The Mechanism of Second Dentition in Humans
MECHANISM OF
SECOND DENTITION
Diphyodont and Heterodont humans
homodont: all tooth are alike;
heterodont: teeth have diferent shapes;
poliphyodont: changing of teeth for the whole lifetime
diphyodont : 2 sets of teeth – mammals;
MOORREES CF
,
FANNING EA
,
HUNT EE Jr
.
AGE VARIATION OF FORMATION STAGES FOR TEN PERMANENT TEETH.
J Dent Res.
1963 Nov-Dec; 42:1490-1502.
Root development -
Root development -
MOORREES et al.
MOORREES et al.
SECON DENTITION -
MECHANISM
Mechanism – several factors responsible for normal second
dentition process
•
Primary teeth period, after development of primary teeth
–
transitory period: maxillary bones are preparing for the
permanent teeth arrival.
SECOND DENTITION
Physiological developmental phenomenon
;
Dynamic process: root development, p
e
r
i
odontal
development, func
t
ional occlusion.
Normal develpment of the craniofacial complex;
Treatment planing, timing - orthodontics;
Cariology.
SECOND DENTITION -
IMPORTANCE
6 years: M
1
First permanent molars: at the end of the line
;
•
„Sechsjahrmolaren”;
•
There are no changing of teeth, so it goes often
unnoticed by the parents!
ERUPTION - TIMETABLE
CHARACTERISTICE
Percentil presence of permanent teeth:
prevalence of a
particular tooth at a given moment in the population.
dierences between the arches;
sexual dimorfizm;
Dental age determination!;
dental status or the given age.
CHARACTERISTICS
Average eruption time:
the age when the percentil presence
of the tooth is 50%.
IMPORTANCE:
describes the second dentition process;
comparative studies between populations;
acceleratio
: comparison with older data!;
Percenti presence: tooth type 15-40%
Average eruotion time: tooth
type 1-1,5 years.
BONE MATURATION
Second dentition is paralell with bone maturation:
•
Tanner-Whitehouse method TW2 (Tanner et al. 1975);
Orthodontic diagnostic value!
GROWTH- TANNER
Chronological age
SECOND DENTITION CRITERIA
Presence of the permanent toothgerm
Optimal position of the toothgerm
Sufficient space
Physiological root resorption
PRESENCE OF THE PERMANENT
TOOTH GERM
Aplasia prevalence: 3-4%;
Gábris et al.: I
2
˃pm
2
˃ PM
2
˃i
1
Persisting primary teeth
Bolk’s terminal reduction theory
15
APLASIA: 35; 31; 41; 45.
Persisting primary teeth: 75; 71; 72; 85
Persisting primary teeth: 75; 71; 72; 85
Bolk’s terminal reduction theory: EXEPTION
Bolk’s terminal reduction theory: EXEPTION
LOWER PERMANENT FIRST INCISORS
LOWER PERMANENT FIRST INCISORS
OPTIMAL POSITION OF THE
PERMANENT TOOTHGERM
Lower incidors: lingual eruption, erupting often in the
presence o the primary incisors;
Extraction of the primary teeth;
Upper canines:
Ectopia;
Retentio/Impactio
17
•
DENS SUPERNUMERARIUS
DENS SUPERNUMERARIUS
•
DENS SUPPLEMENTARIUS
DENS SUPPLEMENTARIUS
MESIODENS
Early primary teeth
extraction
Physiological root resorption
Genetical code!
PATHOLOGY
TIME
TIME
SPACE
SPACE
THE PATHOLOGICAL TRIAS:
THE PATHOLOGICAL TRIAS:
Perturbance of the rootresoption;
Perturbance of the rootresoption;
Persisting primary models;
Persisting primary models;
Retained permanent teeth.
Retained permanent teeth.
PATHOLOGY
DENTITIO PRAECOX
DENTITIO PRAECOX
DENTITIO TARDA
DENTITIO TARDA
DENTITIO DIFFICILIS
DENTITIO DIFFICILIS
INFRAOCCLUSIO SECUNDARIA
Partialis retentio; reinclusio;
Submergentia;
„Halbretention”
„submerged deciduous teeth”
Eruption cyst/haematoma
Importance of the distal plane in primary
dentition
Second dentition is a natural process involving the development of a second set of teeth in humans. This complex phenomenon includes factors like root development, periodontal changes, and functional occlusion. The process is crucial for normal craniofacial development and has implications for orthodontic treatment and cariology. The eruption timetable for permanent teeth is also highlighted, emphasizing the importance of recognizing and monitoring the stages of dental development.
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Presentation Transcript
MECHANISM OF SECOND DENTITION
Diphyodont and Heterodont humans homodont: all tooth are alike; heterodont: teeth have diferent shapes; poliphyodont: changing of teeth for the whole lifetime diphyodont : 2 sets of teeth mammals;
Root development - MOORREES et al. Root completely develped Apex open Apex closed Apex closed root root root MOORREES CF, FANNING EA, HUNT EE Jr. AGE VARIATION OF FORMATION STAGES FOR TEN PERMANENT TEETH. J Dent Res. 1963 Nov-Dec; 42:1490-1502.
SECON DENTITION - MECHANISM Mechanism several factors responsible for normal second dentition process Primary teeth period, after development of primary teeth transitory period: maxillary bones are preparing for the permanent teeth arrival.
SECOND DENTITION Physiological developmental phenomenon; Dynamic process: root development, periodontal development, functional occlusion.
SECOND DENTITION - IMPORTANCE Normal develpment of the craniofacial complex; Treatment planing, timing - orthodontics; Cariology.
6 years: M1 First permanent molars: at the end of the line; Sechsjahrmolaren ; There are no changing of teeth, so it goes often unnoticed by the parents!
ERUPTION - TIMETABLE Eruption sequences 4 5 3 3 4 5 vagy 4 3 5 PERMANENT T. Hidasi Feh r Upper 1. Molars 6 6-7 1. incisos 8 6-8 Eruption sequences Lower Lateral incisor 8 7-9 , 3 4 5 Canine 11 9-12 1. and 2. Praemolars 9-10 10-12 2. Molar 12 11-13 3. Molar - 17-21
CHARACTERISTICE Percentil presence of permanent teeth: prevalence of a particular tooth at a given moment in the population. dierences between the arches; sexual dimorfizm; Dental age determination!; dental status or the given age.
CHARACTERISTICS Average eruption time: the age when the percentil presence of the tooth is 50%. IMPORTANCE: describes the second dentition process; comparative studies between populations; acceleratio: comparison with older data!; Percenti presence: tooth type 15-40% Average eruotion time: tooth type 1-1,5 years.
BONE MATURATION Second dentition is paralell with bone maturation: Tanner-Whitehouse method TW2 (Tanner et al. 1975); Orthodontic diagnostic value!
GROWTH- TANNER End of secondary dentition Chronological age
SECOND DENTITION CRITERIA Presence of the permanent toothgerm Optimal position of the toothgerm Sufficient space Physiological root resorption
PRESENCE OF THE PERMANENT TOOTH GERM Aplasia prevalence: 3-4%; G bris et al.: I2 pm2 PM2 i1 Persisting primary teeth Bolk s terminal reduction theory
APLASIA: 35; 31; 41; 45. Persisting primary teeth: 75; 71; 72; 85 Bolk s terminal reduction theory: EXEPTION LOWER PERMANENT FIRST INCISORS 15
OPTIMAL POSITION OF THE PERMANENT TOOTHGERM Lower incidors: lingual eruption, erupting often in the presence o the primary incisors; Extraction of the primary teeth; Upper canines: Ectopia; Retentio/Impactio
MESIODENS DENS SUPERNUMERARIUS DENS SUPPLEMENTARIUS 17
Physiological root resorption Genetical code!
PATHOLOGY TIME SPACE THE PATHOLOGICAL TRIAS: Perturbance of the rootresoption; Persisting primary models; Retained permanent teeth.
PATHOLOGY DENTITIO PRAECOX DENTITIO TARDA DENTITIO DIFFICILIS
INFRAOCCLUSIO SECUNDARIA Partialis retentio; reinclusio; Submergentia; Halbretention submerged deciduous teeth
