scanning. Two-way ANOVA, Tukey and Fischer's exact tests were performed (P < 0.05).

RESULTS

Proximal contact tightness values were significantly influenced by the restorative material (P < 0.05), the matrix system (P < 0.001), and their interaction (P < 0.01). Both resin composites showed statistically differences in proximal shape according to the matrix used to restore and exhibited overhanging margins. Ketac Universal restorations showed similar morphology and gaps on the margins regardless of the matrix system.

CONCLUSIONS

Overall, both composite restorations achieved tighter proximal contact than those restored with the high-viscosity glass ionomer cement. None of the matrix systems tested provided a convex seamless proximal morphology.

Risk factors for dental caries in Latin American and Caribbean countries

Identifying the risk factors for dental caries is vital in epidemiology and clinical practices for developing effective preventive strategies, both, at the individual and collective levels. Different causality/determination models have been proposed to understand the development process of dental caries. In the present review, we designed a model inspired by the world-known social determinants models proposed in the 90s and more recently in the 10s, wherein the contextual factors are placed more externally and encompass the individual factors. The contextual factors included those related to the cultural and societal values, as well as the social and health government policies. The individual factors were classified into the following categories: socioeconomic (social class, occupation, income, and education level), demographic characteristics (age, sex, and ethnicity), behavioral factors (non-use of fluoride dentifrice, sugar consumption, poor oral hygiene, and lack of preventive dental care), and biological factors (recent caries experience/active caries lesions, biofilm retentive factors, developmental defects of the enamel, disabilities, saliva amount and quality, cariogenic biofilm). Each of these variables was addressed, while focusing on the current evidence from studies conducted in Latin American and Caribbean countries (LACC). Based on the proposed model, educational aspects were addressed, and individual caries risk assessment and management decisions were proposed; further, implications for public health policies and clinical practice were described. The identification of modifiable risk factors for dental caries should be the basis for multi-strategy actions that consider the diversity of Latin American communities.

Interproximal contact areas of primary molars based on OXIS classification - a two centre cross sectional study

Background: Contact areas in primary teeth are known to be broader, flatter and situated farther gingivally than permanent teeth. The purpose of this study was to assess the prevalence of OXIS contact areas between primary molars using die models of children from two different ethnic populations. The research question of the present study is "What is the prevalence OXIS contact areas of primary molars in the populations studied?". Methods: A cross-sectional study was planned in a representative sample of 200 caries-free contact areas among children aged 3-6 years in two centers, Ajman and Puducherry. Data collection was performed from sectional or full-arch die stone models. The contacts were assessed according to OXIS classification by a single calibrated examiner at Center 2. Prevalence was expressed as numbers and percentages. The Chi-square test was applied to determine the association of OXIS contacts across genders and arches. Results: The prevalence of O, X, I, and S contacts were 19%, 22.5%, 53%, and 5.5% in Center 1 and 6%, 1.5%, 75.5%, and 17% in Center 2, respectively. Significant results (p=0.005) were obtained in Center 1 when inter-arch comparison was performed and between the centers with respect to type of contact. No significant difference was obtained with respect to gender and OXIS contact areas. Conclusions: The present study confirmed OXIS contacts in both the centers. The 'O' and 'X' types of contacts were observed more in Center 1, whereas 'I' and 'S' contacts were observed more in Center 2.

OXIS contact areas of primary molars - a two center cross-sectional study

Background: Contact areas in primary teeth are known to be broader, flatter and situated farther gingivally than permanent teeth. The purpose of this study was to assess the prevalence of OXIS contact areas between primary molars using die models of children from two different ethnic populations. The research question of the present study is "What is the prevalence OXIS contact areas of primary molars in the populations studied?". Methods: A cross-sectional study was planned in a representative sample of 200 caries-free contact areas among children aged 3-6 years in two centers, Ajman and Puducherry. Data collection was performed from sectional or full-arch die stone models. The contacts were assessed according to OXIS classification by a single calibrated examiner at Center 2. Prevalence was expressed as numbers and percentages. The Chi-square test was applied to determine the association of OXIS contacts across genders and arches. Results: The prevalence of O, X, I, and S contacts were 19%, 22.5%, 53%, and 5.5% in Center 1 and 6%, 1.5%, 75.5%, and 17% in Center 2, respectively. Significant results (p=0.005) were obtained in Center 1 when inter-arch comparison was performed and between the centers with respect to type of contact. No significant difference was obtained with respect to gender and OXIS contact areas. Conclusions: The present study confirmed OXIS contacts in both the centers. The 'O' and 'X' types of contacts were observed more in Center 1, whereas 'I' and 'S' contacts were observed more in Center 2.

Longitudinal assessment on the impact of caries status of nearby surfaces on caries progression on the mesial surface of first molars

BACKGROUND

The mesial surface of the first permanent molar is the most caries-susceptible proximal surface of the permanent dentition in children under the age of 12.

AIM

The aim of this study was to determine the association between caries progression on the mesial surface of the first permanent molar (T6M) and caries on the distal surface of the primary second molar (t5D) and the occlusal surface of the first permanent molar (T6O).

DESIGN

Children (between 5 and 13 years old; N = 565) that had participated in a 4-year longitudinal caries study that at baseline had at least one T6 fully erupted with a t5 in proximal contact, with no restoration or sealant on T6O and t5D, and adequate bitewing radiographs were included. Clinical data using the International Caries Detection and Assessment System (ICDAS) and radiographs were used to determine the caries status of T6M, T6O, and t5D.

RESULTS

Baseline caries presence on t5D and T6O were highly significantly associated with follow-up caries presence on T6M (P < .001). The adjusted odds ratios corresponding to t5D and T6O were 3.94 (95% CI: [1.78, 8.71]) and 3.26 (95% CI: [1.46, 7.31]), respectively.

CONCLUSION

These findings highlight the need for prevention and management of caries on T6O and t5D.

Microbial biogeography and ecology of the mouth and implications for periodontal diseases

In humans, the composition of microbial communities differs among body sites and between habitats within a single site. Patterns of variation in the distribution of organisms across time and space are referred to as "biogeography." The human oral cavity is a critical observatory for exploring microbial biogeography because it is spatially structured, easily accessible, and its microbiota has been linked to the promotion of both health and disease. The biogeographic features of microbial communities residing in spatially distinct, but ecologically similar, environments on the human body, including the subgingival crevice, have not yet been adequately explored. The purpose of this paper is twofold. First, we seek to provide the dental community with a primer on biogeographic theory, highlighting its relevance to the study of the human oral cavity. We summarize what is known about the biogeographic variation of dental caries and periodontitis and postulate that disease occurrence reflects spatial patterning in the composition and structure of oral microbial communities. Second, we present a number of methods that investigators can use to test specific hypotheses using biogeographic theory. To anchor our discussion, we apply each method to a case study and examine the spatial variation of the human subgingival microbiota in 2 individuals. Our case study suggests that the composition of subgingival communities may conform to an anterior-to-posterior gradient within the oral cavity. The gradient appears to be structured by both deterministic and nondeterministic processes, although additional work is needed to confirm these findings. A better understanding of biogeographic patterns and processes will lead to improved efficacy of dental interventions targeting the oral microbiota.

Sialometry and concentration of phosphate and calcium in stimulated whole saliva and gingival crevicular fluid and its association with dental caries in schoolchildren

Introduction: The remineralizing properties of saliva contribute to maintain the physical and chemical integrity of the mineral structure of teeth, which protects it from the installation and evolution of dental caries. Objective: To relate sialometry, buffering capacity, calcium and phosphate concentration in whole stimulated saliva, and in gingival crevicular fluid with school children caries severity and activity. Materials and methods: We selected 36 schoolchildren aged 6 years: 18 with caries (International Caries Detection and Assessment System, ICDAS>1 group) and 18 without caries (ICDAS=0 group). The severity and activity of dental caries were diagnosed in the primary dentition: in the occlusal surface of molars and in the vestibular of the anterior teeth by ICDAS-II. Results: Caries in occlusal surface were more severe than in vestibular surface. The concentration of calcium in saliva and phosphate in healthy teeth gingival crevicular fluid were higher in the ICDAS>1 group. The concentration of calcium in gingival crevicular fluid was higher in the ICDAS=0 group than in the decayed teeth of the ICDAS>1 group. We found a statistically significant association between the frequency of active caries andthe concentration of phosphate in gingival crevicular fluid of teeth with caries, as well as between the severity of caries with buffering capacity and the concentration of phosphate in the gingival crevicular fluid of teeth with caries. Conclusion: We found an association between dental caries with buffering capacity and buccal calcium and phosphate.