Management of oblique root fracture in the middle third of two maxillary immature central incisors with severe caries in mixed dentitions: a case report.

Mid-root fractures are rare injuries in young permanent teeth and tend to have poor prognoses. This study presents a case of oblique root fracture of both maxillary immature central incisors in the middle third accompanied by delayed dental visit and severe caries of all primary teeth. After restoring all the primary and permanent teeth that needed stabilization, the coronal fragments were repositioned and stabilized with a flexible splint consisting of orthodontic wire and composite resin. A comprehensive and sequential dental treatment for other oral diseases and oral hygiene instructions were provided. A 16-month follow-up revealed that the two injured young permanent incisors were healed, surrounded by hard tissues and continued to grow both in length of the root and thickness of the root canal wall, with significant improvement in oral hygiene. Based on the outcome of this case, initial stabilization without endodontic therapy could be considered a successful treatment modality for young permanent teeth with oblique root fracture due to the growth of fractured teeth with vital pulp and the maintenance of natural dentition.

In Vitro Effect of Luting Cement on Fracture Resistance of Primary Maxillary Central Incisors with Fiber Posts.

Objectives: The use of fiber posts in endodontically treated primary maxillary central incisors improves the retention of composite resin restorations. The purpose of this study was to evaluate the effect of 4 different luting cements on fracture resistance of primary maxillary central incisors with fiber posts. Materials and Methods: In this in vitro study, 40 primary maxillary central incisors were endodontically treated and obturated with Metapex. They were then randomly divided into four groups (n=10) for cementation of fiber posts with GC Fuji I glass ionomer luting cement, Panavia F2.0 dual-cure luting cement, Panavia SA Luting Plus cement (self-adhesive), and TotalCem self-adhesive cement. After 1000 thermal cycles, the fracture resistance was measured. Data were statistically analyzed using ANOVA (alpha=0.05). Results: The mean fracture resistance was 267.07±130.01N in TotalCem, 257.27±102.56N in Panavia F2.0 dual-cure cement, 227.82±110.40N in Panavia SA Luting Plus self-adhesive cement, and 220.89±59.96N in GC Fuji I glass ionomer group. There was no statistically significant difference in fracture resistance among the four groups (P=0.714). Conclusion: Type of luting cement had no significant effect on fracture resistance of primary maxillary central incisors with fiber posts. Nonetheless, TotalCem yielded the highest fracture resistance. Considering its self-adhesive property and easy workability, it can be a good option for cementation of fiber posts in endodontically treated primary central incisors.

Six1 Regulates Mouse Incisor Development by Promoting Dlx1/2/5 Expression.

Tooth development is a complex process orchestrated by intricate gene regulatory networks, involving both odontogenic epithelium and ectomesenchyme. Six1, a pivotal transcription factor (TF), is involved in the development of the lower incisor. However, its precise role during incisor development and the molecular mechanisms underpinning its regulatory functions remain poorly understood. This study employs Six1 deletion mouse models to elucidate the critical regulatory role of Six1 in governing dental mesenchyme development. By performing single-cell RNA sequencing, we constructed a comprehensive transcriptome atlas of tooth germ development from the bud to bell stage. Our analyses suggest that the dental follicle and the dental papilla (DP) are differentiated from dental ectomesenchyme (DEM) and identify the key TFs underlying these distinct states. Notably, we show that Dlx1, Dlx2, and Dlx5 (Dlx1/2/5) may function as the key TFs that promote the formation of DP. We further show that the deletion of Six1 perturbs dental mesenchyme development by impeding the transitions from DEM to DP states. Importantly, SIX1 directly binds to the promoters of Dlx1/2/5 to promote their co-expression, which subsequently leads to widespread epigenetic and transcriptional remodeling. In summary, our findings unveil Six1's indispensable role in incisor development, offering key insights into TF-driven regulatory networks that govern dental mesenchyme cell fate transitions during tooth development.

Macrovibrissae and microvibrissae inversion and lateralization in elephants.

Elephants are known for strongly lateralized trunk behaviors, but the mechanisms driving elephant lateralization are poorly understood. Here, we investigate features of elephant mouth organization that presumably promote lateralization. We find the lower jaw of elephants is of narrow width, but is rostrally strongly elongated even beyond the jaw bone. Elephant lip vibrissae become progressively longer rostrally. Thus, elephants have two lateral dense, short microvibrissae arrays and central, less dense long macrovibrissae. This is an inversion of the ancestral mammalian facial vibrissae pattern, where central, dense short microvibrissae are flanked by two lateral macrovibrissae arrays. Elephant microvibrissae have smaller follicles than macrovibrissae. Similar to trunk-tip vibrissae, elephant lip microvibrissae show laterally asymmetric abrasion. Observations on Asian zoo elephants indicate lateralized abrasion results from lateralized feeding. It appears that the ancestral mammalian mouth (upper and lower lips, incisors, frontal microvibrissae) is shaped by oral food apprehension. The elephant mouth organization radically changed, however, because trunk-mediated feeding replaced oral apprehension. Such elephant mouth changes include the upper lip-nose fusion to the trunk, the super-flexible elongated lower jaw, the loss of incisors, and lateral rather than frontal microvibrissae. Elephants' specialization for lateral food insertion is reflected by the reduction in the centering effects of oral food apprehension and lip vibrissae patterns.

Anterior Maxillary Mesiodens Extraction in a Young Adult Male: A Case Report.

Mesiodens are classified as supernumerary teeth located in the maxilla, specifically in the palatal region between the central incisors. The prevalence of this condition varies between 0.15% and 1.9% among individuals. The presence of mesiodens can potentially affect the normal growth and development of teeth, leading to delayed eruption of permanent teeth, displacement or rotation of adjacent teeth, root resorption, and infectious pulpitis. This report discusses the case of a 14-year-old male patient who presented with a palatally placed mesiodens, which was completely erupted in the oral cavity. The patient underwent extraction for the removal of the mesiodens, and the procedure was successful with no complications reported during or after surgery. Early identification and surgical removal of mesiodens are crucial to preventing potential orthodontic and functional complications. This case highlights the importance of regular dental checkups for diagnosing supernumerary teeth. Timely intervention can lead to favorable outcomes, as demonstrated in this patient.

Incidence and treatment for hypomineralization of incisor and molar among school going Indian children.

The presence of molar incisor hypomineralization (MIH) raises the likelihood of enamel degradation, which in turn raises the risk of plaque buildup and dental caries. Individuals impacted by this illness frequently incur large long-term costs. Therefore, it is of interest to evaluate prevalence and treatment need of MIH in school going children. Hence, 3030 school going students were included in this study. Considering the WHO 1997 guidelines for caries severity and the requirement of therapy for the damaged teeth and criteria for MIH, a full mouth visual assessment of moist teeth was conducted for every student. The overall prevalence of MIH was 174 (7.9%). Preventive caries restricting therapy was needed in 42(6.2%) maxillary right first molar,30(4.5%) maxillary left first molar, 30 (4.5%) mandibular right first molar, 36 (5.4%) in mandibular left first molar. Data shows that an incidence rate of 7.4 percent was noted, with a larger propensity among male children and a predominant impact on mandibular molars.

Region-specific gene expression profiling of early mouse mandible uncovered SATB2 as a key molecule for teeth patterning.

Mammalian dentition exhibits distinct heterodonty, with more simple teeth located in the anterior area of the jaw and more complex teeth situated posteriorly. While some region-specific differences in signalling have been described previously, here we performed a comprehensive analysis of gene expression at the early stages of odontogenesis to obtain complete knowledge of the signalling pathways involved in early jaw patterning. Gene expression was analysed separately on anterior and posterior areas of the lower jaw at two early stages (E11.5 and E12.5) of odontogenesis. Gene expression profiling revealed distinct region-specific expression patterns in mouse mandibles, including several known BMP and FGF signalling members and we also identified several new molecules exhibiting significant differences in expression along the anterior-posterior axis, which potentially can play the role during incisor and molar specification. Next, we followed one of the anterior molecules, SATB2, which was expressed not only in the anterior mesenchyme where incisor germs are initiated, however, we uncovered a distinct SATB2-positive region in the mesenchyme closely surrounding molars. Satb2-deficient animals demonstrated defective incisor development confirming a crucial role of SATB2 in formation of anterior teeth. On the other hand, ectopic tooth germs were observed in the molar area indicating differential effect of Satb2-deficiency in individual jaw regions. In conclusion, our data provide a rich source of fundamental information, which can be used to determine molecular regulation driving early embryonic jaw patterning and serve for a deeper understanding of molecular signalling directed towards incisor and molar development.

Maxillary Central Incisor Eruption Failure Due to Supernumerary Teeth and Pericoronal Hamartoma: A Report of a Rare Case.

Impaction of permanent teeth during the replacement period is a relatively common occurrence in clinical practice. Tooth impaction occurs in the presence of factors that inhibit tooth eruption, such as supernumerary teeth or tumors. This is a report of permanent tooth impaction due to supernumerary teeth and pericoronal myxofibrous hyperplasia (PMH), a type of pericoronal hamartomatous lesion. An eight-year-old girl was diagnosed with an unerupted right maxillary central incisor. An inverted supernumerary tooth was present on the palatal side of the impacted central incisor, and PMH developed on the labial side of the central incisor. Interestingly, the alveolar bone on the labial side had completely disappeared. After the extraction of the supernumerary tooth and the removal of the PMH, the central incisors erupted, and the labial alveolar bone regenerated normally. Treatment for impacted teeth typically involves the removal of any existing lesions. This case is unique in that the alveolar bone of the impacted tooth regenerated following the extraction of the supernumerary tooth and removal of the PMH.

Diagnosis of Vertucci Type VII Anatomy in the Mandibular Left Lateral Incisor Using Digital Radiography: An Ex Vivo Case Study.

Mandibular lateral incisors sometimes feature an additional lingual canal, which, if not identified and missed during endodontic treatment, can lead to postoperative pain. Thus, a proper diagnosis of the internal anatomy of a tooth is necessary before treatment begins. Radiovisiography (RVG), a cost-effective and widely employed dental imaging technique, is used in clinics to visualize the internal root structure of teeth. The zoom function of RVG allows for a detailed examination of complex internal anatomical variations, facilitating a more accurate diagnosis and treatment planning process. This case study identified a rare Vertucci Type VII root canal system in a mandibular left lateral incisor using the zoom-in feature of radiovisiography (Vatech, EZ sensor). Additionally, horizontal sectioning was performed, and these sections were imaged to verify the accuracy of digital radiographs in diagnosing such cases as part of a preclinical demonstration for aspiring endodontists.

The Outcome of Decoronation in Severe Cases of External Cervical Root Resorption in Young Patients.

This study examines decoronation as a treatment option for teeth with progressive external cervical root resorption (ECR). Six young patients aged 9.5-13, with a total of nine incisor teeth affected by ECR due to previous dental trauma, were treated by decoronation. Six teeth were classified as class 4 and two as class 3, according to Heithersay's classification. Another tooth with class 2 resorption also had a perforation. After decoronation, all cases showed favorable outcomes during a follow-up period of 2.5-8 years. The procedure halted the progression of ECR and promoted vertical and horizontal ridge development above the submerged root. Decoronation can be considered for the successful treatment of advanced cases of ECR in young patients.

Effect of force direction and impaction angulation during dilaceration impacted central incisor traction: a finite element analysis.

BACKGROUND: The effects of traction forces at different angles on impacted central incisors(ICI)with varying inverted angles (IA) may be different. The objective of this study was to analyze the biomechanical effects of different force directions (FD) on developmentally inverted ICI with multi-angle variations and to offer insights and guidance for the treatment of inverted ICI. METHODS: Three-dimensional finite element method was employed to simulate clinical scenarios of inverted ICI traction. As such, 0.2 N of force (direction: antero-superior angles of 90°, 100°, 110°, 120°, and 130° relative to the long axis of the inverted ICI crown) was applied to the inverted ICI with inverse angles (IA) of 40°, 30°, 20°, 10° and 0°. Inverted ICI apical displacement and Von Mises stress on periodontal ligament (PDL) and alveolar bone were compared. RESULTS: IA and FD showed minimal influence on the stress distribution in the PDL, as higher stresses were concentrated in the apical region. The higher stresses in the alveolar bone are focused on the cervical and apical regions of the tooth. In particular, IA exerts a more significant impact on stress distribution in the alveolar bone than FD. The influence of IA on the apical displacement of inverted ICI is larger than that of FD. CONCLUSIONS: To promote the health of the root and periodontal tissues, it is recommended to use an angle of 100°-110° relative to the long axis of the ICI crown when dealing with a large IA (> 20°) developmentally inverted ICI. Conversely, an angle of 110°-120° can be used.

A Synthetic Small Molecule, LGM2605: A Promising Modulator of Increased Pro-Inflammatory Cytokine and Osteoclast Differentiation by Aggregatibacter actinomycetemcomitans Cytolethal Distending Toxin.

Our research explores the interplay between Aggregatibacter actinomycetemcomitans (Aa) cytolethal distending toxin (Cdt) and the host's inflammatory response in molar/incisor pattern periodontitis (MIPP). Cdt disrupts phosphatidylinositol-3,4,5-triphosphate (PIP3) signaling, influencing cytokine expression through canonical and non-canonical inflammasome activation as well as nuclear factor-κB (NF-κB) activation, leading to inflammation in MIPP. THP-1 differentiated macrophages (TDMs) exposed to Cdt exhibited an upregulation of pro-inflammatory genes and subsequent cytokine release. We analyzed the ability of a small molecule therapeutic, LGM2605, known for its anti-inflammatory properties, to reduce pro-inflammatory gene expression and cytokine release in Cdt-exposed and Aa-inoculated TDMs. LGM2605's mechanism of action involves inhibiting NF-κB while activating the Nrf2-transcription factor and antioxidants. Herein, we show that this small molecule therapeutic mitigates Cdt-induced pro-inflammatory cytokine expression and secretion. Our study also further defines Cdt's impact on osteoclast differentiation and maturation in MIPP. Cdt promotes increased TRAP+ cells, indicating heightened osteoclast differentiation, specific to Cdt's phosphatase activity. Cathepsin K levels rise during this process, reflecting changes in TRAP distribution between control and Cdt-treated cells. Exploring LGM2605's effect on Cdt-induced osteoclast differentiation and maturation, we found TRAP+ cells significantly reduced with LGM2605 treatment compared to Cdt alone. Upon LGM2605 treatment, immunocytochemistry revealed a decreased TRAP intensity and number of multinucleated cells. Moreover, immunoblotting showed reduced TRAP and cathepsin K levels, suggesting LGM2605's potential to curb osteoclast differentiation and maturation by modulating inflammatory cytokines, possibly involving Nrf2 activation. In summary, our research reveals the intricate connections between Cdt, pro-inflammatory cytokines, and osteoclast differentiation, offering novel therapeutic possibilities for managing these conditions.

Association between molar-incisor hypomineralisation and dental anomalies.

BACKGROUND: Common etiological factors have been reported in the development of molar-incisor hypomineralisation (MIH) and dental anomalies (DA). AIM: To assess the association between MIH and DAs. DESIGN: A cross-sectional study was performed to evaluate the presence of MIH and other six DAs in a sample of 415 pretreatment records from patients aged 9-18 years. Statistical analyses were performed using the chi-squared and Fisher's exact tests, and logistic regressions. RESULTS: There was statistically significant association between the prevalence of DAs and MIH (CI: 1.43-2.43, φ-coefficient: 0.204, PR: 1.87). Higher percentage of tooth agenesis (CI: 1.37-1.68, φ-coefficient: 0.271, PR: 1.50), maxillary premolar agenesis (CI: 1.70-3.65, φ-coefficient: 0.125, PR: 2.49), mandibular second premolar agenesis (CI: 1.68-3.16, φ-coefficient: 0.172, PR: 2.30) and distoangulation of the mandibular second premolars (CI: 1.31-3.47, φ-coefficient: 0.103, PR: 2.13) was observed among children who had MIH-affected teeth. Individuals with MIH had a 2.95 times greater chance of having DAs (R2 = .153). The number of patients with DAs was higher when the first molar showed severe defects (OR = 4.47; R2 = .149). CONCLUSION: There is a weak association between MIH and DAs. Patients with severe MIH lesions have a slightly higher risk of presenting DAs.

Effect of the filling technique on the filling removal from oval-shaped canals.

OBJECTIVES: This ex vivo study aimed to evaluate the influence of different filling techniques on the filling removal from oval root canals filled with bioceramic sealer. METHODS: Thirty-six mandibular incisors with single oval canals were filled with bioceramic sealer following the techniques (n = 12): single-cone, modified McSpadden, or continuous wave of condensation, and scanned by micro-computed tomography (micro-CT). The filling was removed using the Clearsonic ultrasound tip and Reciproc system up to the R40 instrument, and the working time was recorded. The teeth were scanned again by micro-CT. Percentage of remnant volume (mm³) of the filling material, dentin thickness, and root canal transportation were measured. The data was analyzed using parametric and non-parametric tests with a significance level of 5%. RESULTS: It took more time to remove the filling material using the continuous wave of condensation technique (p < 0.05), followed by the modified McSpadden and single-cone techniques. There was no difference (p > 0.05) when comparing the percentage of remaining filling material among the three groups, nor did it among the segments of each tooth. There was also no difference in the analysis of dentin thickness and transportation when comparing the groups (p > 0.05). CONCLUSIONS: The filling technique did not influence the amount of remaining filling material, dentin thickness, and transportation. The working time was longer with thermoplastic filling techniques. CLINICAL RELEVANCE: Endodontic retreatment in teeth filled with bioceramic sealers increases with their use. Several techniques are used to fill the root canals, thus, it is important to know whether the filling technique influences the non-surgical endodontic retreatment.

Genetic polymorphisms associated with developmental defects of enamel: A systematic review.

BACKGROUND: Polymorphisms in genes related to enamel formation and mineralization may increase the risk of developmental defects of enamel (DDE). AIM: To evaluate the existing literature on genetic polymorphisms associated with DDE. DESIGN: This systematic review was registered in the PROSPERO (CRD42018115270). The literature search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library, and in the gray literature. Observational studies assessing the association between DDE and genetic polymorphism were included. The Newcastle-Ottawa Scale was used to assess the risk of bias. RESULTS: One thousand one hundred and forty-six articles were identified, and 28 met the inclusion criteria. Five studies presented a low risk of bias. Ninety-two genes related to enamel development, craniofacial patterning morphogenesis, immune response, and hormone transcription/reception were included. Molar-incisor hypomineralization (MIH) and/or hypomineralization of primary second molars (HPSM) were associated with 80 polymorphisms of genes responsible for enamel development, immune response, morphogenesis, and xenobiotic detoxication. A significant association was found between the different clinical manifestations of dental fluorosis (DF) with nine polymorphisms of genes responsible for enamel development, craniofacial development, hormonal transcription/reception, and oxidative stress. Hypoplasia was associated with polymorphisms located in intronic regions. CONCLUSION: MIH, HPSM, DF, and hypoplasia reported as having a complex etiology are significantly associated with genetic polymorphisms of several genes.

What can impact on the presence of carious lesions in first permanent molars? Revisiting the association between MIH and caries.

OBJECTIVE: Assess whether the independent variables (IV) such as number of MIH-affected molars, MIH severity, past caries experience, visible plaque index (VPI), gingival bleeding index (GBI), age, and gender affect the presence of caries lesion (DMF_s) in first permanent molars, considering or not atypical restoration in MIH-affected molars as a previous caries lesion. METHODS: A sample of 476 schoolchildren, aged 6-10 years, were evaluated for MIH and caries diagnosis, using the Severity Scoring System (MIH-SSS) and the International Caries Detection and Assessment System (ICDAS), respectively. From the ICDAS, the DF-s/ D-s and df-s were calculated. The Zero-inflated Negative Binomial Regression was used to evaluate the impact of the IV on the dependent variable, considering or not the restorative component in MIH-affected molars. RESULTS: When the presence of caries was evaluated with the restorative component, age, MIH severity and past caries experience had a significant impact on the dependent variable (R2 = 0.176). Without the restorative component in MIH-affected molars, only age and past caries experience were statistically significant (R2 = 0.167). CONCLUSION: Since in the case of MIH teeth restoration may be attributed to post-eruptive breakdown rather than previous caries lesions, in the present study MIH did not influence the presence of caries lesions in the MIH-affected molars showing that restoration is not an adequate parameter for measuring the historical occurrence of caries. CLINICAL RELEVANCE: The first permanent molars may not necessarily be at an increased risk of caries due to MIH if the etiological factors for caries development are effectively managed.

Analysis of the stomatognathic system functions and mastication muscles in children affected by molar hypomineralization (MH): a cross-sectional study.

PURPOSE: To analyze the functions of the stomatognathic system in children with or without molar-incisor hypomineralization (MIH). METHODS: For this cross-sectional study, 72 children aged 6-12 years were recruited and divided in two groups: with MIH (G1) and without MIH (G2). T-SCAN was used to verify the distribution of occlusal contacts, gnathodynamometer to measure maximum molar bite force, and Iowa Oral Pressure Instrument (IOPI) to assess the strength of facial expression muscles. The t test and paired t test (p ≤ 0.05) were used for statistical comparisons. RESULTS: The molars affected by MIH exhibited lower distribution of occlusal forces (p < 0.001) and lower maximum molar bite force (p < 0.05) compared to the molars in the control group. However, there was no difference between the MIH-affected sides compared to the unaffected side, nor between the molars affected by MIH and their antagonists (p > 0.05). There were no differences in the forces of the facial expression muscles between the groups. CONCLUSIONS: These findings suggest that MIH significantly impacts occlusal force distribution and bite force, but not facial expression musculature.

Unlocking Hidden Teeth: A Pediatric Case of Surgical Exposure of Maxillary Central Incisors.

Failure in the eruption of the maxillary incisor necessitates a precise diagnosis and treatment regimen. Impaction can have a number of causes such as physical obstacles in the eruption path, discrepancy in the length of the dental arch, and tooth anomaly. Delayed eruption of anterior teeth can result in a number of issues such as malocclusion and psychological discomfort. In many cases, if the intervention is not done at an early stage, complex orthodontic intervention is required after surgical exposure to enable appropriate eruption. This case report is of a nine-year-old child with unerupted maxillary central incisors. The child was treated surgically for incisor exposure under general anesthesia (GA). Both functional and aesthetic considerations made this surgical procedure necessary. GA was administered due to the negative behavior of the child in a dental setting. Hence, it ensured patient comfort and cooperation. Follow-up examinations showed satisfactory progress in the eruption of the teeth with no complications.

Effectiveness of resin infiltration in the management of anterior teeth affected by molar incisor hypomineralisation (MIH): A systematic review and meta-analysis.

OBJECTIVES: To evaluate the effectiveness of resin infiltration in improving the aesthetic appearance of anterior teeth affected by molar-incisor hypomineralisation (MIH). DATA SOURCES: PubMed, Scopus, EMBASE, Web of Science, ScienceDirect, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched from 2009 to 2024. The protocol was registered in the International Prospective Database of Systematic Reviews (PROSPERO CRD42023461909). STUDY SELECTION: Interventional or comparative studies comparing resin infiltration and other treatments in MIH-affected anterior teeth were included. The risk of bias was evaluated using the Risk Of Bias In Non-randomised Studies of Interventions (ROBINS-I tool) and the Risk of Bias 2 (RoB 2.0) tool. Meta-analysis utilized a random-effects model. DATA: Eighteen studies met the inclusion criteria, and twelve were included in the meta-analysis. Resin infiltration showed a higher color difference (ΔE) before and after treatment (mean difference 2.21, 95 % confidence interval [CI] 0.04-4.38, p < 0.001, I2 = 98.61 %, p < 0.001) and better optical improvement (standardised mean difference [SMD] 2.68; 95 %CI 0.30-5.06; p = 0.027, I2 = 97.8 %, p < 0.001) compared to controls. The estimated success rate based on dentist assessment was 92 % (95 %CI 88-95 %, I2 = 17.92 %, p = 0.06). Non-randomised trials showed high (8/14) or moderate (6/14) risk of bias, mainly from confounding and selection issues. Randomised trials had high risk (1/3) or some concerns (2/3) due to missing data. CONCLUSIONS: The findings suggest that resin infiltration significantly improves aesthetic outcomes in MIH-affected anterior teeth, as evidenced by higher colour difference and optical improvement compared to controls. CLINICAL SIGNIFICANCE: While our study shows promising results for resin infiltration, including high success rates and aesthetic improvements, larger-scale studies with longer follow-up periods are necessary to confirm these findings and assess its long-term efficacy.

Which are the clinical consequences of Molar Incisor hypomineralization (MIH) in children and adolescents? Systematic review and meta-analysis.

OBJECTIVE: This systematic review was conducted to address the following research question: "What are the clinical consequences (outcome) of Molar Incisor Hypomineralization (MIH) (exposure) in children and adolescents (population/patient)?". MATERIAL AND METHODS: After defining the strategy, a search was performed in different databases (MEDLINE via Pubmed, Cochrane Library, BBO, LILACS, Scopus, Web of Science, Embase) and Grey literature in August 2023. Cross-sectional observational studies that identified clinical consequences of MIH (dental caries, post-eruptive structural loss, atypical restorations, hypersensitivity and tooth extraction) were included. The risk of bias was assessed following the Joanna Briggs Institute protocol for cross-sectional studies. Meta-analyses were conducted for each outcome, taking into account the number of patients and teeth. The effect measure considered was the prevalence; random-effects model was adopted. Heterogeneity was assessed using I2 statistics and prediction intervals (PI). RESULTS: A total of 903 studies were identified; 41 were selected for qualitative analysis and 38 for quantitative analysis. Twenty eight studies were classified as presenting uncertain risk of bias, 11 as low risk and 3 as high risk of bias. The prevalence levels, ranked from highest to lowest and considering the tooth and patient units, respectively, were: caries lesions (0.252 - 95% CI 0.158-0.375; 0.512 - 95% CI 0.385-0.639); hypersensitivity (0.286 - 95% CI 0.190-0.407; 0.417 - 95% CI 0.197-0.674), post-eruptive fracture (0.125 - 95% CI 0.099-0.158; 0.257 - 95% CI 0.145-0.412); atypical restorations (0.048 - 95% CI 0.030-0.077; 0.167 - 95% CI 0.096 - 0.274); tooth extraction (0.012 - 95% CI 0.007-0.019; 0.090 - 95% CI 0.019 - 0.331). All meta-analyses resulted in heterogeneity greater than 85%, with the exception of the outcome "tooth extraction" according to the tooth unit (I2 = 57.83). This heterogeneity may be attributed to factors such as differences in the location where the study was realized, the socioeconomic conditions of the studied population, the asymmetric nature of MIH, and patient age. CONCLUSION: The most common consequences of MIH are caries lesions, hypersensitivity, and post-eruptive breakdown. (PROSPERO:CRD42020201410).