Pulp morphology

The peculiarities of endodontics of deciduous teeth and immature permanent teeth. Endodontic instruments and techniques.

Actuality: the lection is devoted to endodontic treatment of children's teeth. It is important because deciduous teeth and immature permanent teeth have some differences from mature permanent teeth, so certain feature of endodontic technique must be noted. Only qualitative endodontic treatment in children may prevent early extraction of the teeth and provide their valuable function for a long time.

Object of the lecture – to present the knowledges about the features of endodontics of deciduous teeth and immature permanent teeth.

Plan of lecture:

1. Morphology of permanent and deciduous teeth.

2. Equipment for endodontic treatment.

3. Stages of endodontic treatment.

4. Endodontic technique.

5. Endodontic treatment of deciduous teeth.

6. Endodontic treatment of immature permanent teeth.

Endodontology is the division of dental science that deals with the etiology, diagnosis, prevention, and treatment of diseases of the dental pulp and their sequels. Endodontics is the branch of dental practice that applies the knowledge of endodontology (Mosby’s dental dictionary).

Two aspects are necessary to learn for introduction to endodontic treatment. They are: pulp morphology and equipment for endodontic treatment.

The pulp cavity consists of a pulp chamber in the crown from which canal(s) pass down into the root(s). As a general rule, the pulp cavities follow the contours of the teeth. Each canal opens by a foramen or foramina at the apex of the root.

Maxillary first incisor. Viewed from the labial aspect, the pulp chamber follows the general outline of the crown and is usually widest towards the incisal ridge. In a young tooth the pulp chamber has three pulp horns, which correspond to the mammelons; viewed distally, the pulp tapers towards the incisal ridge edge and widens cervically. Following a constriction, the (usually) single and centrally placed root canal tapers towards the apical foramen where it occasionally bends distally or labially. In cross-section the root canal tends to be roughly circular but tapers palatally. With age, the dimensions of the pulp cavity diminish as secondary dentine is laid down. The tip of the pulp chamber recedes until it may come to lie almost at the cervical level, and the root canal narrows especially in the mesiodistal plane.

Maxillary second incisor. The pulp cavity of this tooth is similar to, but smaller than that of the maxillarv central incisor.

Mandibular first incisor. The pulp chamber is similar to that described for the upper central incisor, being broadest incisally with three pulp horns, although the pulp horns are less well developed. The pulp chamber is oval in cross-section, being wider labiolingually than mesiodistally, and is constricted at the cervical margin. Viewed distally, the root canal in the young only narrows in the middle third of the root. The root canal is oval in cross-section, being compressed mesiodistally. With age, the pulp cavity becomes considerably constricted and ultimately its roof lies at the level of the cervical margin. However, the root canal remains rather wide in its labiolingual dimension except near the apex of the tooth.

Mandibular second incisor. This differs little from the mandibular central incisor although being slightly longer. However, the root canal often divides in the middle third of the root to give a labial and lingual branch.

Maxillary canine. The pulp chamber is wide with one pulp horn. The root canal is oval in cross-section, being wider buccopalataliy. As with the mandibular incisors, it may divide into two branches towards the apex of the tooth

Mandibular canine. The pulp chamber is narrow with one pulp horn. Both the pulp chamber and the single root canal are wider labiopalatally than they are in the mesiodistal plane. The root canal does not constrict markedly until the apical third of the root is reached. The root canal is oval or triangular in cross-section except in its apical third, where it is circular. About 20 % of single rooted mandibular canines have two root canals.

Maxillary first premolar. Whether the tooth has one or two roots, it has two root canals leaving a single pulp chamber. If the tooth is single-rooted the two root canals may merge to form a common apical foramen. The pulp chamber is wide buccopalatally with two distinct pulp horns pointing towards the cusps. From the buccal view, the pulp chamber is much narrower. The floor of the pulp chamber is rounded with the highest point in the centre. It usually lies within the root just apical to the cervix. Where the root canals arise from the pulp chamber the orifices are funnel-shaped. The root canals are usually straight and taper evenly from their origin to the apical foramina. In cross-section the root canals are generally round. With age the general shape of the pulp cavity remains the same but its dimensions, particularly the height of the pulp chamber are reduced.

Maxillary second premolar. The second premolar has a single root with a single root canal and its pulp chamber extends apically well below the cervical margin. Variations are frequent. Sometimes root canal branches in its apical third to form two apical foramina. Frequently (40%) the tooth has two root canals which join to form a common apical foramen. The appearance of the pulp cavity viewed from the buccal aspect is similar to that in the adjacent first premolar. In cross-section the root canal is oval.

Mandibular first premolar. The pulp chamber in this tooth, like the maxillary premolars, is wider buccolingually than it is mesiodistally. Unlike the pulp chamber of the maxillary premolars, there is usually only one pulp horn which extends into the buccal cusp. Occasionally a small pulp horn may pass to the lingual cusp. There is a single root canal which becomes constricted towards the middle third of the root. The canal may temporarily branch in the middle third to form two separate root canals, which rejoin near the apical foramen. In cross-section the root canal is round.

Mandibular second premolar. This differs little from that described for the mandibular first premolar. However, the pulp chamber of this tooth usually has two well-developed pulp horns projecting towards its cusps.

Maxillary first molar. The pulp chamber is quadrilateral in shape, being wider buccopalatally than mesiodistally. From the roof arise four pulp horns, one to each of the major cusps. The pulp horn to the mesiobuccal cusp is the longest. The floor of the pulp chamber generally lies below the cervical margin. From floor arise three root canals, their orifices being funnel-shaped. The root canal of the mesiobuccal root leaves the pulp chamber in a mesial direction. In cross-section it appears as a narrow slit, being wider buccopalatally. Its anatomy may be complicated by irregular branching or bifurcation near the apical foramen. The palatal root canal is the widest and longest of the three root canals.

Maxillary second molar. The pulp cavity of the upper second molar may be regarded essentially as a smaller replica of that of the neighbouring first molar. The differences are due to the more convergent roots of the second molar.

Mandibular first molar. The pulp chamber is wider mesiodistally than it is buccolingually. It is also wider mesially than distally. There are five pulp horns projecting to the cusps, the lingual pulp horns being longer and more pointed. The floor of the pulp chamber lies at, or just below, the level of the cervical margin. The root canals leave the pulp chamber through funnel-shaped orifices, of which the mesial are finer than the distal. The mesial root has two root canals, mesiobuccal and mesiolingual. Generally, the mesiobuccal root canal follows a tortuous path. The mesiolingual canal is straighter. Both are circular in cross-section. The distal root generally has a single root canal. This is considerably larger and more oval in cross-section than the mesial root canals. It generally follows a straight course.

Mandibular second molar. This closely resembles that of the adjacent first molar, though there are only four pulp horns.

The size of the pulp decreases significantly with age. When the tooth first erupts into the cavity the apical foramen is wide. The apical foramen narrows subsequent development of the root.

The morphology of the pulp cavities of deciduous teeth is extremy variable, especially once root resorption has begun. The pulp cavitie deciduous teeth are proportionately larger than those of permanent teeth and pulp horns may extend some way into the cusps.

Дата добавления: 2014-01-05