Hypoplasia or Hypomineralisation Patel et al 2019 PDF

VERIFIABLE CPD PAPER Paediatric dentistry CLINICAL Hypomineralisation or hypoplasia? Ayesha Patel,*1 Sahar Aghababaie1 and Susan Parekh1 Key points Provides gene...

VERIFIABLE CPD PAPER Paediatric dentistry CLINICAL Hypomineralisation or hypoplasia? Ayesha Patel,*1 Sahar Aghababaie1 and Susan Parekh1 Key points Provides general dental practitioners with an Outlines the different characteristics and clinical Provides an understanding of how to diagnose overview of the background and aetiology of variabilities between hypomineralisation and hypomineralisation and hypoplasia and a guide to enamel hypomineralisation and hypoplasia. hypoplasia. its management. Abstract Enamel hypomineralisation is a qualitative defect, with reduced mineralisation resulting in discoloured enamel in a tooth of normal shape and size. Because the enamel is weaker, teeth can undergo post eruptive breakdown, resulting in missing enamel. Enamel hypoplasia is a quantitative defect of the enamel presenting as pits, grooves, missing enamel or smaller teeth. It can sometimes be difficult to differentiate between the two. In this review paper, we aim to explain the importance of differentiating between the two conditions, and how to manage patients presenting with enamel defects. How does enamel form? occurs during the mineralisation or maturation can appear opaque, creamy white or have phase, it is called hypomineralisation. Often yellow/brown discolourations. Opacities Enamel is produced by specialised end- the cause is difficult to determine. may be diffuse and/or demarcated. Figure 1 differentiated cells known as ameloblasts.1 The The psychological impact of enamel defects demonstrates the appearance of generalised formation of enamel can be separated into in children should not be underestimated, and diffuse opacities. initial stages which involve secretion of matrix it is important to be aware of the impact of Hypomineralised defects can be localised or proteins such as amelogenin, ameloblastin and being teased for having different looking teeth. generalised. Local hypomineralised defects can enamelin, and later stages of mineralisation and Dental appearance influences how individuals be caused by trauma or infection to the primary maturation.1 are perceived by others and young people make tooth, or radiation. Generalised hypomineralised Tooth enamel is unique due to its high mineral negative psychosocial judgements on the basis defects are often caused by systemic, content. It is composed of highly organised, of enamel appearance.3 environmental or genetic factors as described tightly packed hydroxyapatite crystallites in Table 1. Systemic/environmental attacks that that comprise 87% of its volume and 95% of What is hypomineralisation and occur in a specific window of time will only affect its weight, with the remainder comprising hypoplasia? teeth mineralising during that period, as seen in of organic matrix and water.1 This pattern of chronological hypomineralisation. Fluorosis can organisation and mineralisation gives enamel Hypomineralisation: cause enamel hypomineralisation which can be its significant physical properties, making it the A reduced quality of enamel is termed either localised or generalised and presents as hardest tissue in the body.1 hypomineralisation. The enamel is of diffuse, linear or patchy white opacities without Developmental defects of enamel are normal thickness, but not fully mineralised. a clear boundary. Patients with amelogenisis not uncommon, both in the primary and Enamel hypomineralisation can be seen imperfecta can present with hypomineralised or permanent dentitions.1 Environmental and/ due to differences in translucency; enamel hypoplastic defects which tend to be generalised. or genetic factors that interfere with tooth formation are thought to be responsible for both hypomineralisation and hypoplasia.1,2 If a disturbance occurs during the secretion phase, the enamel defect is called hypoplasia. If it 1 Paediatric Dentistry, Eastman Dental Hospital, London, United Kingdom *Correspondence to: Ayesha Patel Email: [email protected] Refereed Paper. Accepted 24 May 2019 https://doi.org/10.1038/s41415-019-0782-9 Fig. 1 Enamel hypomineralisation showing generalised diffuse opacities affecting anterior incisors BRITISH DENTAL JOURNAL | VOLUME 227 NO. 8 | October 25 2019 683 © The Author(s), under exclusive licence to British Dental Association 2019  CLINICAL Paediatric dentistry The most common hypomineralisation Table 1 Aetiology of enamel hypoplasia and hypomineralisation1,2,4 defect seen in children is molar incisor Aetiology Hypomineralisation Hypoplasia hypomineralisation (MIH), which affects the Local first permanent molar teeth and often the Trauma □ □ permanent incisors.2,4 The pooled prevalence of MIH is 14.2% globally.5 There is an association Infection □ □ between MIH and hypomineralisation affecting Radiation □ x the second primary molars.6 MIH can vary in Systemic presentation, from small areas of discolouration Neonatal - hypocalcemia, hypoxia, severe infection □ x to extensive post eruptive breakdown (PEB). PEB can occur rapidly causing sensitivity or pain Premature birth weight □ □ and caries can be difficult to restore.4 Enamel Postnatal – infections associated with high fever, multiple ear/ throat infections, frequent antibiotic usage in early childhood □ x missing due to PEB tends to leave rough, uneven border between the affected and unaffected Childhood oncology □ x enamel. In comparison enamel missing due to Coeliac disease □ x hypoplasia is often smooth with rounded edges. Renal disease & nephrotic syndrome x □ The severity of hypomineralisation is usually less in affected incisors compared to affected Vitamin D deficiency x □ molars, but aesthetic concerns may be an issue. Environmental Fluorosis □ x Hypoplasia: Idiopathic Enamel hypoplasia is a reduced quantity of enamel which results in irregular shaped teeth, Molar Incisor Hypomineralisation (MIH) □ x which may be pitted, thinner or smaller in size Genetic (Fig. 2). Localised hypoplastic defects can be Amelogenesis Imperfecta □ □ caused by trauma or infection in the primary tooth. Generalised hypoplastic defects can also be due to systemic, environmental and genetic factors. The most common cause of chronological hypoplasia seen in children is due to vitamin D deficiency. 1 Chronological hypoplasia is a generalised form of hypoplasia, with a characteristic presentation of symmetrical defects. The chronological pattern is seen only in parts of the teeth developing at the time of the insult affecting enamel secretion. In chronological hypoplasia, the border is smooth Fig. 2 Enamel hypoplasia with pitting and rounded, as opposed to the rough border in PEB, and only affects a portion of the crown, as shown in Figure 2 and Figure 3. It is important to be aware of the different aetiological factors for enamel hypomineralisation and hypoplasia to aid diagnosis, as highlighted in Table 1. Hypomineralised and hypoplastic teeth show a spectrum of clinical variability. To help recognise the difference between the two, the most common characteristics are outlined in Table 2. How does the management differ? Underst anding t he prop er t ies of hypomineralised and hypoplastic teeth Fig. 3 Chronological hypoplasia is fundamental in improving restorative outcomes. 684 BRITISH DENTAL JOURNAL | VOLUME 227 NO. 8 | October 25 2019 © The Author(s), under exclusive licence to British Dental Association 2019  Paediatric dentistry CLINICAL Patients often complain of sensitivity (PMC) or resin-modified GIC. The complete such as onlays or crowns are a treatment with both hypomineralised and hypoplastic coverage of a PMC reduces sensitivity, prevents option, the extent of sound enamel should be teeth. Simple measures to manage sensitivity cusp fracture and helps maintain occlusal carefully considered as this can have a direct include advising patients to use warm water vertical dimension and crown height 1 (Fig. 7). effect on bonding. Enamel deproteinisation during toothbrushing, using sensitive fluoride An additional benefit is that the technique is with 5% NaOCl before an adhesive application toothpaste, professional application of topical conservative with minimal removal of tooth procedure has been suggested to enhance fluoride varnish or provision of Tooth Mousse. structure. In younger patients it can be used bonding performance of resin dental adhesives Figure 4 and Figure 5 summarise the treatment as an interim restoration while waiting for to hypomineralised enamel.10 If onlays are to options for anterior and posterior teeth. optimal timing of extractions of poor prognosis be placed, gold/nickel, chromium/cobalt, first permanent molars. If indirect restorations or chromium are the materials of choice as Hypomineralised Hypomineralised teeth are more prone to Table 2 Characteristics of enamel hypoplasia and hypomineralisation1,2,4,7 dental caries, post-eruptive breakdown Characteristic Hypoplasia Hypomineralisation and often require complex restorations and therefore management is challenging.1 Pitted enamel □ x White to yellow opacities x □ Anterior teeth Hard enamel □ x It is important to consider that it is sometimes difficult to achieve direct adhesion with Soft, porous enamel x □ composite resin to teeth with poorly mineralised Poor quality enamel x □ enamel.1,7,8 In addition to this, hypomineralised Reduced amount of enamel □ x teeth are often a normal shape and size, therefore tooth preparation will be required to create a Bonding affected x □ normal emergence profile and tooth morphology. Therefore, conservative management including Fig. 4 Treatment options for anterior teeth1,4,7 tooth whitening and microabrasion should always be considered initially as a less invasive Anterior Teeth treatment modality (Figs 6a and 6b). Another micro-invasive alternative is resin infiltration. It can be used to treat white spots in vestibular Hypomineralisation Hypoplasia areas. The principle is that air and water Prevention/desensitisation entrapments in the tooth have a lower refractive Fluoride varnish (2.2% NaF-) 3-6 monthly Restorable? Duraphat ® toothpaste (age 10+ Restorable? index than intact tooth structure which leads to 2,8000ppm, age 16+ 5,000ppm unaesthetic discolorations. Resin infiltration Fluoride mouthwash (225ppm F) Yes No Tooth Mousse ® Yes Yes balances out this difference and the appearance blends in with the healthy enamel masking the whitish appearance of the lesions. Microabrasion Planned extraction Composite Restoration Planned extraction Vital Bleaching with orthodontic input with orthodontic Composite Restoration input Posterior teeth It is important to assess the prognosis of affected molar teeth, when deciding the most appropriate treatment. If a permanent molar is minimally Fig. 5 Treatment options for posterior teeth1,4,7,9 affected, with no symptoms or post eruptive Posterior Teeth breakdown, simple preventive measures such as fluoride varnish and fissure sealants are suitable. If the patient is un-cooperative or has sensitivity Hypomineralisation Hypoplasia glass-ionomer cement (GIC) fissure sealants can Prevention be considered.9 Fluoride varnish (2.2% NaF-) 3-6 It is important to assess the long-term monthly Restorable? Duraphat ® toothpaste (age 10+ Restorable? prognosis of the first permanent 2,8000ppm, age 16+ 5,000ppm molars in MIH before ten years of age. Fluoride mouthwash (225ppm F) Yes No Yes No Tooth Mousse ® Severely hypomineralised teeth of poor prognosis should ideally be managed by a Fissure sealant (resin/GIC) Planned extraction Fissure sealant (resin/GIC) Planned extraction multidisciplinary team, including a specialist Pre-formed metal crown with orthodontic input Composite Restoration with orthodontic input paediatric dentist and orthodontist, to consider Indirect restoration Pre-formed metal crown (onlay/crown) Indirect restoration planned extractions if appropriate. Molars can (onlay/crown) be stabilised with a preformed metal crown BRITISH DENTAL JOURNAL | VOLUME 227 NO. 8 | October 25 2019 685 © The Author(s), under exclusive licence to British Dental Association 2019  CLINICAL Paediatric dentistry they require minimal preparation and are such as vital bleaching, microabrasion and concern for the patient. The addition of direct conservative to tooth tissue. resin infiltration are not usually appropriate, composite restorations is straight forward, as the main issue is shape and not colour. often no preparation is required to restore the (ii) Hypoplasia tooth to its normal morphology. Hypoplastic teeth may present with pits or Anterior teeth have a reduced thickness but the quality of If the teeth are asymptomatic and the patient Posterior teeth the enamel is not altered, therefore bonding has no aesthetic concerns, then no treatment If posterior teeth are minimally affected should be unaffected. However, there is limited is necessarily indicated. However, hypoplastic fissure sealants or composite restorations are evidence to support this at present.4 Options teeth can appear smaller and be an aesthetic suitable. If the patient is uncooperative or has extreme sensitivity, GIC fissure sealants can be considered.9 If the whole tooth surface is significantly affected preformed metal crowns, composite restorations or adhesive onlays can be considered. Severely affected hypoplastic teeth of poor prognosis, should be managed by a multidisciplinary team and assessed by a specialist paediatric dentist and orthodontist to consider planned extractions if appropriate. Conclusion Correct diagnosis in patients presenting with enamel defects is crucial to indicate appropriate management. Preventative measures including fluoride treatments and fissure sealants can reduce sensitivity, and minimally invasive treatment options should be used where possible to preserve tooth structure. Fig. 6 (a) Patient with molar incisor hypomineralisation prior to microabrasion and vital bleaching (b) Post microabrasion and vital bleaching References 1. Seow W K. 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