Morphological and Histological Properties of Primary Teeth PDF

MORPHOLOGICAL AND HISTOLOGICAL PROPERTIES OF PRIMARY TEETH Department of Pediatric Dentistry Asst. Prof. Mısra ÖZALP  THE ROLE OF PRİMARY TEETH 1-Aesthetics 2-Phonation: Necessary to produce (F, V, S, Z, T) sounds 3-Function: Chewing 4-Guidance of erup...

MORPHOLOGICAL AND HISTOLOGICAL PROPERTIES OF PRIMARY TEETH Department of Pediatric Dentistry Asst. Prof. Mısra ÖZALP  THE ROLE OF PRİMARY TEETH 1-Aesthetics 2-Phonation: Necessary to produce (F, V, S, Z, T) sounds 3-Function: Chewing 4-Guidance of eruption MORPHOLOGICAL PROPERTIES  Maxillary Central Incisor The most prominent feature is that the mesio-distal dimension of the crown is greater than the inciso-cervical dimension. Labial surface is convex and flat Its mesial corner is right angle and its distal face is more rounded. The cingulum on the palatal face is very prominent. Since the crown enamel makes a certain protrusion that separates the crown and root at the level of the collar, the collar appears to be narrowed from all sides.  Maxillary Central Incisor No developmental grooves The MD dimension is longer than the gingivo- incisal dimension.  Maxillary Central Incisor The root is single and conical in shape. The apex is round The root of the primary central tooth is longer than the permanent central tooth compared to its own crown.  Maxillary Lateral Incisor Upper lateral, similar to upper central but smaller than central When viewed from the vestibular face, the distal and mesial margins are less protruding. The distal corner angle is more rounded. Lingual anatomy is less pronounced The appearance of the collar is the same as in the central tooth. Its root is shorter than the central root, but it has the same morphological features. Root-crown ratio is higher than central incisors.  Mandibular Central Incisor Both the mesial and distal corners are sharp enough to make an angle of approximately 90 degrees. Labial face is straight. The developmental groove is not seen. The lingual face has a prominent cingulum. This is similar to the upper incisors. The root is narrow and conical, almost twice the length of the crown. The apex is not blunt as in the upper incisors, but slightly pointed.  Mandibular Lateral Incisor When the maxillary central is larger than the lateral tooth; mandibular central, smaller than lateral. Its root is conical and longer than the central cutter. It shows a definite slope distally at the apex.  Maxillary Canine They are larger than the maxillary centrals. The mesio-distal diameter is significantly larger than the heightof the crown. Thus, the crown takes on a wide view as in primary centrals. The distal corner angle is more rounded. All surfaces of the crown are convex. The cingulum on the palatal face occupies half the height of the crown, is in the form of a small tubercle, with crescent-shaped grooves on both sides.  Maxillary Canine An enamel set that divides both the vestibules and the palatal surfaces from the collar to the incisal edge leads to the formation of two mesial and distal facets on both sides. The fusion of labial and palatal enamel sets at the incisor edge causes this edge to take on a pointed appearance. It has a wide and long root in diameter. The root length is almost twice the crown. The root is straight and slightly curved distally.  Mandibular Canine Its mesio-distal diameter is quite small compared to its height. Therefore, it appears rather thin compared to the maxillary canine. The labial surface is flatter. Like the upper primary canine, the vestibular and lingual surfaces of this tooth are divided into two facets by an enamel set. The upper primary canine has root properties. Its root is slightly shorter. MORPHOLOGY OF PRIMARY TEETH Maksiller Kanin Mandibular Kanin  Maxillary 1st Primary Molar When viewed from the occlusal aspect, the crown is usually similar to the premolar crown and is triangular in shape. It has two cusps, vestibular and palatal. These two tubercles are separated from each other by a deep fissure. As a whole, the mesial half of the crown is larger than the distal half. The mesial and distal edges of the occlusal face converge slightly in the palatal direction. Therefore, the vestibular edge of the tooth is longer than the palatal edge, slightly inclined in the distal-palatal direction. The palatal margin is distinctly convex.  Maxillary 1st Primary Molar When viewed from the vestibular face, the mesial edge of the crown appears to be higher than the distal edge. In the region of the collar, there is a projection called the “Tuberculum Molare” under the vestibulo-mesial tubercle. When viewed from the mesial aspect, the palatal half of the crown appears to be lower than the vestibular half.  Maxillary 1st Primary Molar Like the permanent maxillary molars, the first molar has three roots and three canals, one palatal and two vestibular. Root characteristics of the first primary molar can be listed as follows: 1- The base part where the roots meet the crown is very small due to the narrowness of the collar. 2- Roots diverge from each other immediately after the collar in order to prepare a place for the underlying tooth germ. 3- They are thin, long and flat. 4- The inner surfaces of the roots facing each other show grooves extending all the way up to the apex. 5- The longest root is the palatal root.  Maxillary 1st Primary Molar Like the permanent maxillary molars, the first molar has three roots and three canals, one palatal and two vestibular. Root characteristics of the first primary molar can be listed as follows: 1- The base part where the roots meet the crown is very small due to the narrowness of the collar. 2- Roots diverge from each other immediately after the collar in order to prepare a place for the underlying tooth germ. 3- They are thin, long and flat. 4- The inner surfaces of the roots facing each other show grooves extending all the way up to the apex. 5- The longest root is the palatal root.  Mandibular 1st Primary Molar The crown of this tooth is different from other primary and permanent tooth crowns. When viewed from the occlusal aspect, the mesial half of the crown is larger than the distal half, with four cusps, two vestibule and two lingual. Seen from the vestibular side, this face is rhombic. In other words, the mesial and distal edges do not approach each other towards the collet, as in other primary teeth, but are parallel. The distal edge is more curved. When viewed mesially, a marked convexity is seen in the cervical 1/3 of the crown.  Mandibular 1st Primary Molar It has two roots, mesial and distal. Like the mandibular permanent molars, they are elongated and flattened. It is particularly long and flat in a particular form in the mesial. There is a deep groove on the inner surface of the roots towards the apex. The germ of the lower first premolar is located between these roots, which are separated from the collar. It has three channels, two distally and one mesially.  Mandibular 2nd Primary Molar It is a miniature of the mandibular 1st permanent molar, with a definite protrusion only on the vestibular face. The occlusal face has five cusps, three vestibular and two lingual. It is seen in square form when viewed from the occlusal perspective. The mesio-distal length of the crown is roughly twice its height. It has two roots, similar to the mandibular 1st permanent molar and having the same morphological characteristics. Between the two roots is the second premolar germ. It has three channels, two distally and one mesially.  PRİMARY TOOTH ENAMEL Structure of Enamel Permenant Teeth Primary Teeth % 95-96 inorganic % 92-93 inorganic % 2 organic % 4 organic % 2 water % 3-4 water PRİMARY TOOTH ENAMEL Structure of Enamel The inclinations of the enamel prisms are different in primary and permanent teeth. Enamel prisms in the cervical 2/3 of the crown in primary teeth and in the occlusal 2/3 of the permanent teeth lie perpendicular to the axis of the tooth. There is an aprismatic layer on the outermost surface of the tooth. Since there is no interprismatic region from this layer, it is more mineralized. This layer is thicker in primary teeth. PRİMARY TOOTH ENAMEL Structure of Enamel The organic structure of enamel consists of protein complexes, free amino acids and lipid. Enamel matures with age. As the enamel ages, the water content decreases and the crystals thicken. PRİMARY TOOTH ENAMEL Distribution of prenatal enamel in primary teeth: Most of the primary incisor enamel Half of primary canine enamel Occlusal surface of 1st molar Tubercule top of the 2nd molar tubercle are PRENATAL ENAMEL DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH  DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH General Features 1. Primary teeth are bluish white, permanent teeth are yellowish white. 2. Generally, primary teeth are smaller than permanent teeth. 3. Primary incisors and canines are more rounded than permenant incisors and canines. The vestibule faces are more convex. 4. Vestibular surfaces and interfaces of primary molars are more convex than permanent teeth. This protrusion in the vestibule is called Tuberculum molare. 5. The enamel of primary teeth shows a significant narrowing towards the collet. 6. In the occluso-cervical direction, the crown of primary teeth is shorter than the permanent teeth. The mesio-distal diameter of the deciduous crown is greater than its cervico-occlusal height. 7. The vestibule and lingual surfaces of the molar crowns converge occlusally. Therefore, the occlusal surface of primary molars is narrow compared to permanent teeth. 8. Fissures on primary teeth are less and shallow. DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH GENERAL FEATURES: 1- Primary teeth are bluish white, permanent teeth are yellowish white.  DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH GENERAL FEATURES: 2- Generally, primary teeth are smaller than permanent teeth. DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH GENERAL FEATURES: However, the amount of the M-D diameters of the primary canines and molars is greater than the M-D diameters of the permanent canines and premolars that replace them. This difference is 3.4 mm in the lower jaw; 1.8 mm in the upper jaw. DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH GENERAL FEATURES: 3- Primary incisors and canines are more rounded than permenant incisors and canines. The vestibule faces are more convex. Primary Central Incısor Primary Canine Permenant Incisors and Canine DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH GENERAL FEATURES: 4- Vestibular surfaces and interfaces of primary molars are more convex than permanent teeth. This protrusion in the vestibule is called Tuberculum molare. Upper primary 1st molar 1st Primary Molar vestibule face from mesial aspect DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH GENERAL FEATURES: Tuberculum molar causes difficulties in applying matrix or making crowns to primary teeth. DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH GENERAL FEATURES: 5- The enamel of primary teeth shows a significant narrowing towards the collet. Primary Teeth Permenant Teeth  DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH GENERAL FEATURES: 6- In the occluso-cervical direction, the crown of primary teeth is shorter than the permanent teeth. The mesio-distal diameter of the deciduous crown is greater than its cervico-occlusal height. DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH GENERAL FEATURES: 8- Fissures on primary teeth are less and shallow. DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES IN THE PULP: The crown pulp of the first molar is larger than the crown pulp of the second molar.  DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES IN PULPA: The pulp chambers of the mandibular deciduous teeth are larger than the pulp chambers of the maxillary deciduous teeth.  DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES IN PULPA: The mesial pulp horn of primary IV is closer to the surface. Lower IV is 1.6 mm., mesial pulp horn of upper IV is close to occlusal 1.8 mm Care must be taken in cavity preparation. DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES IN PULPA: The root canal of a mature deciduous tooth is wider in its dimensions than the root canal of a mature permanent tooth. DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES IN PULPA: The height of the pulp chambers is different in primary and permanent molars. While the height of the pulp chamber decreases from the first molar to the second in primary molars, the height increases from the first molar to the third in permanent teeth.  DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES IN PULPA: In contrast to the lateral canals, which are frequently encountered in the apical region of permanent teeth, there are pulp-periodontal canals opening into the periodontal space in the interroot region at the pulpal bases of primary molars. It is seen at a rate of 10-13%. Importance: In the primary teeth, the infection easily opens to the furcation area. The fistula is apical in permanent teeth and coronal in primary teeth. Primary Tooth Permanant Tooth  DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES BY ROOT: 1- While the roots of primary incisors are in the same plane with their crowns, the roots of continuous incisors are inclined towards the oral side.  DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES BY ROOT: 2- Roots of primary molars are split due to the presence of premolars underneath Primary Molar Permanent Molar  DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES BY ROOT: 3- The root of primary incisors is narrower and straighter mesio-distally than the root of permanent incisors. 4- The roots of primary molars appear longer than the roots of permanent teeth when the crown size is compared. DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES BY APPROXİMAL AREAS: 1- Primary teeth show more wear than permanent teeth. Cause: Primary tooth enamel is thinner at the interface than permanent tooth enamel → more fragile Primary Tooth Permanent Teeth  DIFFERENCES BY APPROXİMAL AREAS: 2- The septum between primary teeth is wider than the septum between permanent teeth. Permanent Tooth Primary Tooth  DIFFERENCES BETWEEN PRIMARY and PERMANENT TEETH DIFFERENCES BY APPROXİMAL AREAS: 3- The contact points of the primary teeth turn into the contact surface in a short time. Because the wear of the interfaces, chewing pressure and the pressure of the teeth to each other are effective. In deciduous teeth, the pressure exerted by the developing teeth on the deciduous teeth, the increase in luxation as a result of physiological root resorption, and the more friction of the primary teeth against each other and the easier wear of these teeth than the permanent teeth play a role. THANK YOU