DCA06DT Dental Treatment of Pediatric and Adolescent Patients _ __________________________________
by bacteria that can initiate the carious process. Consultation with a dentist or pedodontist can determine the best protocol by which this is accomplished. These teeth are extracted if the mobility presents a risk of aspiration, but this is rare. The chronology of the eruption of the 20 deciduous teeth will vary widely among children. The mandibular central incisors are usually the first teeth to erupt at 6 to 10 months of age. The maxillary and mandibular second molars complete the sequence and usually appear at 23 to 33 months of age [2]. The lateral incisors, canines, and first molars erupt in the intervening interval. Genetics, systemic illness, and develop- mental problems are among the many factors that can delay the eruption of the deciduous teeth. Unlike their permanent counterparts, deciduous teeth have no premolars. The permanent premolars replace the first and second deciduous molars and are the only permanent teeth to have less length in a mesial-to-distal (anterior-to-posterior) dimension than their deciduous predecessors. The permanent molars are the only permanent teeth that do not replace a pre- existing deciduous tooth. The eruption sequence of permanent teeth can also vary. The mandibular central incisors and the mandibular and maxillary first molars are the first permanent teeth to erupt, usually at 6 to 7 years of age. The maxillary and mandibular second molars erupt between 12 and 13 years of age. The third molars are unpredictable but may appear at 17 to 21 years of age, the last teeth to fully erupt during adolescence [3]. Many genetic and physiologic factors can accelerate or extend these eruption patterns. Teething pain can cause infants and toddlers to drool, become restless and irritable, and even develop a low-grade fever, with treatment designed to palliate symptoms. Caution should be exercised if over-the-counter topical anesthetic preparations are used, as even small doses of these drugs can be toxic to infants and toddlers if swallowed. Similarly, the use of any analgesic medication should be minimized to reflect the limited abil- ity of the infant or toddler to metabolize these substances. Consultation with a pedodontist or pediatrician is advisable to determine a dosing schedule that is efficacious and safe.
Proportionately, the relationship of the mesial-to-distal dimensions of the crowns of deciduous teeth to the occlusal to gingival dimension is greater than the same relationship among permanent teeth. The occlusal table of the deciduous molars, upon which grinding and crushing of food occurs, is more narrow compared with the wide occlusal tables of the permanent molars. Deciduous molars also feature a prominent bulge in the mesio-buccal area near the gingival crest, which can be conducive to the retention of bacterial plaque at the gingival level and which poses a greater risk of the develop- ment of caries [4]. The roots of deciduous anterior teeth are more narrow in a mesial-to-distal direction compared to those of the anterior permanent teeth. The crown-to-root length ratio of deciduous molars is less than the same ratio in the permanent molars, as the roots of deciduous molars are longer in relation to the size of the crowns of these teeth. The apical anatomy of the decidu- ous molars can feature pronounced but slender curvatures that should be considered if the teeth must be extracted. The roots of the deciduous molars surround the crowns of the developing permanent maxillary and mandibular bicuspids. If an extrac- tion is indicated for any of the deciduous molars, care must be taken to avoid damage to the crowns of their permanent successors. Deciduous molars with fully formed roots can be challenging extractions. These slender and curved roots cannot withstand the degree of pressure utilized for the extractions of permanent molars and can fracture easily if excessive pressure is applied. Deciduous molar roots that fracture in the apical area may be difficult to locate and remove without damaging the permanent bicuspids. When the roots of the deciduous teeth lose their normal means of attaching to the bone via the periodontal ligament and become fused directly to the bone, this is called ankylosis [5]. Although ankylosis can affect any deciduous tooth, the molars are most often involved. Ankylosis interferes with the normal process of deciduous root dissolution to allow for the normal sequence of shedding of the deciduous teeth and replacement by the permanent teeth. Ankylosed teeth have a dull sound when they are percussed with an instrument and a submerged appearance when adjacent non-ankylosed decidu- ous teeth are shed and the permanent successors erupt into their proper position. They can delay the eruption of their permanent successor and allow for the unintentional drifting of the adjacent teeth or hypereruption of the opposing tooth. These problems can lead to functional and cosmetic problems that require orthodontic correction. Ankylosed teeth can be difficult extractions because they are fused directly to the bone and excessive pressure can lead to fracture of the deciduous roots, the supporting alveolar bone, and the developing per- manent tooth.
ANATOMY AND MORPHOLOGY OF DECIDUOUS TEETH
The 20 deciduous teeth have pronounced differences in the anatomy of their crowns and roots and in the structure and amounts of enamel, dentin, and pulp chamber compared to those of the permanent teeth. These morphologic differences reflect the teeth’s design to function for a limited period of time and to be aligned into maxillary and mandibular arches of small dimensions. These differences will also influence the progression of the carious process and the manner in which carious deciduous teeth are restored.
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