PDO315 Space Maintenance
Page 2: Patient Assessment
Starting point for working with patients in need of space maintenance.
Page 3: Essential Concepts to Master
Understanding space maintenance requires knowledge of:
Permanent teeth counting (1-32)
Primary teeth counting (A-T)
Typical eruption patterns of primary teeth
Typical eruption patterns of permanent teeth
Counting teeth in mixed dentition
Page 4: Counting Permanent Teeth
Sequence for counting permanent dentition:
8, 9, 7, 10, 6, 11, 5, 12, X, 4, 13, 3, 14, 2, 15, 1, 16
32, 17, 31, 18, 30, 19, X, 29, 20, I, 28, 21, 27, 22, 26, 25, 24, 23
Page 5: Counting Primary Teeth
Sequence for counting primary dentition:
E, F, D, G, C, H, B, I, A, T, K, I, S, L, R, M, P, N
Note: Focus on crowns of D's and E's during assessments.
Page 6: Eruption Timing and Sequence of Primary Teeth
Primary tooth eruption:
Begins around 6 months; complete by 36 months (variable)
Mandibular central incisors erupt first, maxillary second molars last
Sequence in both arches: A-B-D-C-E (incisors, molars, canines)
Occlusion typically established by 36 months with little change prior to permanent dentition eruption.
Permanent teeth eruption sequence:
Maxillary: 6-1-2-4-5-3-7-8
Mandibular: 6-1-2-3-4-5-7-8
Page 7: AAPD Eruption Chart
Primary Dentition:
Central Incisors: 4th fetal month, calcified 18-24 months, erupt 6-10, exfoliate 7-8 years
Lateral incisors: same timing with different eruption completion
Canines: 4th fetal month, calcified 30-39 months, eruption at 16-20 months
Primary first molars follow a similar timeline.
Permanent Dentition:
Central and lateral incisors: calcified 3-4 months, erupt 7-10 (max) and 6-7 (man)
Canines start between 4-5 months, erupt between 11-15 years.
Page 8: Mixed Dentition Assessment
Utilizing panoramic images to group teeth effectively for easier assessment in mixed dentition.
Page 9: Primary Dentition Arch Space Concept
2/3 of primary dentition generally exhibits spacing.
Primate spaces: mesial to upper canines and distal to lower canines.
Leeway space: refers to the greater length between primary canines and molars compared to their permanent counterparts.
Measurements: Maxillary: 1mm, Mandibular: 2mm per quadrant.
Page 10: Eruption and Occlusion of Primary Dentition
Spacing characteristics in primary dentition:
Primate spaces are common regardless of spacing type (Baume I and II).
Page 11: Leeway Spaces
Leeway spaces vary in size by arch:
Maxillary: 1mm per quadrant
Mandibular: 2mm per quadrant.
Page 12: Mixed Dentition Occlusion: Molar Transition
Factors affecting transition:
Primary molar relationship
Primary spacing (early mesial shift)
Leeway space (late mesial shift)
Differential growth of maxilla and mandible.
Page 13: Early Mesial Shift
Process of closing interdental spacing before permanent molars erupt, influenced by primary molar eruption paths. Occurs around 4 years of age.
Page 14: Late Mesial Shift
Refers to the mesial shift of permanent first molars into leeway space after exfoliation of second primary molars.
Contributes to Class I molar relationship in permanent dentition, especially in the mandibular arch.
Page 15: Primary Incisors
Space loss generally unlikely if primary canines are erupted and occluded (around 20 months).
Options include pedi-partial/Hollywood bridge or partial denture for cosmetic reasons, though not commonly needed.
Page 16: General Concepts of Space Maintenance
Concerns regarding early loss of primary canines include preventing arch collapse and maintaining midline symmetry.
Options include:
Lingual arch with spur
Extraction and bilateral space maintainer.
Page 17: Primary Molars
Space maintenance typically unnecessary if permanent premolar cusp tips are at the pulp chamber level.
Page 18: Primary First Molars
Space maintenance is usually required if the first molar is lost before the permanent one erupts.
Band & Loop is the most common space maintainer used for these cases.
Page 19: Primary First Molars (continued)
Space maintenance discussions continued with emphasis on common solutions.
Page 20: Primary Second Molars
Space maintenance is required regardless of timing regarding loss.
Distal Shoe recommended if the first permanent molar is not yet erupted.
Page 21: Primary Second Molars (continued)
Further exploration of space maintenance techniques.
Page 22: Ectopic Eruption of Permanent First Molars
Up to 3% of the population may experience this condition.
Monitor for self-correction; can require intervention if no progress observed.
Treatment options:
Distalization of first molar
Extraction of primary molar with traditional space maintainer.
Page 23: Ectopic Eruption (continued)
Further detailing the implications and interventions needed for ectopic eruptions.
Page 24: Appliances for Ectopic Eruption
Common appliances:
Halterman Appliance
Brass ligature wire
Arkansas spring
Orthodontic separating elastics.
Page 25: Unilateral Space Maintenance Concepts
Utilization of applicable codes for restoring missing teeth, methods include:
Traditional (lab fabricated)
Chairside methods.
Advantages & disadvantages discussed.
Page 26: Chairside Preparation for Unilateral Space Maintenance
Step-by-step guide for creating a unilateral space maintainer chairside versus in a laboratory.
Page 27: Bilateral Space Maintenance Concepts
Ideal when permanent first molars are in occlusion.
Advantages include maintaining arch perimeter and success dependent on oral hygiene.
Page 28: Bilateral Space Maintenance Appliances
Common types:
Transpalatal Arch
Nance Arch
Lower Lingual Holding Arch (LLHA).
Page 29: Bilateral Space Maintenance: Preparation
Detailed process for fabricating bilateral space maintenance appliances, including securing bands and adding components.
Page 30: Important Concepts for Space Maintenance
Recap of vital aspects:
Overview of unilateral versus bilateral options.
Importance of hygiene and monitoring.
Passive nature of appliances; no orthodontic forces exerted.
Page 31: Conclusion
Final remarks summary overview relaying critical takeaways.