Fluorescence-Aided Identification Technique (FIT) Improves Tooth Surface Clean-Up after Debonding of Buccal and Lingual Orthodontic Appliances

The aim of this study was to evaluate the use of fluorescence inducing light to aid the clean-up of tooth surfaces after bracket removal when using buccal or lingual orthodontic appliances. Two full sets of dental arches using extracted human teeth were assembled, with 14 teeth per arch. All teeth were bonded on their buccal and lingual surfaces. After debonding, a single blinded operator performed the tooth surface clean-up, as commonly performed in clinical practice; without the use of fluorescent light (non-FIT) and with two methods using fluorescent light to identify composite remnants on the tooth surfaces (FIT; OPAL and BRACE). Tooth surfaces were scanned before bonding and after clean-up, and the two scans were superimposed using the best-fit method. The results showed that the debonding method, type of tooth and type of tooth surface had a significant effect on the presence of composite remnants, enamel defects, and on debonding time. Contrary to the non-FIT method, there were no composite remnants after clean-up with the use of fluorescence inducing light. Clean-up time was significantly reduced on the buccal surfaces when using the FIT methods. On the lingual surfaces, the FIT methods resulted in larger enamel defects.

Hydroxyapatite Film Coating by Er:YAG Pulsed Laser Deposition Method for the Repair of Enamel Defects

There are treatments available for enamel demineralization or acid erosion, but they have limitations. We aimed to manufacture a device that could directly form a hydroxyapatite (HAp) film coating on the enamel with a chairside erbium-doped yttrium aluminum garnet (Er:YAG) laser using the pulsed laser deposition (PLD) method for repairing enamel defects. We used decalcified bovine enamel specimens and compacted α-tricalcium phosphate (α-TCP) as targets of Er:YAG-PLD. With irradiation, an α-TCP coating layer was immediately deposited on the specimen surface. The morphological, mechanical, and chemical characteristics of the coatings were evaluated using scanning electron microscopy (SEM), scanning probe microscopy (SPM), X-ray diffractometry (XRD), and a micro-Vickers hardness tester. Wear resistance, cell attachment of the HAp coatings, and temperature changes during the Er:YAG-PLD procedure were also observed. SEM demonstrated that the α-TCP powder turned into microparticles by irradiation. XRD peaks revealed that the coatings were almost hydrolyzed into HAp within 2 days. Micro-Vickers hardness indicated that the hardness lost by decalcification was almost recovered by the coatings. The results suggest that the Er:YAG-PLD technique is useful for repairing enamel defects and has great potential for future clinical applications.

Enamel Defects Associated With Dentin Sialophosphoprotein Mutation in Mice

Dentin sialophosphoprotein (DSPP) is an extracellular matrix protein that is highly expressed in odontoblasts, but only transiently expressed in presecretory ameloblasts during tooth development. We previously generated a knockin mouse model expressing a mouse equivalent (DSPP, p.P19L) of human mutant DSPP (p.P17L; referred to as “DsppP19L/+”), and reported that DsppP19L/+ and DsppP19L/P19L mice manifested a dentin phenotype resembling human dentinogenesis imperfecta (DGI). In this study, we analyzed pathogenic effects of mutant P19L-DSPP on enamel development in DsppP19L/+ and DsppP19L/P19L mice. Micro-Computed Tomography (μCT) analyses of 7-week-old mouse mandibular incisors showed that DsppP19L/P19L mice had significantly decreased enamel volume and/or enamel density at different stages of amelogenesis examined. Acid-etched scanning electron microscopy (SEM) analyses of mouse incisors demonstrated that, at the mid-late maturation stage of amelogenesis, the enamel of wild-type mice already had apparent decussating pattern of enamel rods, whereas only minute particulates were found in DsppP19L/+ mice, and no discernible structures in DsppP19L/P19L mouse enamel. However, by the time that incisor enamel was about to erupt into oral cavity, distinct decussating enamel rods were evident in DsppP19L/+ mice, but only poorly-defined enamel rods were revealed in DsppP19L/P19L mice. Moreover, μCT analyses of the mandibular first molars showed that DsppP19L/+ and DsppP19L/P19L mice had a significant reduction in enamel volume and enamel density at the ages of 2, 3, and 24weeks after birth. Backscattered and acid-etched SEM analyses revealed that while 3-week-old DsppP19L/+ mice had similar pattern of enamel rods in the mandibular first molars as age-matched wild-type mice, no distinct enamel rods were observed in DsppP19L/P19L mice. Yet neither DsppP19L/+ nor DsppP19L/P19L mice showed well-defined enamel rods in the mandibular first molars by the age of 24weeks, as judged by backscattered and acid-etched SEM. In situ hybridization showed that DSPP mRNA level was markedly reduced in the presecretory ameloblasts, but immunohistochemistry revealed that DSP/DSPP immunostaining signals were much stronger within the presecretory ameloblasts in Dspp mutant mice than in wild-type mice. These results suggest that mutant P19L-DSPP protein caused developmental enamel defects in mice, which may be associated with intracellular retention of mutant DSPP in the presecretory ameloblasts.

Incisor- Molar Hypomineralization Phenotype Characteristics and Comparison with Amelogenesis Imperfecta: An Approach to a Differential Diagnosis

Background: Incisor-molar hypomineralization (IMH) presents various clinical characteristics that generate confusion for differential diagnosis with other enamel abnormalities such as amelogenesis imperfecta (AI). Purpose: To analyze dental, facial, and skeletal characteristics in people with IMH and compare them to those with AI in order to identify diagnostic differences between these two enamel defects. Methods: Analytical observational study. Twelve 7-to-10-year-olds with IMH and 10 8-to-49-year-olds with AI were studied. IMH was assessed according to the European Academy of Pediatric Dentistry’s diagnostic criteria, Mathu Maju’s criteria (2006), and Neeti Mittal’s phenotypic classification (2016), while Witkop’s criteria (1989) were used to analyze AI. Clinical, radiographic, facial, and skeletal analyses were performed to establish IMH phenotypes, information that was fed into an Excel® database for subsequent statistical analysis (SPSS 22.0) (p<0.05). Results: Statistically significant differences were found between IMH and AI. Only patients with IA presented dilaceration, dental agenesis, and taurodontism. There are similarities regarding facial features such as facial asymmetry, increased intercanthal distance, decreased lower third, biprochelia and convex profile, and occlusal features such as molar relationship, canine relationship, and overjet. Concerning transverse relationships, micrognathism was more frequent in IMH and in vertical relationships, deep overbite was greater in IMH than in AI. Conclusions: The main differences between IMH and AI were evident in skeletal characteristics and associated dental alterations.

Associating the Presence of Structural Defects in Dental Enamel with Children's Health History

The enamel defects, hypoplasia and hypo mineralization, are classified as dental anomalies of structure, being frequently found in deciduous and permanent dentitions, since the permanent teeth and second deciduous molars finish their total mineralization after the age of three. The aim of the present study was to identify the presence of hypo mineralization and/or enamel hypoplasia and to associate it with respiratory problems in infant patients. Of the 90 patients evaluated, it was found that 23 male children (57.5%) and 22 female children (44%) had defects in the structure of tooth enamel. Most children were born by cesarean operation (64.4%), with no complications during birth (90.0%), 12.2% of children had dental anomalies (agenesis, ectopic canine, ankylosis, fusion, conoid tooth, and macrodontia, only 7 children showed an association between dental anomalies and enamel defects. Regarding respiratory problems that occurred up to 3 years of age, 38.9% had an episode of asthma, bronchitis, sinusitis, rhinitis, or pneumonia, and 55% had similar results at the current age. There was a positive association (Chi-square tests) between the presence of changes in the structure of tooth enamel and the presence of respiratory problems up to 3 years of age (p <0.001). It is concluded, therefore, that the presence of respiratory problems in early childhood, can interfere in amelogenesis, providing disturbances for the formation of normal enamel, causing defects or irregularities in the surface of the dental enamel, such as hypoplasias and hypo mineralization. Keywords: Dental Enamel Hypoplasia. Dental Enamel. Tooth Abnormalities. ResumoOs defeitos de esmalte, hipoplasia e hipomineralização, são classificados como anomalias dentárias de estrutura, sendo encontrados com frequência nas dentições decídua e permanente, já que os dentes permanentes e segundos molares decíduos finalizam sua total mineralização após os três anos de idade. O objetivo do presente estudo foi identificar a presença de hipomineralização e/ou hipoplasia de esmalte, e associá-la com problemas respiratórios no paciente infantil. Dos 90 pacientes avaliados, constatou-se que 23 crianças do gênero masculino (57,5%) e 22 do gênero feminino (44%) apresentaram defeitos na estrutura do esmalte dentário. A maioria das crianças nasceu de parto cesária (64,4%), sem complicação no parto (90,0%), 12,2% das crianças apresentaram anomalias dentárias (agenesia, canino ectópico, anquilose, fusão, dente conóide e macrodontia), somente 7 crianças apresentaram associação entre anomalias dentárias e defeitos de esmalte. Em relação à problemas respiratórios ocorrido até aos 3 anos de idade 38,9% apresentaram algum episódio de asma, bronquite, sinusite, rinite ou pneumonia e 55% apresentaram resultados semelhantes na idade atual. Houve associação positiva (Testes Qui Quadrado) entre a presença de alterações na estrutura do esmalte dentário e presença de problemas respiratórios até os 3 anos de idade (p<0,001). Conclui-se, portanto, que a presença de problemas respiratórios na primeira infância, podem interferir na amelogênese, proporcionando distúrbios para formação do esmalte normal, causando defeitos ou irregularidades na superfície do esmalte dentário, como hipoplasias e hipomineralizações. Palavras-chave: Hipoplasia do Esmalte Dentário. Esmalte Dentário. Anormalidades Dentárias.

Minimally Invasive Dentistry for Pre-Eruptive Enamel Lesions—A Case Series

Pre-eruptive enamel lesions occur during tooth formation and include fluorosis, traumatic hypomineralization, and molar incisor hypomineralization. Minimally invasive treatment approaches, such as microabrasion, should be considered for these cases. This article presents a case series of three patients with pre-eruptive enamel defects in esthetically compromised tooth regions which were treated with the microabrasion technique: two fluorosis cases, moderate and advanced, and one hypomineralization case of traumatic etiology. In Cases 1 and 3, there was a significant improvement in esthetics with a total resolution of the enamel defects. However, a slight yellowish coloration may be detected at close observation. In Case 2 (advanced fluorosis), although there was no full resolution of the white spots, there was a clear improvement in esthetics. Microabrasion is a safe and effective, minimally invasive treatment for pre-eruptive enamel lesions. It does not require local anesthesia, it is less destructive than restorative interventions, and allows good esthetic outcomes with no significant postoperative sensitivity. Its efficacy is directly related to the lesions’ severity and depth. Although there are some limitations, further improvement can be achieved with dental bleaching. More invasive treatments might be considered if results are still unsatisfactory.

Molar and Incisor Hypomineralization

Molar and incisor hypomineralization is a developmental defect that is systemic in origin that affects one or more than one permanent first molars, and is often associated with permanent incisors. It is usually characterized by well demarcated opacities and qualitative enamel defects caused by decreased inorganic enamel components, and reduced mineralization. It can cause esthetic, functional, psychological, and behavioral problems in children. Its reported prevalence varies widely, from 2.5% to 40.2%. Multiple aspects of dental treatment for it are challenging, such as behavior management, difficulty in achieving adequate local anesthesia, tooth hypersensitivity, and retention of restorations. This review discusses the most important considerations pertaining to its prevalence, severity, etiology, differential diagnosis, and some of the challenges and treatment modalities applicable in young patients. Data is collected from PubMed, Medline, and Embase databases.