This document discusses study model construction and trimming for orthodontic diagnosis. It describes making impressions, casts, and bases for maxillary and mandibular study models. Proper trimming involves using templates, squares, and guides to ensure models are symmetrical and meet standardized measurements for anatomical and artistic portions. Well-trimmed models accurately reproduce teeth and soft tissues for evaluating malocclusions and treatment planning.

1. STUDY MODELBASING AND
TRIMMING
PRESENTED BY
SUSNA SARAH PAUL
DEPT. OF ORTHODONTICS

2. CONTENTS
●
INTRODUCTION
●
STUDY MODELS
●
BASING
●
TRIMMING OF MAXILLARY CAST
●
TRIMMING OF MANDIBULAR CAST
●
CONCLUSION

3. ●
Orthodontic diagnosis deals with recognition of
the various characteristics of the malocclusion.
Diagnostic aids fall into two categories
-Essential Diagnostic Records
-Supplemental Diagnostic Records

4. ESSENTIAL DIAGNOSTIC
AIDS
SUPPLEMENTAL
DIAGNOSTIC AIDS
●
1)CASE HISTORY.
●
1)SPECIALIZED RADIOGRAPHS
●
2)CLINICAL EXAMINATION.
●
2)ELECTROMYOGRAPHY.
●
3)STUDY MODELS.
●
3)HAND-WRIST RADIOGRAPHS.
●
4)RADIOGRAPHS
●
4)ENDOCRINE TESTS.
●
5)FACIAL PHOTOGRAPHS.
●
5)BMR ESTIMATION.
●
6)OCCLUSOGRAMS.

5. ●
According to Proffit, these records fall
into three categories:
I. Teeth and oral structures
II.Evaluation of facial proportion
III.Occlusal evaluation

6. STUDY MODELS
●
Orthodontic study models are
essential diagnostic records,
which are accurate plaster
reproductions of the teeth
and their supporting soft
tissues and which help to
study the occlusion and
dentition from all the three
dimensions.

7. Purpose of Making Study Models
1) Valuable in planning treatment as threedimensional records of patients dentition.
2) Occlusion can be visualized from all
aspects.
3) Provide a permanent record at the start of
therapy..
4)nature and severity of the malocclusion.
5)explain the treatment plan and progress..
6)transfer records.

8. Steps in construction of study
models.
1.Impression making.
2.Taking a wax bite.
3.Disinfection of the impression.
4.Casting the impression.
5.Basing and trimming.
6.Finishing and polishing.
7.Care of the study models.

10. BASING

11. RUBBER MOULD BASE
FORMERS

15. TRIMMING OF MODELS

17. Template or degree plate

18. Squaring tool and angle guide (Tsquare)

19. TRIMMING OF MAXILLA

28. TRIMMING OF MANDIBLE

35. 13
mm
ANATOMICAL
PORTION
ARTISTIC
PORTION
3:1

36. 60mm
70mm
55mm

37. CONCLUSION
Models accurately reproduce the teeth and their
surrounding soft tissues.
Models are to be trimmed so that they are
symmetrical and pleasing to the eye.
Models are to be trimmed so that they meet the
measurements and angles as proposed for trimming
them.
Models are to have a clean, smooth, bubble free
surfaces with sharp angles where the cuts meet.