Pulp therapy for deciduous teeth aims to preserve the childs health and to maintain deciduous teeth where pulp tissue is affected by caries, dental trauma, or other causes in a functional state until they are replaced by permanent teeth.
It is important to maintain the primary teeth in oral cavity until its normal time of exfoliation. The main functions a primary teeth performs within the oral cavity include mastication of food and therefore helps in proper nutrition, help in speech, promote an esthetics appearance, maintain the arch length and maintain a healthy oral environment free of pain. These functions as a whole contribute to the general health and well being of the child. Therefore a clinician needs to know the art of restoring and preserving the primary teeth in the oral cavity. [1]
Small children are usually unable to verbalize the feeling of pain as effectively as adults .However, Pain caused by caries in them can manifest itself in different ways: children may eat less, sleep less, and/or exhibit negative behavior. Yet some children do not appear to complain verbally at all. Treatment of these carious lesions alleviating pain has resulted in improvement in sleep pattern and appetite. [2]
1.1 CAUSES FOR EARLY INVOLVEMENT OF PULP IN PRIMARY TEETH
Pulp chamber anatomy in primary teeth varies from permanent teeth in a number of ways which can be enumerated as:
Enamel:
The enamel of Primary teeth is half in thickness as compared to that of permanent teeth. The most superficial layer of enamel in primary teeth is also prismless which is less calcified. [3] In a study where in-vitro formation of caries like lesion was tested, the primary teeth were found to be more prone to caries due to greater mean prism-junction density and mean volume fraction of interprismatic enamel, ie due to greater porosity. [4]
Dentin:
The basic dentinal structure of permanent and primary teeth is similar but there is considerable difference in the hardness of dentin in primary teeth as compared to permanent teeth. Peripheral and circumpulpal areas have similar hardness in both the cases but the dentin immediately adjacent to pulp is considerably softer in primary dentition than in permanent dentition.Therefore differentiation of carious and soft dentin is almost impossible on the basis of touch or mechanical manipulation alone. This phenomenon has important implication in establishing protocol of management of deep carious lesions. 3
Pulp chamber:
Pulp chamber anatomy in primary teeth approximates the surface shape of the crown more closely than in permanent teeth. The pulps of primary teeth are proportionately larger and the pulp horns extend closer to the outer surfaces of the cusps than in permanent teeth.
The pulp-protecting dentin thickness between the pulp chamber and the dentinoenamel junction is less than in permanent teeth. These three factors increase the potential for pulp exposure from mechanical preparation, dental caries, and trauma. [5]
Fox and Heeley [6] concluded that, histologically, no structural differences exist between primary pulp tissue and young permanent pulp tissue with the exception of the presence of a cap-like zone of reticular and collagenous fibers in the primary coronal pulp. However, many clinicians have noted different pulp responses between primary and young permanent teeth to trauma, bacterial invasion, irritation, and medication. Anatomic differences may contribute to these responses. Primary roots have an enlarged apical foramen, in contrast to the foramen of permanent roots, which is constricted. The resultant reduced blood supply in mature permanent teeth favors a calcific response and healing by "calcific scarring." This hypothesis is exemplified in older pulps, in which more calcified nodules and ground substance are found than in young pulps. Primary teeth, with their abundant blood supply, demonstrate a more typical inflammatory response than that seen in mature permanent teeth
Some clinicians believe that primary teeth are less sensitive to pain than permanent teeth, probably because of differences in the number and/or distribution of neural elements.When comparing primary and permanent teeth, Bernick [7] found differences in the final distribution of pulp nerve fibers. In permanent teeth, these fibers terminate mainly among the odontoblasts and even beyond the predentin. In primary teeth, pulp nerve fibers pass to the odontoblastic area, where they terminate as free nerve endings. Walton postulated that if primary teeth were not so short-lived in the oral cavity, their nerve endings might terminate among the odontoblasts and in the predentin as in permanent teeth [8]
Hibbard and Ireland [9] said that the difference between the root canals of primary and permanent teeth is the existence of multiple tortuous lateral and accessory canals. Moss [10] stated that there is connection between the coronal pulpal floor and the interradicular area. Ringelstein and Seow [11] found a prevalence of 42.7% of primary molars and that this connection allows necrotic products to pass into interradicular areas. Histologic characteristic include an abundant blood supply in primary teeth. Which demonstrates a more typical inflammatory response than that seen in adult permanent teeth. Mcdonald [12] stated that localization of infection and inflammation is poor in the primary pulp than in permanent pulp.
An increased number of accessory canals and foramina, as well as porosity in pulpal floors of primary teeth, has been noted in comparison with permanent teeth.5
Finn has stated that the inflammation response to the effects of dentin caries in the deciduous pulp is more rapid than in the permanent pulp.
While comparing the anatomy between primary and permanent molars it is noticed that Primary teeth are smaller in all dimensions; their enamel cap is thinner, with less tooth structure protecting the pulp. In relation to protective enamel and dentin there is usually more pulp in primary teeth. The coronal pulp chamber of the primary teeth have three to five pulp horns that are more sharp than the outer surface.
The roots of primary molars are longer and more slender, are "pinched in" at the cervical part of the tooth, and flare more toward the apex to accommodate permanent tooth buds. All of these factors tend to increase the incidence of pulp involvement from caries or complicate canal preparation and obturation [13]
1.2 VARIOUS TREATMENT OPTIONS FOR NON-VITAL PRIMARY TEETH AND RATIONALE FOR PULPECTOMY
Because of the pulp cellular content, increased inflammatory response, and increased incidence of internal resorption, some pediatric dentists feel that the direct capping procedure is contraindicated in primary teeth. Owing to the high failure rate, pulp capping is not recommended for carious exposures in primary teeth. Other than mechanical exposure in a healthy tooth, all pulp exposures in primary teeth should be treated with pulpotomy, pulpectomy, or extraction.3
In primary teeth, the formocresol pulpotomy is a well documented and accepted procedure with a success rate of over 90%. However, in order to achieve this success rate, the treatment must be confined to teeth which are judged clinically to have inflammation only in the coronal pulp.
Dental caries involving coronal pulp extending up to root canals or trauma to teeth resulting in inflammation or hyperemia of coronal and radicular pulp usually cannot be retained in the tooth and requires extirpation of the pulp followed by filling the root canals with a suitable material that is resorbable along with the root.12 Thus making Pulpectomy one of the most undertaken procedures in Pediatric Endodontics.
Pulpectomy has been explained as: The pulpectomy procedure is a nonvital technique and involves the complete extirpation of the irreversibly inflamed and/or necrotic pulp followed by canal obturation with a resorbable medicament in primary teeth. 5
It is not always possible to perform pulpotomy in primary molars and therefore Pulpectomy is more commonly indicated due to early involvement of coronal as well as radicular pulp.
Pulpotomy also has a wide range of contraindications such as spontaneous pain, uncontrollable hemorrhage, pain on percussion and periapical or furcal pathology. Thus, primary teeth with any of the above symptoms are indicated for Pulpectomy. [14]
Pulpectomy is considered a more complicated procedure due to inherent physiologic root resorption, root canal morphology in primary teeth more so in primary molars and close proximity of the root canals with permanent successor.5,9,12
The procedure is indicated in tooth diagnosed as having irreversible pulpitis on basis of reported symptoms and /or clinical findings (e.g. profuse hemorrhage following pulpotomy procedure) or in Non-vital radicular pulp with/without associated infection. Good patient compliance is considered a major factor while selecting Pulpectomy as a treatment of choice. [15]
Extraction is another treatment of choice in case of irreversibly involved coronal and radicular pulp. However it is not preferred because maintaining the primary teeth in oral cavity, especially primary molars is of critical importance for :13
1) Aid in mastication,
(2) they serve a pulpally involved primary tooth in the absence of a succedaneous tooth,
(3) prevent aberrant tongue habits,
(4) prevent possible speech problems,
(5) Maintain esthetics,
(6) Prevent the psychological effects associated with early tooth loss, and
(7) Maintain normal eruption time of the succedaneous teeth.
Premature loss of the primary tooth may lead to accelerated or delayed eruption of the succedaneous tooth depending upon development of the permanent tooth
Fanning [16] reported in study that accelerated emergence of premolars was accompanied with early extraction of primary molar when the premolar had a well formed root whereas in some cases a delayed eruption as compared to contralateral tooth was seen when the crown was not completely formed. In latter cases initially a brief spurt in emergence was seen until the tooth leveled which was followed by a delayed eruption as the tooth remained stationary until the root completion commenced.
In some cases a delayed eruption of premolars was seen which could be attributed to scar formation. In few female patients impacted premolars was accounted because of comparatively excessive growth of jaws which led to early eruption of permanent canine.
Loss of deciduous mandibular second molar was seen to result in impacted second premolar due to mesial drifting of first permanent molar.
In cases of severe alveolar abscess accompanied with bone loss, Migration of premolars was also noticed.
Flaitz and co-workers [17] in a contrasting study compared 57 pulpotomies versus 87 pulpectomies in primary anterior teeth followed for a mean of 37 months.Based on the final radiographs in the study, treatment was successful in 68.5% of the pulpotomized group of anterior teeth versus 84% of the pulpectomized group. They concluded overall that pulpectomy was a better treatment option for primary incisors even though they may have shown more radiographic pathosis at the time of the diagnosis.
1.3 RATIONALE FOR ROOT CANAL THERAPY IN PRIMARY MOLARS
According to the American Academy of Pediatric Dentistry (AAPD) recommendations, endodontic treatment is indicated in primary teeth in which, following coronal pulp amputation, the radicular pulp exhibits hyperemia, or evidence of necrosis of the radicular pulp, with or without carious involve [18] . Despite this long standing recommendation, a 2005 survey revealed that only 85% of diplomates of the AAPD reported that they performed pulpectomy therapy. A comparable percentage of American dental school directors reported the teaching of pulpectomy therapy to their undergraduate students. [19]
Reluctance to carry out root canal treatment in primary molars may be based on the lack of consistent evidence based treatment protocol and medicaments as well as the difficulty associated with cleaning and shaping the complex root canals of primary molars. [20] Accordingly, preparation of the root canals in primary molars, unlike permanent teeth, is based on the use of chemical agents rather than mechanical debridement and by the use of an antimicrobial root canal filling material. [21]
Extraction and space maintenance was postulated to be a more predictable treatment option for some clinicians [22] , [23] , [24] , [25] particularly in the case of an uncooperative child. [26] This therapy offers an immediate and definitive solution to the symptoms of an irreversibly infected or necrotic primary molar, but it is not without detrimental consequences.
Subsequent space loss and complications with the eruption of the permanent successor frequently ensue. Use of space maintenance to prevent a loss in arch length, incurs additional cost, oral hygiene care, appliance maintenance and more frequent recall exams. [27] In a five year survey by Rajab and co-workers in year 2002 [28] , the reported overall success rate for both fixed and removable space maintainers, that included band and loops, lingual arches, Nance appliances, and partial dentures, was 30.7%. The advantage of root canal therapy is that it preserves masticatory function and maintains space for the succedaneous permanent tooth. It also avoids the precocious eruption of the permanent successor, as it has been suggested that premature loss of a primary tooth could, depending on its stage of development, accelerate or delay eruption of the succedaneous tooth [29] , [30] . Additional reasons for primary root canal therapy include preservation of a pulpally involved primary tooth in the absence of a succedaneous tooth, prevention of aberrant tongue habits, prevention of possible speech problems, maintenance of esthetics and prevention of possible psychological effects of premature tooth loss. 18
1.4 DEFINITION
Mathewson [31] Defined it as the complete removal of necrotic pulp from the root canals and the coronal portion of dental primary teeth in order to maintain a tooth in dental arch.
Finn13 defines pulpectomy as removal of all pulpal tissue from the coronal and radicular portions of the tooth
Dannenbberg [32] defined pulpectomy as the extirpation of the vital pulp,normal or abnormal followed by sterilization and filling of root canal.
However, owing to the torturous and complex root canals in primary dentition, complete removal of the radicular pulp and determination of the anatomical apex is usually not possible and therefore 'partial pulpectomy' would be a more appropriate term.
1.5 CONSIDERATIONS PRIOR TO THE TREATMENT PLAN:
Complexity of root canal system
Restorability of tooth subsequent to treatment
Periodontal tissue health
Anatomy of mouth and specific tooth to be treated.
Systemic condition of the patient
Manageability of the patient.
ACCORDING TO UNITED KINGDON GUIDELINES, PULPECTOMY IS INDICATED IF15
Tooth is diagnosed as having irreversible pulpitis on basis of reported symptoms and /or clinical findings (e.g. profuse hemorrhage following pulpotomy procedure
Non-vital radicular pulp with/without associated infection
Good patient compliance
1.6 CRITERIA FOR SUCCESS OF TREATMENT
The root is:
Firmly attached,
Remains in function without pain or infection until the permanent successor is ready to erupt,
Undergoes physiologic resorption, and
Is free from fistulous tracts.
Radiographically, success is judged by the absence of furcation or periradicular lesions and the re-establishment of a normal periodontal ligament.
1.7 INDICATIONS AND CONTRAINDICATIONS
Frank [33] classified criteria for pulpectomy of a deciduous tooth classified them into general, clinical and radiographic features. They are as follows:
GENERAL
INDICATIONS
Patient should be in good general health without any serious disease.
Maximum co-operation of patients and parents.
CONTRAINDICATIONS
Young patients with systemic illness such as congenital or rheumatic heart disease and leukemia
Children on long term corticosteroid therapy.
CLINICAL
INDICATIONS
A root previously planned for a pulpotomy that shows either a dry pulp chamber or uncontrollable pulpal haemorrhage.
A strategically important tooth such as deciduous second molar without an adjacent erupted permanent first molar,that shows clinical and radiographic signs contraindicating a pulpotomy and an undesirability of space maintainence. Maxillary and mandibular canines are equally critical especially in stabilizing arch symmetry. Also retaining maxillay incisors is important as it may be psychologically beneficial to the child as well as to the parents of the child.
Pulpectomy s also indicated in cases where a permanent successor is absent.
Any deciduous tooth with severe pulpal necrosis, provided there are no clinical or radiographic contraindications.
Primary teeth with necrotic pulps and a minimum of root resorption and bone destruction.
Primary teeth without permanent successors.
Pulpless primary teeth in systemic diseases such as hemophilia and leukemia.
Pulpless primary teeth next to line of palatal cleft.
Pulpless primary molars holding orthodontic appliance.
Pulpless teeth when arch length is deficient.
Pulpless primary teeth when space maintainers or continued supervision are not feasible as in case of handicapped or isolated children.
CONTRAINDICATIONS
Excessive tooth mobility.
Exposed furcation ares.
Perforation in floor of pulp chamber communicating with the furcation area.
Grossly decayed teeth in which extracoronal restoration can not be placed.
RADIOGRAPHIC
INDICATIONS
Adequate bony and periodontal support .
Incipient internal root resorption in the occlusal portion of the root canal
Intraradicular, interradicular or periapical radiolucent areas, provided there are no clinical contraindications.
CONTRAINDICATIONS
External root resorption.
Internal root resorption in the apical 3rd of the root or of sufficient size in the coronal third of the root to suggest possible perforation of the root.
Cyst associated with the tooth.
ROOT CANAL MORPHOLOGY OF PRIMARY DENTITION VS PERMANENT DENTITION
Knowledge of the size, morphology and variation of the root canals of primary teeth are useful in visualizing the pulp cavity during treatment. As primary teeth exhibit morphologic differences from the permanent teeth both in size and in general external and internal design, a thorough knowledge of the root canal systems of the primary teeth aids in their successful treatment.
Very few studies on root canal morphology of the primary teeth have been done. Parameters regarding the root canal morphology that may affect the treatment outcomes are: [34] , [35] , [36]
Number of roots;
Angulation of the roots;
Number of the root canals;
Diameter of the root canals;
Length of the roots.
Difference in root canal morphology of the primary teeth and that of permanent teeth exists and considerably affects the treatment outcomes. [37]
The dentist must be familiar with the various pathways that root canals take to the apex. The pulp canal system is complex and canals may branch, divide and rejoin. Weine categorized the root canal systems in any root into four basic types [38]
Vertucci and coworkers utilizing cleared teeth which had their pulp cavities stained with hematoxalin dye found a much more complex canal system and identified eight pulp space configurations . It is now established that a root with a tapering canal and a single foramen is an exception rather then a rule and this applies to primary dentition as well. [39]
Various differences in the root canal configuration of primary and permanent teeth can be summarized as:
The roots of primary teeth are proportionately longer and more slender;
Primary root canals are more ribbon-like and have multiple pulp filaments within their more numerous accessory canals;
The roots of primary molars flare outward from the cervical part of the tooth to a greater degree than permanent teeth and continue to flare apically to accommodate the underlying succedaneous tooth follicle;
The roots of primary anterior teeth are narrower mesiodistally than permanent anterior tooth roots; and In contrast to permanent teeth, the roots of primary teeth undergo physiologic root resorption.
These factors make complete extirpation of pulp remnants almost impossible and increase the potential of root perforation during canal instrumentation. As a result, the requirements of primary root canal filling materials must encompass germicidal action, good obturation, and resorptive capability.5
Performing root canal debridement and obturation in primary teeth as compared to permanent teeth is more difficult because of a number of other factors involving anatomical differences of crown and root in primary vs permanent teeth these differences have been tabulated as: [40]
Tooth anatomic
Features
Primary teeth
Permanent teeth
Significance
Overall size
Smaller
Larger
---
Pulp chamber
Larger as compared to crown
Smaller as compared to crown
Ease of access opening
Cervical constriction
Marked constriction
less constricted in lateral
Cervical region
Perforation
Root trunk
Short with thin floor of pulp chamber
Large with thicker floor of pulp chamber
Easy furcation involvement.
Root anatomy
Thin, slender (ribbon shaped) flared
Thicker, not flared
Limitation in canal enlargement, instrument breakage, perforation
Accessory canals
Present frequently in furcation area and roots
Comparatively less in number
incomplete pulp extirpation
REQUIREMENTS OF IDEAL ROOT CANAL FILLING MATERIAL
PULPECTOMY follows the Sweets philosophy of absolutism and advocates removal of all the inflamed and infected pulp tissue from the primary teeth root canal to sprocedure of pulpectomy could be completed in single appointment or multiple appointment, the final end result is control of infection within the canals followed by obturating the canals with suitable material.
Pulpectomy is therefore an important procedure usually performed in case of infected primary root canal. It can be performed in a one stage if the pulp is irreversible inflamed or in two stages in teeth where the radicular pulp is necrotic. However in both the cases the root canals are filled with a Pulpectomy material which primarily is antimicrobial and resorbable . Therefore materials such as Gutta Percha are contraindicated in primary root canal fillings except in case where the succedaneous tooth is absent. [41]
Rifkin69 identified criteria for an ideal pulpectomy obturant that include :
(1) Resorbability
(2) Antiseptic property
(3) Non-inflammatory and nonirritating to the underlying permanent tooth germ,
(4) Radiopacity for visualization on radiographs,
(5) Ease of insertion, and
(6) Ease of removal.
