Development of Occlusion Lecture Notes PDF

Development of Occlusion By Dr. Alaa Abdelsalam Alkasaby orthodontic affect dental face correction teeth  Lecture outlines 1. What is occlusion? 2. Stages of development of occlusion 3. Predental/Gum Pads Stage. 4. Primary dentition stage  What is o...

Development of Occlusion By Dr. Alaa Abdelsalam Alkasaby orthodontic affect dental face correction teeth  Lecture outlines 1. What is occlusion? 2. Stages of development of occlusion 3. Predental/Gum Pads Stage. 4. Primary dentition stage  What is occlusion? The word occlusion means ‘closing up’ It literally means the way in which maxilla and mandible occlude. Stages of development of occlusion 1.Predental or gum pads stage 2.Primary dentition stage. 3.Mixed dentition stage. 4.Permanent dentition stage. Predental/Gum Pads Stage: (mouth of the neonate /0 to 6 months): What is gum pads Shape of gum pads Relationship between upper and lower gum pads Natal and neonatal teeth  Gum pads WHAT Alveolar arches at the time of birth Shape Smooth and firm  Transverse grooves separate the gum pads into 10 segments 11 A Lateral sulcus The groove between the canine and the first molar region  Gingival groove  Separates gum pad from the palate Lingual extension of the gum pads  Dental groove Starts at the incisive papilla extends backward to touch the gingival groove in the canine region  Relationship Between Upper and Lower Gum Pads 1. Complete overjet Maxillary gum pad is wider and overlapping mandibular one 2. The lower lateral sulcus is usually distal to the upper lateral sulcus (class ll patern)  3. Anterior open bite (infantile open bite)  Tongue protrudes anteriorly through this space help in suckling.  It is a self-correcting anomaly by eruption of primary teeth.  Natal and neonatal teeth: What is the difference??  Natal teeth are present at birth.  Neonatal teeth erupt during the first month.  Some of these teeth are prematurely erupted primary teeth. ND'D  A radiographical evaluation is recommended.  They should not be removed if normal.  Removed if supernumerary or mobile. Primary Dentition Duration of the stage Sequence and time of eruption Normal signs of primary dentition  Primary Dentition  starts from the eruption of the first deciduous tooth (usually the deciduous mandibular central incisors) PrimaryDentition Primary Dentition  ends with the eruption of the first permanent molar.  From 6 months to 6 years of postnatal life.  By 2.5 years of age, deciduous dentition is usually complete. Root formation of all deciduous teeth is complete by 3 years of age.  The normal sequence of eruption of primary teeth is as follows: 1. central incisors 2. lateral incisor 3. first molars 4. canines 5. second molars ioDF Its WIN 5gNIw Normal Signs of Primary Dentition 1. Spaced Anteriors In upper and lower anterior segments to accommodate the larger permanent teeth  2. Primate/ simian/ anthropoid space  present mesial to the maxillary canine and distal to the mandibular canine Distal of lower An This space is used for Early Mesial Shift in Mandibular Arch. 3. Almost vertical inclination of the anteriors obtuseangle interincisalangle primarydentition 8 wignsswIGjii.A 4. Over Bite  When the primary incisors erupt, the overbite is deep.  Due to vertical inclination of the primary incisors.  Over a period of time, this deep bite reduces due to two reasons:  Eruption of primary molars  Rapid attrition of incisors.  by  At about 6 years of age, there may be an edge-to-edge or zero overbite relationship.  5. Molar Relationship  Molar relationship is described in terms of the terminal planes.  Terminal planes are the distal surfaces of maxillary and mandibular second deciduous molars.  They can be related to each other in three ways: s a 1.Flush terminal plane normal  Both the maxillary and mandibular planes are at the same level anteroposteriorly  This is the normal molar relationship in the primary dentition. Jse.www.lower.ws 2. Mesial step Abnormal  Distal surface of mandibular deciduous second molar is mesial to the distal surface of maxillary deciduous second molar.  3. Distal step Abnormal  Distal surface of mandibular deciduous second molar is more distal than the distal surface of maxillary deciduous second molar.