Pediatric Restorative Dentistry
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CARIES RISK
Patients are not born with caries-inducing oral streptococci. These bacteria are introduced shortly after the first deciduous tooth appears, usually a gift from a family member. A patient’s caries risk will affect treatment and recall schedules. The following would classify a patient as high risk:
- Children with high levels of cariogenic bacteria.
- Children with dietary risk (high frequency of consumption of fermentable carbohydrates).
- Children with orthodontic appliances.
- Children who are unable to clean their teeth properly.
- Children with reduced salivary flow.
- Children with family members with a history of extensive caries.
- Children with active caries, or history of caries (strongest risk factor).
Early childhood caries (ECC) is defined as the presence of one or more decayed (non-cavitated or cavitated lesions), missing (due to caries), or filled tooth surfaces in any primary tooth in a child under the age of six. It was once known as baby bottle caries or nursing bottle caries. It appears as cavitated maxillary anterior teeth and primary molars. The tongue covers the mandibular teeth and they appear relatively unaffected. The patient is often put to bed with a sugary drink.
To decrease the risk, the American Academy of Pediatric Dentistry (AAPD) encourages professional and at home preventive measures that include:
Avoiding frequent consumption of liquids and/or solid foods containing sugar, in particular:
- sugar-sweetened beverages (e.g., juices, soft drinks, sports drinks, sweetened tea) in a baby bottle or no-spill training cup.
- ad libitum breast-feeding after the first primary tooth begins to erupt and other dietary carbohydrates are introduced.
- baby bottle use after 12-18 months.
Implementing oral hygiene measures no later than the time of eruption of the first primary tooth. Toothbrushing should be performed for children by a parent twice daily, using a soft toothbrush of age-appropriate size. In children under the age of three, a smear or rice-sized amount of fluoridated toothpaste should be used. In children ages three to six, a pea-sized amount of fluoridated toothpaste should be used.
Providing professionally-applied fluoride varnish treatments for children at risk for ECC.
RESTORATIVE PROCEDURE FOR PRIMARY TEETH
The depth of preparation is often dictated by the extent of caries, but optimally it is only 0.5mm into the dentin, 1.5mm if enamel is included. The No. 330 bur is often used with its length of 1.5mm. The No. 245 bur with a length of 3.0mm is also commonly used. Other restorative principles are followed:
- Rounded internal line angles to reduce internal stress.
- Include susceptible pits and fissures.
- Class II preps minimally breaks contacts.
- Buccal and lingual walls converge occlusally for retention.
- Isthmus width is kept to one third of intercuspal distance.
- The cervical constriction needs special attention.
- The gingival margin is not beveled (enamel rods in this area incline occlusally).
Points to remember for restoring deciduous teeth with composite:
- Conservative preparations with less emphasis on macro mechanical retention.
- May not need to include susceptible pits and fissures in prep if fissure sealant is used.
- Maintain moisture control.
Points to remember for restoring posterior deciduous teeth with stainless steel crowns:
- Associated with longevity, most likely to last until the tooth will erupt and therefore suggested in a number of cases as the gold standard.
- Indicated for teeth with extensive caries, pulpectomy or pulpotomy, malformed teeth (Amelogenesis or dentinogenesis imperfecta), or high caries risk patients, or teeth requiring multi-surface restorations.
- Not suitable when aesthetics is essential, teeth are close to exfoliating (just extract), lack of retention, as a permanent solution for permanent teeth.
- Can be used on young permanent teeth as a semi-permanent restoration.
- Occlusal cusp reduction of 1.0-1.5mm, mesial and distal reduction to the gingival level but buccal and lingual surfaces are usually left unprepared.
Points to remember for restoring anterior deciduous teeth:
- Small Class III or Class IV lesions may be restored with composite.
- If a celluloid crown form is used it requires extra reduction and retentive features (caries removal + interproximal reduction + undercut around the tooth).
- The dental board may recommend a stainless steel crown for heavily damaged anterior teeth, though in the real world you wouldn’t do this. You can veneer the crown with composite.
PULPAL TREATMENTS FOR PRIMARY TEETH
When the pulp is involved there are the usual pulpal therapies available:
- pulp capping.
- pulpotomy.
- pulpectomy, root canal treatment.
- extraction.
Pulp therapies are not suitable for kids with serious illness, such as cancer patients or those with immunocompromised situations, since there is a risk of pulp therapy failure. It is also not suggested if the tooth is mobile or if there is furcation involvement. In the real world, extraction and space maintenance is more likely than extensive pulp therapy on deciduous teeth.
The topic of indirect pulp capping procedures on primary teeth causes a lot of debate. The indications for treatment and clinical process are similar for deciduous and adult teeth.
- Indications – the tooth must be symptom-free, with no radiological evidence of pathosis, and minimal caries in an area that, if removed, would result in a pulpal exposure.
- Procedure – caries removal, leaving affected dentin that would risk exposing the pulp if it was removed. Calcium hydroxide or MTA layer and/or base cement, followed by the restoration of the tooth.
Older operating procedures suggested waiting 6-8 weeks. If the tooth responded well to vitality testing and was symptom free, the restoration was removed and any compromised carious tooth structure left previously was removed. Current evidence suggests this second operative step is not necessary. Evidence indicates indirect pulp capping procedures on primary teeth have a low long term success rate. Because of this indirect pulp capping is not universally advised.
Direct pulp capping is no longer common practice on deciduous teeth. A pulpotomy procedure or routine root canal therapy are more predictable treatment options.
- Indications – very small non-carious pulpal exposure in a symptom free tooth with no periapical pathology.
- Procedure – calcium hydroxide layer or MTA, with or without base, restore.
A pulpotomy is a popular pediatric pulpal procedure, where the compromised coronal pulpal tissue is removed but the relatively unaffected radicular tissue is left in place.
- Indications – a vital primary tooth subjected to a carious or accidental pulpal exposure with no visible periapical or furcal pathology, internal resorption, or history of spontaneous pain. The tooth must be restorable (obviously), and should not be close to exfoliation. If the pulpal bleeding cannot be brought under control with direct pressure in a reasonable amount of time, this may indicate unfavorable pulpal inflammation. A pulpectomy or extraction may be more appropriate.
- Procedure – local anesthesia and rubber dam, caries removal followed by the removal of the roof of the pulp chamber. The coronal pulpal tissue is extirpated with a clean No. 4 round bur, using slow speed and light pressure (to avoid further pulpal damage to radicular pulp). Clean (preferably sterile) cotton pellets are used to arrest pulpal hemorrhage. Here recommendations diverge. In the past the standard operating procedure was a 5 minute application formocresol. Other medicaments proposed include glutaraldehyde, ferric sulfate, or most recently MTA. If bleeding stops, the pulp is covered and the tooth is restored with a stainless steel crown.
A pulpectomy is complete removal of pulp from the crown and roots.
- Indications – necrotic, chronically inflamed, or infected pulpal tissue. The canals must be accessible and the tooth restorable with normal supporting bone. It is not indicated when internal or external resorption is present. If there is significant loss of bone, say from periapical pathology, the success rates decrease sufficiently to warrant extraction.
- Procedure – removal of caries, the roof of the pulp chamber, and all pulpal tissue. Care is taken when removing the radicular pulp due to the risk of damaging the developing adult tooth. The normal root canal procedure is followed and the canals are filled with something that can resorb (CaOH, Zinc-oxide eugenol) to allow normal exfoliation.
Apexification is a method of inducing a calcified barrier at the apex of a nonvital tooth with incomplete root formation. The tooth is prepared and a calcium hydroxide medicament is placed to stimulate apical closure.
Apexogenesis refers to a vital pulp therapy procedure performed to encourage the physiological development of the apical portion of the tooth root. If an adult tooth has not completed root formation (memorize the development times) this treatment will be the aim. Apexogenesis requires a functional Hertwig’s epithelial root sheath. This collar of combined inner and outer enamel epithelium of the enamel organ continues to grow down, shapes the root, and induces dentin formation.
Rubber dam is still considered the gold standard for many procedures. It can aid in child management by acting as a separation barrier and allows for better visualization, improved moisture control, decreased operative time, and airway protection. Rubber dam encourages breathing through the nose during nitrous oxide use. It only works if a clamp can be retained by the tooth, and should not be used if the patient has trouble breathing through their nose. A rubber dam cannot be used if there are fixed orthodontic appliances in the way.
FLUORIDE
Fluoride inhibits plaque formation, is bactericidal in high concentrations, enhances remineralization, inhibits glycolysis in acidogenic bacteria (by inhibiting enzymatic production of glucosyltransferase), and decreases enamel solubility by incorporating fluoride in the hydroxyapatite crystal structure (swapped out for the OH group). The greatest concentration of fluoride is on the outermost layer of enamel, and may be removed with abrasive polishing.
The target fluoride concentration in fluoridated water supplies is 1ppm, with 0.7-1.2 found in fluoridated water supplies. In warmer climates where you expect evaporative water loss the target is lowered to 0.7ppm. 3ppm would cause fluorosis in a 6 or 7 year old but not toxicity, however 8ppm would likely result in severe fluorosis and toxicity. Only ingested fluoride can cause fluorosis (not topical). If there is high enough concentration of systemic fluoride during tooth development it can cause mottling, discoloration and pitting of the enamel layer. The extent depends on the concentration of fluoride present during tooth development. Fluoride can accumulate in the skeleton.
Proximal and smooth enamel surfaces benefit the most from fluoride by turning hydroxyapatite into fluorohydroxyapatite, which is more resistant to demineralization (lower solubility). Toothpaste can be classified as low fluoride (500 ppm, kid’s toothpaste), standard fluoride (1100-1500 ppm) and high fluoride (>1500 ppm). A single strip of toothpaste covering the length of a child’s brush contains between 0.75 to 1.5 mg of fluoride. It is recommended that kids use at least 1000ppm toothpaste, supervised.
Intake that exceeds 20mg/day can inhibit the phosphatase enzyme which is important in calcium metabolism. A dose of ~0.05mg F/day/Kg is an acceptable range in terms of adequate caries control and the avoidance of unsightly dental fluorosis. The probable toxic dose for fluoride is 5mg/kg. For a 2 year old child weighing around 12kg this means 60mg of 1100ppm fluoride toothpaste, or 40% of a tube of toothpaste. For an 18kg 5 year old, 90mg or 63% of the tube. For a 28kg 9 year old, that’s 140mg or 98% of the tube.
Fluoride Toxicity
Symptoms of fluoride toxicity include nausea, vomiting, abdominal pain, increased saliva, and diarrhea. Toxicity can lead to acute cardiac failure and respiratory paralysis. Treatment includes calcium-binding products (milk/milk of magnesia) which will lower the acidity of the stomach to decrease absorption. Gastric lavage is recommended instead of an emetic agent because of the danger of aspiration. The gastric contents can cause significant burns to the esophagus due to the low pH of the hydrofluoric acid present in the stomach.
Systemic Fluoride Supplementation
Home water filtration units largely remove fluoride in the drinking water. If the natural fluoride level is greater than 0.6ppm or the child is younger than 6 months or older than 16 years, no supplemental fluoride is required.
