Oftentimes, dentists find themselves answering a long list of questions from parents regarding the treatment of their child’s primary teeth. The one question that seems to crop up frequently is “why should we treat primary teeth if they will fall out?” The reasons for treating caries in the primary dentition are to prevent the spread of the bacteria, maintain space and prevent infections (in the form of an abscess or facial cellulitis). Furthermore, carious teeth in children may result in pain, disrupt their quality of life and affect their overall development.1 Therefore, proper management through the removal of dental caries and placing appropriate restorations is very important in children.
The type of restoration placed on primary teeth is dictated by the extent and location of the carious lesion. For instance, in cases with shallow mesial or distal caries in primary molars, a traditional class II preparation using composite resin, resin-modified glass ionomer cement or amalgam can be used.2 Studies have shown that ideal class II preparations have a lower failure rate compared to slot preparations, resulting in better longevity of the restoration.3
Restorative options become important with extensive caries. The ideal restorative material for such carious lesions in posterior primary teeth is a stainless steel crown (SSC). However, many general dentists and parents do not prefer this treatment option.6 In a survey conducted by Threlfall et al (2005), 88 percent of general dentists prefer using a glass ionomer restorations for extensively carious molars in situations where pediatric dentists would place a SSC. A study in Indiana concluded that SSCs are being significantly underutilized in the general dental practice.4
SSCs superiority over Class II restorations in large carious lesions in primary molars can be attributed to the anatomy. The narrow bucco-lingual dimensions and relatively flat interproximal contours in primary molars can cause overextension when preparing class II restorations in large carious lesions. This may produce unsupported enamel at the buccal and lingual margins, which under function, leads to open margins. This will lead to the formation of recurrent decay and failure of the restoration. If pulpal necrosis forms on the tooth then a dental abscess and/or facial cellulitis will result.6,11 SSCs have been shown to have better durability and longevity compared to other restorative materials.5 Furthermore, they have a lower risk of retreatment relative to large class II restorations, especially for the first primary molars.6 SSCs are indicated for primary teeth with multi-surface carious lesions, interproximal lesions that have undermined the marginal ridge, when cervical decalcification is present or for pulp-treated primary molars.2,5,6 They should also be considered in patients that are high-caries risk and those with developmental defects such as amelogenesis imperfecta or dentinogenesis imperfecta.5
When faced with restoring primary teeth, adequate treatment planning is of upmost importance because lack thereof may lead to failure of the restoration and eventual loss of the tooth. A retrospective study by Unkel, et al. (1997) found that 47 percent of facial cellulitis cases were of odontogenic origin in children and this was most common in the mixed dentition stage (mean age at 8.8 years). Furthermore, posterior teeth were responsible for the highest number (64.3 percent) of odontogenic cellulitis cases. In children, spread of infection is faster and the effects are more pronounced, making management of dental caries a high priority.10
Premature loss of primary teeth can lead to space loss which, in turn, can result in deviations of the midline, crowding, tooth impaction, ectopic eruption, or crossbite formation.7 Therefore, proper treatment planning is paramount and dentists need to be aware of the indications of SSCs and become more comfortable with their placement. Cases outlining the repercussions of poor treatment planning are presented below.
Case 1:
A five-year-old healthy female presented to the Hospital for Sick Children Department of Dentistry dental clinic with pain and right-sided facial cellulitis. The patient was on day two of a seven-day course of Amoxicillin. An extra-oral examination revealed a firm, erythematous swelling on the right side of the patient’s cheek extending from the inferior border of the infraorbital rim to the border of the mandible. On intra-oral examination, swelling was noted on the buccal aspect of teeth 54 and 55. Tooth number 54 was found to have grade II mobility and was sensitive to percussion. No sign of clinical caries was noted, however, a slot preparation with a composite restoration was present on the distal surface of 54. The restoration was completed approximately two weeks prior by the child’s dentist. A periapical radiograph was taken to identify the cause of the cellulitis (Fig. 1).
FIGURE 1. A periapical radiograph of the upper right posterior area is presented. Tooth 54 is shown to have a failed slot restoration with decay still present under the restoration. The periodontal ligament around the furcation area of tooth 54 is lacking a defined outline and is noticeably enlarged./201501130942230c41yvxr3hxwfav45aw4ym155.jpg)
The radiograph revealed a failed “slot-prep” restoration on 54 DO. In addition caries was still present under the restoration. Poor choice of restorative materials and inadequate restorative technique caused the restoration to fail which then resulted in infection in the form of dental abscess and facial cellulitis. The proper management for the interproximal caries on 54 would have been pulp therapy (for example, a pulpotomy procedure if the pulp was found to be vital at the time of treatment) followed by the placement of a SSC. This case vividly illustrates what can happen when a dentist is attempting to be conservative in restoring a tooth that clearly requires more comprehensive treatment. A “slot-prep” restoration does not have the strength to withstand the forces placed on a primary molar. Secondly, this case clearly shows what the repercussion is of inadequate caries removal. Treatment in this case included the removal of tooth 54 using local anaesthetic after completion of the antibiotic course and reduction of the facial cellulitis.
Case 2:
An eight-year-old healthy male presented to the emergency room (ER) department at the Hospital for Sick Children with pain on the left side of his face. The pain started five days prior and the patient was not able to sleep the night before coming into the ER. His dental history was significant for multi-surface restorations on teeth 74 and 75 by a private dentist within the last year. There were no significant findings on extra-oral examination. Although there were no soft tissue changes, intra-orally, tooth 75 was identified as the cause of the pain. Tooth 75 responded positive to pain upon percussion and had a mesio-occlusal composite resin restoration. A radiograph was taken to confirm 75 as the cause of discomfort to the patient (Fig. 2).
FIGURE 2. A periapical radiograph of the lower left area is presented. Tooth 75 has a large MO restoration with recurrent decay present under it in close proximity to the mesial pulp horn. Loss of definition and enlargement of periodontal ligament can be noted in both the furcation area a
nd along the roots of tooth 75. This large furcation radiolucency indicates the presence of pulpal necrosis and a dental abscess. Note that tooth 74 also has recurrent decay under its DO restoration./201501130942231c41yvxr3hxwfav45aw4ym155.jpg)
The periapical radiograph shows that the restoration on tooth 75 was close (if not into) the mesial pulp horn and recurrent decay was present around the margins. This combination led to irreversible pulpitis with periapical periodontitis. In preparing these teeth one must be cognizant of the anatomy of the pulp horns in primary molars and recognize when the pulp is involved. This requires very careful investigation of the preparation following caries removal looking for pulp exposures. If the pulp was involved at the time of treatment then pulp therapy would be indicated followed by the placement of a SSC. The recurrent decay present under both 74 and 75 are clear examples of the consequences of using class II restorations in treating large carious lesions on primary molars in a high-caries risk individual. SSCs are the most reliable choice in restoring these teeth. The treatment in this case involved the extraction of tooth 75 with the use of local anaesthetic and a referral back to the patient’s dentist to treat the caries on tooth 74 and to place a space maintainer.
Case 3:
A 5-year-old healthy female presented to the dental clinic at the Hospital for Sick Children Department of Dentistry with a “pimple” in the mouth on the upper right side. The patient’s dental history was significant for a restoration on tooth 54 completed by a dentist in the community. The parent noted the “pimple” one week after the restoration was placed and seemed to have increased in size over a period of one month. There was no history of pain, fever or lymphadenopathy. Extra-oral examination did not reveal any signs of infection or pathology. However, intra-orally a draining fistula was present on the attached gingiva buccal to tooth 54. Tooth 54 was found to have grade I mobility. A periapical radiograph was taken which clearly indicated the presence of an abscess on tooth 54 (Fig. 3).
FIGURE 3. Periapical radiograph of the upper right posterior area is presented. The film reveals a large 54 DO restoration with recurrent decay in close proximity to the distal pulp horn. Radiolucency around the furcation area and enlarged periodontal ligament space of 54 is apparent in the radiograph./201501130942242c41yvxr3hxwfav45aw4ym155.jpg)
Radiographically it is obvious that the restoration is in close proximity to the pulp and there is decay present along the margins of the restoration. This resulted in pulpal necrosis and the subsequent formation of an abscess. Tooth 54 would have benefitted from pulp treatment followed by the placement of a SSC. Unfortunately, tooth 54 was extracted to prevent the spread of infection.
Dicussion:
Properly restored primary teeth help to prevent the spread of infection and maintain space for the permanent dentition. Primary molars are important space maintainers and early loss of these teeth may lead to the permanent molar encroaching into the space and subsequent malocclusion.12 Hence, importance of space maintenance should be taken into consideration when treatment planning and restoring primary molars.
It is important to note that minor changes in treatment, for example using ideal class II preparations as opposed to slot preparations will lead to better results for smaller interproximal lesions. As seen by case one, slot preparations cannot withhold occlusal forces and therefore are more prone to leakage and reccurent decay. The use of stainless steel crowns is the most reliable restorative option available for primary teeth. Both cases two and three had deep class II composite restorations that led to leakage and reccurent decay. The resultant pain and infection could have been prevented by placing a SSC which would have provided full coverage, a better seal, and increased the longevity of the teeth.
These cases emphasize the importance of proper treatment planning and placing appropriate restorations in the primary dentition. In doing so, we can contribute to the quality of life of our young patients and prevent repercussions such as dental abcess, cellulitis and space loss.
Dr. Poonam Sekhon and Dr. Anuradha Mukerji are dental residents in the Department of Dentistry at the Hospital for Sick Children and Holland Bloorview Kids Rehabilitation Hospital, Toronto Ontario. Both authors contributed equally to this article.
Oral Health welcomes this original article.
References:
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3. Summitt JB, Della Bona A, Burgess JO. The strength of Class II composite resin restorations as affected by preparation design. Quintessence International 1994; 25(4):251-7
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The remaining references can be found online at www.oralhealthgroup.com.
