developing occlusion-clinical implications and variations
TRANSCRIPT
DEVELOPING OCCLUSION-clinical
implications and variations.
PREDENTATE PERIOD
Gum pads
Maxillary- horse shoe shaped
Mandibular
Anterior open bite Contact posteriorly
They are pink, firm and fibrous
Grooves and Sulci seen
Clinical implications or variations
NATAL TEETH AND NEONATAL TEETH
PRIMARY DENTITION: from 6 months to 6 years of age.
As a general rule, the mandibular dentition precedes the maxillary dentition, except for the
maxillary lateral incisors.
Chronology of eruption of primary teeth
Lower central incisors
Upper central incisors
Upper lateral incisors
Lower lateral incisors
First molars
Canines
Second molars
Clinical implications or variations
Clinical implications or variations
Neonatal teeth
Eruption Cyst
Characteristics of Primary Dentition
• OVERJET• OVERBITE • SPACES IN DENTITION• RELATIONSHIP OF SECOND
DECIDUOS MOLARS
Sagittal relationship in Primary Dentition
What is ‘OVERJET’?
The incisors usually are in normal overjet relation of 1mm or in an edge to edge relationship.
Sagittal relationship in Primary Dentition
Vertical relationship in Primary Dentition
What is ‘OVERBITE?
Vertical relationship in Primary Dentition
Overbite reduces throughout the primary dentition until the incisors are edge to edge, which can contribute to marked attrition.
Clinical implications or variations• Influence of habits like thumb and digit sucking may lead to : -Increased overjet -Anterior open bite
Cross bite
Spaces in primary teeth
Generalized spacing
Primate spaces
• No spacing• Crowding in
primary teeth
Clinical implications or variations
This leads to increased probability of crowding in permanent dentition as dental arch length
anterior to second primary molars does not increase after their eruption
Usually because of larger mandibular second molars, the distal surfaces of the occluding second molars are
flush, whereby the term "flush terminal plane" or straight terminal plane.
Determining the terminal plane relationships in theprimary dentition stage is of great importance as it
guides the erupting first permanent molars into occlusion
Terminal plane relationship between the distal surfaces of the maxillary and mandibular second
primarymolars.
A, Flush terminal planes. B, Mesial step with the C, Distal step with the mandibular plane mesial mandibular plane to the maxillary plane. distal to maxillary plane.
Clinical implications or variations
MIXED DENTITION: from 6 years to 12 years of age.
First transitional period
Characterised by: Eruption of Permanent First Molars Eruption of Incisors
Chronology of eruption of permanent teeth
Clinical implications or variations
Eruption of Permanent First Molars
CLASS l MOLAR RELATION
CLASS ll MOLAR RELATION
CLASS lll MOLAR RELATION
• The FIRST PERMANENT MOLARS when erupt , they utilise the spaces present in the primary teeth to drift mesially. This is called
EARLY SHIFT OF PERMANENT MOLARS
• FORWARD GROWTH OF MANDIBLE
Eruption of Permanent First Molars
Factors that change molar relationship pattern in primary molars to that in permanent molars:
The first Permanent Molars may erupt into one of the following occlusal relationships
Clinical implications or variations
The maxillary arch, on the average, has just enough space to accommodate the permanent lateral incisors when they erupt. In the mandibular arch, however, when the lateral incisors erupt, there is on the average 1.6 mm less space available for the four mandibular incisors than would be required to perfectly align them.
This difference between the amount of space needed for the incisors and the amount available for them is called the "incisor liability." ‘INCISOR LIABILITY’
Eruption of Permanent Incisors
Because of the incisor liability, anormal child will go through a transitory stage of mandibular incisor crowding at age 8 to 9 even if
there will eventuallybe enough room to accommodate all the
permanent teeth in good alignment
Where did the extra space come from to align these mildly crowded lower incisors?
Most jaw growth is in the posterior, and there is no mechanism by which the mandible can easily become longer in its anterior region.
Rather than from jaw growth per se, the extra space comes from three sources:
• Proclination of incisors• Eruption of incisors in a wider arc• Utilization of spaces of primary dentition• Increase in inter canine width
7 years old 9 years old 14 years old
Eruption of Permanent Maxillary Incisors
UGLY DUCKLING STAGE
Clinical implications or variations
UGLY DUCKLING STAGE
Clinical implications or variations
Diastema may be caused by an erupted or unerupted Supernumery tooth in midline(1) or a low frenum(2)
(1)
(2)
Clinical implications or variations
Thumb sucking and digit habits may lead to anterior openbite
Clinical implications or variations
Sometimes the deciduous incisor may be retained leading to palatalEruption of Maxillary Incisor
Clinical implications or variations
Permanent Maxillary Incisors may develop palatally Leading to CROSSBITE
Intertransitional period
This stage is characterized by continued eruption of already
erupted permanent teeth. No significant changes occur.
Second transitional periodThis period, characterized by shedding of the primary canines and molars, emergence of the permanent canines, premolars,
and permanent second molars
Leeway space;1.8mm in maxilla 3.4 mm in mandible
This leeway space is utilized by permanent molars as they drift mesially. This is called late mesial shift. So that a flush terminal relationship is converted into a class I molar relationship
Mandibular molar normally moves mesially more than its maxillary counterpart.
Clinical implications or variations
Improper utilization of LEEWAY SPACE may lead to CROWDING
WHY??
BECAUSE:
Even if incisor crowding is present, the leeway space is normally taken up by mesial movement of the permanent molars.
SOLUTION: An opportunity for orthodontic treatment is created at this time.
PERMANENT DENTITION: from 12 years of age to eruption of third
molars
The overbite often ranges between 10% and 50%, and the overjet ranges
between 1.0 and 3.0 mm.
PERMANENT DENTITION
Intercanine width : canine to canine.
- ↑ 1-2 mm during primary dentition.- ↑ 3 mm in mixed dentition. Growth is completed around 9 years.
MaxillaMandible
Development of the dental arches
Changes in Dental Arches from 6 TO 13 yrs
Clinical implications or variations
Tooth – jaw size discrepancy may lead to (1)CROWDING or(2) DENTAL PROTRUSION
(1)
(2)
TEETHING
Teething is the process by which an infant's teeth sequentially appear by breaking through the gums
TEETHING
The process of teething is sometimes referred to as "cutting teeth".
TEETHINGSIGNS:• General irritability• Disturbed sleep• Loss of appetite • Chewing of objects • Bruises/swelling in gums:Some blood and bruising during
teething is common in most infants and babies:Not all babies bleed from the mouth when teething, but in some cases, a pocket of blood in the gum just above the tooth ruptures. eruption isn't any more painful than usual. It just looks scary to parents!
• Excess salivation
• Running nose • Teething has not been shown to cause fever or diarrhea. A
slight rise of temperature may occur when the teeth come through the gum, but this does not make a baby ill.
Historical management of teething
• . Remedies that have been prescribed for teething through the ages have included blistering, bleeding, placing leeches on the gums, and applying cautery to the back of the head!
• Lancing • Systemic medicamentsOpiates and poisons such as lead acetate, mercurials and bromide. many of these compounds are actually causative of the symptoms associated with teething!
• The teething relief method under constant debate is the age-old remedy of rubbing rum or whiskey on the baby's gums.
Current methods of the management of teething
Non-pharmacological management• Teething rings • Hard, non-sweetened rusks made from flour and wheatgerm with no sugar or sweetener • Reassurance
Pharmacological management• Topical agents• Systemic analgesics
‘Alternative' holistic medicine• acupressure, • aromatherapy,• and homeopathy
DIFFERENCES BETWEEN PRIMARY AND PERMANENT
TEETH