Discrepancies in growth patterns are classified into three main types of occlusion, determined when the jaws are closed and the teeth are held together. In class I (normal) occlusion, the cusps of the posterior mandibular teeth interdigitate ahead of and inside the corresponding cusps of the opposing maxillary teeth. This relationship provides a normal facial profile. In class II occlusion, “buck teeth”, the cusps of the posterior mandibular teeth are behind and inside the corresponding cusps of the maxillary teeth. This common occlusal disharmony is found in approximately 45% of the population. The facial profile may give the appearance of a "receding chin" (retrognathia) or protruding front teeth. The resultant increased space between upper and lower anterior teeth encourages finger sucking and tongue-thrust habits. Additionally, children with pronounced class II occlusions are at greater risk of damage to the incisors due to trauma. In class III occlusion, “underbite”, the cusps of the posterior mandibular teeth interdigitate a tooth or more ahead of their opposing maxillary counterparts. The anterior teeth appear in “cross-bite”, with the mandibular incisors protruding beyond the maxillary incisors. The facial profile gives the appearance of a "protruding chin" (prognathia).
Normally, the mandibular teeth are in a position just inside the maxillary teeth, so that the outside mandibular cusps or incisal edges meet the central portion of the opposing maxillary teeth. A reversal of this relation is referred to as a cross-bite. Cross bites may be anterior, involving the incisors; posterior, involving the molars; or may involved single or multiple teeth.
If the posterior mandibular and maxillary teeth make contact with each other but the anterior teeth are still apart, the condition is called an open bite. Open bites may be due to skeletal growth pattern or digit sucking. With prolonged digit sucking, the open bite may not resolve. If mandibular anterior teeth occlude inside the maxillary anterior teeth in an over-closed position, the condition is referred to as a closed or deep bite. Treatment of open and closed bites consists of orthodontic correction, generally performed in the pre-teen or teenage years.
Overlap of incisors can result when the jaws are too small or the teeth are too large for adequate alignment of the teeth. Growth of the jaws is mostly in the posterior aspects of the mandible and maxilla, and therefore inadequate space for the teeth at 7 or 8 years of age will not resolve with growth of the jaws. Spacing in the primary dentition is normal and favorable for adequate alignment of successor teeth.
Prolonged digit sucking can cause flaring of the maxillary incisor teeth and an open bite. The prevalence of digit sucking decreases steadily from the age of 2 years to approximately 10% by the age of 5. The earlier the habit is discontinued after the eruption of the permanent maxillary incisors (age 78), the greater the likelihood that there will be lessening of the incisors flaring and bite opening. A variety of treatments have been suggested, from behavioral modification to insertion of an appliance with extensions that serves as a reminder when the child attempts to insert the digit. The greatest likelihood of success occurs in cases in which the child desires to stop. Stopping of the habit, however, will not rectify a malocclusion caused by a deviant growth pattern.
Dental Caries (Cavities):
The development of dental caries is dependent upon the relationships among the tooth surface, dietary carbohydrates, and specific oral bacteria. Organic acids produced by bacterial fermentation of dietary carbohydrates reduce the pH of dental plaque adjacent to the tooth to a point where demineralization occurs. The initial carious lesion appears as an opaque white spot on the enamel, and, with progressive loss of tooth mineral, cavitation occurs.
Current knowledge indicates that a group of microorganisms, mutans streptococci, are associated with the development of dental caries on the enamel surface. These bacteria have the ability to adhere to enamel, produce abundant acid and survive at low pH. Demineralization from acid production is determined more by the frequency of carbohydrate consumption than by the actual quantity of carbohydrate eaten. For example, cariogenic potential of a nursing bottle of apple juice that is consumed throughout the night or at nap times, is much greater than that of the same volume of apple juice consumed at a single meal. Additionally, sugar retained orally for long periods (e.g., sucrose in sticky candies) is more cariogenic than that in food products retained for short times.
Rampant caries in infants and toddlers, referred to as Early Childhood Caries (ECC), Nursing Bottle Caries and Baby Bottle Tooth Decay, has in the past been ascribed solely to inappropriate bottle feeding. While the combination of a child being infected with cariogenic bacteria and the frequent ingestion of sugar, either in the bottle or in solid foods, are critical, other factors such as enamel hypoplasia of primary teeth due to nutritional deficiencies during pregnancy or premature birth may play a role. Reports have also associated “at will” breast feeding with caries of the maxillary anterior teeth, but the possibility of cariogenic dietary practices other than breast feeding, in such cases, needs further exploration.
If left untreated, dental caries usually destroy most of the tooth and invade the dental pulp, leading to an inflammation of the pulp (pulpitis) and significant pain. Pulpitis can progress to necrosis, with bacterial invasion of the alveolar bone (dental abscess; periapical abscess). This process may lead to sepsis and facial space infection. Such periapical infection of a primary tooth also may disrupt normal development of the successor permanent tooth.
Dental treatment can restore many teeth affected with dental caries using silver amalgam or plastic restorations and crowns. If caries involves the dental pulp, a partial removal of the pulp (pulpotomy) or complete removal of the pulp (pulpectomy) may be required. If a tooth requires extraction, a space maintainer to prevent migration of teeth may be indicated to prevent impaction or malposition of permanent successor teeth.
Fluoride. The most effective preventive measure against dental caries is optimizing the fluoride content of communal water supplies to one part per million. In fluoride-deficient water supplies similar caries prevention benefits are obtained from dietary fluoride supplements (see below table). The fluoride level of a water supply can usually be obtained by calling the local public health department. If a private water supply is used, it is necessary to get the water tested for fluoride levels before fluoride supplements are prescribed. To avoid potential overdoses, no fluoride prescription should be written for more than a total of 120 mg of fluoride. Significant overdose of fluoride (greater than 5 mg/kg) needs immediate medical attention. The use of topical fluoride agents, applied professionally or by the patient, also are beneficial to children at risk for caries.
Supplemental Fluoride Dosage Schedule:
Fluoride in Home Water (ppm)
|6 mos.-3 yrs.
*mg fluoride per day
Oral Hygiene. Thorough daily brushing and flossing of the teeth may help prevent dental caries and periodontal disease. Studies have shown that most children under 8 years of age do not have the coordination required for adequate oral hygiene. Accordingly, parents should assume responsibility for the child's oral hygiene, with the degree of parental involvement appropriate to the child's changing abilities.
Diet. Decreasing the frequency of sugar ingestion prevents dental caries. Therefore using sweetened beverages in the nursing bottle and bedtime nursing bottles should be discouraged, and children at risk for dental caries should reduce between-meal sugar containing snacks.
Dental Sealants. Plastic dental sealants have been shown to be effective in the prevention of pit and fissure caries. Sealants are most effective when placed soon after the teeth erupt (usually within 12 years) and when used in children with deep grooves and fissures in the molar teeth.
Gingivitis. Poor oral hygiene results in the accumulation of a dental plaque at the tooth-gingival interface that activates an inflammatory response, expressed as localized or generalized reddening and swelling of the gingiva. In severe cases the gingiva spontaneously bleeds and there is oral malodor. Treatment is with proper oral hygiene (careful tooth brushing and flossing), and complete resolution can be expected.
Teething. Teething can lead to intermittent localized discomfort in the area of erupting primary teeth, irritability, low-grade fevers and excessive salivation; yet, many children have no apparent difficulties. Symtomatic treatment includes chewing on ice rings and oral analgesics . Similar manifestations can also arise when the first permanent molars erupt at about age 6.
|Injuries to Teeth:
Approximately 10% of children between 18 months and 18 years of age will sustain significant tooth trauma. There appear to be three age periods of greatest predilection: (1) toddlers (13 years), usually due to falls or child abuse; (2) school aged (710 years), usually from bicycle and playground accidents; and (3) adolescents (1618 years), often the result of fights, athletic injuries, and automobile accidents. Injuries to teeth are much more frequent among children with protruding front teeth.. Children with craniofacial abnormalities or neuromuscular deficits are also at increased risk for dental injury. Injuries to teeth may involve the hard dental tissues, the dental pulp (nerve) and injuries to the periodontal structure (surrounding bone and attachment apparatus).
Fractures of teeth may be uncomplicated (confined to the hard dental tissues) or complicated (involving the pulp). Exposure of the pulp will result in its bacterial contamination, which can lead to infection and pulp necrosis. Pulp exposure complicates therapy and may lower the likelihood of a favorable outcome.
Trauma to the mouth most often affects the crowns or roots of the maxillary incisor teeth. Uncomplicated crown fractures are treated by covering exposed dentin and by placing an esthetic restoration. Complicated crown fractures usually require endodontic (root canal) therapy. Crown-root fractures and root fractures usually require extensive dental therapy. Such injuries in the primary dentition may interfere with normal development of the permanent dentition, and therefore, these types of injuries to the primary incisor teeth usually are managed by extraction of the fractured segments.
Injuries resulting in fractured teeth should be referred to a dentist as soon as possible. Furthermore, even when dentition appears intact following oral trauma, the patient should be evaluated promptly by a dentist. Baseline data (radiographs, mobility patterns, responses to specific stimuli [percussion, electricity, hot, and cold]) enables the dentist to assess the likelihood of future complications.
If a permanent tooth that has been knocked out is replanted within 20 minutes after injury, good success may be achieved; whereas if the delay exceeds 2 hours, the failure (root resorption, ankylosis) is frequent. The likelihood that normal reattachment will follow replantation of the tooth is related to the viability of the periodontal ligament. Parents confronted with this emergency situation should:
1. Find the tooth.
2. Rinse the tooth. (Do not scrub the tooth. Do not touch the root. After plugging the sink drain, hold the tooth by the crown and rinse it under running tap water.)
3. Insert the tooth into the socket. (Gently place it back into its normal position. Do not be concerned if the tooth extrudes slightly. If the parent or child is too apprehensive for replantation of the tooth, the tooth should be placed in cow's milk. Milk as transport medium maintains periodontal ligament viability.)
4. Go directly to the dentist. (In transit, the child should hold the tooth in place with a finger. The parent should buckle a seatbelt around the child and drive safely.)
After the tooth is replanted, it must be immobilized (acrylic splint) to facilitate reattachment; endodontic therapy is always required. The initial signs of complications associated with replantation may appear as early as 1 week post-trauma or as late as several years later. Close dental follow-up is indicated for at least 1 year.
To minimize the likelihood of dental injuries:
1. Every child or adolescent who engages in contact sports should wear a mouth guard, which may be constructed by a dentist or purchased at any athletic goods store.
2. Helmets with face guards should be worn by children or adolescents who are riding a bike, skating, or using a skateboard. Additionally, children with neuromuscular problems or seizure disorders may need to use a helmet to protect the head and face during falls..
3. All children or adolescents with protruding incisors should be evaluated by a pediatric dentist or orthodontist.