Key points

Introduction

Dental caries in the primary dentition prior to age 6 years is the most common chronic condition among children in the United States. Over the past several decades, dental caries experience in children has focused predominantly on early childhood caries (ECC). ECC, formerly known as nursing bottle caries, baby bottle tooth decay, night bottle mouth, and night bottle caries, is defined as a dental disease that affects children between birth and age 6 years. ECC is characterized by the presence of 1 or more decayed (noncavitated or cavitated lesions), missing (due to caries), or filled tooth surfaces in any primary tooth. The life cycle of the primary dentition begins to emerge at approximately age 6 months, with the eruption of the mandibular central incisors, and concludes with the exfoliation of the primary maxillary canines at approximately 12 years of age. There has been little focus on the caries experience in the primary dentition beyond 6 years of age. This article highlights 2 additional dental caries patterns presenting in the primary dentition along with their prevention and management strategies.

Redefining caries patterns in the primary dentition

The classic clinical presentation of ECC early in life involves carious involvement of the 4 maxillary incisors with or without involvement of the first primary molars because these teeth are in the pathway of exposure to sugar-containing liquids, including breastmilk and infant formulas. The position of the tongue while breastfeeding or drinking from a bottle or sippy cup blankets the lower incisors and prevents any sugar-containing liquid from coming into contact with these teeth. This pattern typically presents itself prior to the age of 3 years (Martha Ann Keels, DDS, PhD, Erica A. Brecher, DMD, MS, Unpublished Data, 2019). In other words, from clinical experience, if a child reaches the age of 36 months without experiencing any carious lesions affecting the maxillary incisors, then it is highly unlikely these maxillary anterior teeth will become carious. Another important observation involving the first primary molar in the ECC pattern is that the carious process typically starts on the occlusal surface and can spread laterally onto the mesial and/or distal surfaces. If diagnosed early, then the remaining dentition can be protected as the primary canines and primary second molars erupt after the first molars. In most children, infant and toddler feeding behaviors (eg, breastfeeding or bottle feeding through the night) contributing to ECC have ceased prior to the eruption of the primary canines and second primary molars. Thus, age 3 years is a natural cutoff for redefining ECC, based on the significant contribution of infant and toddler feeding to this disease pattern as well as a child’s transition to a school setting at age 4 years.

In a retrospective chart review of 25 years in a private pediatric dental practice in an urban community providing dental care for more than 6000 children ages birth to 21 years (70% with private dental coverage and 30% with Medicaid coverage), 3 distinct dental caries patterns were observed in the primary dentition (Martha Ann Keels, DDS, PhD, Erica A. Brecher, DMD, MS, Unpublished Data, 2019) ( Fig. 1 ); 25% of the children had dental caries involving the 4 maxillary incisors with or without involvement of the maxillary first primary molars ( Fig. 2 ). All of these children were predominantly under the age of 3 years. The second pattern affecting most of the children was interproximal dental caries involving the distal surface of the first primary molars and the mesial surface of the second primary molars ( Fig. 3 ); 70% of the children with dental caries presented with this pattern. The third pattern, which was the least prevalent, occurring less than 5% of the time, was dental caries associated with enamel hypoplasia of the 4 primary second molars ( Fig. 4 ). There were some children older than 3 years of age, who had not seen a dentist, who were diagnosed with various combinations of the 4 patterns of dental caries. This article focuses on the predominant 3 patterns observed.

Primary dental caries patterns.

Example of Classic ECC, where the primary maxillary incisors and first molars are affected.

Right and left bitewing radiographic example of LCC in a 4 year old, where 8 interproximal surfaces are carious. No other lesions were detected.

Example of PSMH-C. The arrows point to the affected second molars.

(Copyright © American Academy of Pediatric Dentistry and reproduced with their permission.)

In this private practice setting, the classic presentation of ECC occurred prior to the age of 3 years. A majority of children presenting with LCC had not experienced ECC prior to developing the posterior interproximal disease. For purposes of this article, ECC is redefined to match more closely the disease pattern that it was meant to reflect (nursing bottle caries, baby bottle tooth decay, night bottle mouth, and night bottle caries), thus limiting ECC from birth to the age of 3 years. This revised classification allows for a more precise and targeted approach to disease prevention and management. Having the ECC definition extend beyond age 3 years masks the ability to recognize and study other dental caries patterns occurring in the primary dentition.

The most prevalent dental caries pattern in the primary dentition, observed in the private practice setting 70% of the time, initiated after the closure of the proximal contacts between the first and second primary molars. This disease pattern is now referred to as late childhood caries (LCC). There are potentially 8 interproximal lesions that can occur with LCC. The lesions can vary in depth on each surface. It is possible that a practitioner diagnoses LCC with the initial presentation of 1 interproximal surface affected or any combination all the way up to involving all 8 surfaces. The severe form of LCC has, in addition to interproximal caries between the primary molars, dental caries involvement of the mesial of the first primary molars and the distal of the primary canines, resulting in, potentially, 16 interproximal lesions. A child manifesting severe LCC generally is characterized by severe dental crowding and lack of developmental spacing between the posterior teeth. The timing of the physiologic closure of the contact between the first and second primary molars is approximately age 4 years. A primary dentition that maintains the developmental spacing is less likely to develop LCC. An important observation that distinguishes LCC from ECC is the progression of the carious process involving the first primary molars. In LCC, the carious lesion starts at the contact area and, as the lesion progresses and cavitates, the marginal ridge is undermined and the lesion is visualized occlusally. With ECC, the carious lesion involving the first primary molars initiates occlusally and spreads laterally to the proximal surfaces, the exact opposite of LCC.

The third unique pattern that presented in the private practice setting was carious involvement subsequent to enamel hypoplasia affecting the second primary molars. In most cases, the children with primary second molar hypoplasia (PSMH) had no other dental caries experience. This pattern is apparent after the second primary molars emerge through the gingiva at approximately ages 23 months to 33 months. If PSMH has carious involvement it is referred to as PSMH with caries involvement (PSMH-C) versus PSMH with noncarious involvement.

Recognizing which dental caries pattern exists in a child is a first critical step in formulating the best strategy for management of the disease as well as developing the most effective preventive plan.