Alginate impressions, stone models, bite registration and face-bow ... After that models and wax-up were scanned (Scanner S600 Arti, ZirkonZhan) to digital.
Comparison between conventional and CAD/CAM occlusal appliances in the management of temporomandibular disorders and/or bruxism – a randomized controlled trial. Dias R, Fonseca J, Alves C, Messias A, Guerra F Faculty of Medicine, University of Coimbra, PORTUGAL
Despite the shortage of scientific evidence, occlusal appliances remain one important tool in the multidisciplinary management of patients with bruxism and/or temporomandibular disorders (TMD). Recently, it has been suggested that CAD/CAM systems may offer advantages producing occlusal appliances and overcome some limitations attributed to conventional methods. This clinical randomized controlled trial compared the effectiveness between CAD/CAM and conventional occlusal appliances.
CLINICAL PROTOCOL
A total of 24 patients were selected in the Faculty of Medicine, University of Coimbra - Portugal. Clinical exam, RDC-TMD (Portuguese version) and Maciel questionnaire were used at baseline, 90 and 180 days. A questionnaire was developed by our research group to collect objective and subjective information from patients about appliances and therapy evolution (IMMPACT orientations). Alginate impressions, stone models, bite registration and face-bow transference were done. Models were first mounted in mechanical articulator. Over them, the technician did a manual wax-up of a mandibular stabilization oclusal appliance. After that models and wax-up were scanned (Scanner S600 Arti, ZirkonZhan) to digital articulator and designed the virtual prototype of the appliance in CAD software (Modellier, ZirkonZhan). After the definition of the final morphology, retention, thickness and occlusion scheme in virtual tool, all body of the appliance was milled in a rigid transparent acrylic using a computerized milling unit (M3, ZirkonZhan). Other appliance was obtained of the wax-up by conventional lost wax technique and at the end both were adjusted and polished manually over mechanical articulator. Each patient were constructed the two splints and at baseline both were inserted, evaluated, compared and adjusted by a experimented clinician. In this RCT protocol the randomization was made only after baseline adjustments and evaluation. According the result the patient was integrated in CAD/CAM or conventional study group. The correspondent appliance was delivered. Controls were performed at 30, 90 and 180 days.
LABORATORIAL PROTOCOL
Figure 2 – Muscle palpation during clinical evaluation. Some points Figure 1a, 1b, 1c – Clinical Case - Initial Situation checked with a – Patient with TMD after orthodontic treatment (disc calibrated device displacement with reduction, myalgia with (PALPETER) occasionally mouth opening limitation, arthralgia).
Figure 6a, 6b - Conventional and CAD/CAM appliances to same patient and ready to clinical evaluation.
Figure 4 – Intermaxilar registration at vertical and horizontal rehabilitation position desired (DELAR registration wax). Figure 3a, 3b – Face-bow transference with ARTEX device.
Figure 5a, 5b, 5c – CAD/CAM appliance in mouth (frontal and lateral views)
Figure 7 – Code Identification of each appliance in study.
Figure 8a, 8b, 8c, 8d – Intraoral occlusal evaluation of conventional appliance (MIP, protrusion, lateral excursions). 8e – Occlusal marks obtained with articulating foil (Hanel 24µm).
Figure 12a, 12b, 12c, 12d – Manual wax modeling over ARTEX articulator. Figure 14a, 14b, 14c, 14d – Check occlusion over articulator previously to clinical evaluation (Conventional and CAD/CAM appliance, respectively).
Figure 9a, 9b, 9c – Alginate impressions. Work models - stone type III.
Figure 10a, 10b – Transference of face-bow position and mounting maxillary model (articulator Artex CT).
Figure 11 – Work models mounted in mechanical articulator (ARTEX . Figure 13a, 13b, 13c, 13d – Model scan, virtual design, PMMA resin block virtual visualization and appliance after milling process.
Figure 15a – Recording thickness. 15b e 15c - Evaluation of occlusion by computerized (T-Scan) and conventional method, respectively.
SAMPLE CHARACTERIZATION AND RANDOMIZATION
BASELINE
PROGRESSION OVER TIME
Group I
Retention
Conventional vs. CAD/CAM
Mild
Positive ranks
Moderat e High
Negative ranks
46
Equal ranks
36
Conventional Yes
Adequate limits and shape
41
Yes Yes
Yes
No No
No
No
Conventional Yes
standard deviation. Compared with t-test for paired samples. 95% CI - confidence interval of 95% for the difference).
Uniform aspect and absence of distortions
Yes No
No
Yes
Correct posterior surface
Yes
Yes
No
No
Yes
Yes
Stability
Yes
Yes
No
No
No
Conventional Yes
Adjustments need to insertion
Yes
Yes
No
No
No
Anterior disocclusion guidance
Yes No
Unilateral disc
Unilateral disc displacement with reduc2on
without reduc2on
Without Classifica2on - Bilateral
Bilateral Arthralgia
Unilateral Arthralgia
Without Classifica2on
Unilateral Arthralgia
Bilateral Arthralgia
Without Classifica2on
Nor mal
Normal
Moderate
Normal
Moderate
Passivity
Yes
Yes
No
No
Mod
Severe
Mild
Moderate
Moderate
Mild
Sev
Sev
Mild
Sev
Mod
Mild
Mod
Sev
Retention R
Mild
Positive ranks
Moderate
Negative ranks
High
Equal ranks
Comfort referred by patient
Yes
Yes
No
No
Surface texture
Smooth
Yes
Roughness
No
R
Adverse reaction R
Yes
Yes
No
No
Gender
2 11 2 2 11 1 1 1 11 1 1 1 1 11 11 1 1 1 11 11 11 1 1 1 1 2
CONV.
CAD
CONVen7onal CAD
CONV.
CAD
CONV.
CAD/CAM
CONV.
Difference (95% CI)
Figure 17 – General sample characterization by RDC/TMD axis I and II classification, bruxism grade, gender and randomization result (respective study group).
Anterior Posterior Right Posterior left
Yes
No
No
CAD/CAM – incapacity rate
No
Grinding/Clench During night
Yes
Conventional – incapacity rate
No
No Smooth
Graphic 2 - Pain intensity and incapacity rate for both groups.
Roughness
Figure 12a, 12b, 12c – Clinical Case II - CAD/CAM appliance in position (frontal and lateral views). Table 7 - Evolution of the signs and symptoms reported by the Tinnitus
Yes No
Yes No
CAD/CAM– Total
patient according to the axis I –RDC-TMD (p value given by Friedman test for overall comparison of paired samples).
Conventional - Total CAD/CAM–Posterior left area Conventional– Posterior left area CAD/CAM– Anterior area Conventional– Anterior area CAD/CAM– Posterior right area Conventional– Posterior right area
No
No
Depression
GLOBAL COMPARISON RESULTS
Table 4 - Comparison of time needed to occlusal adjustments between appliances (Values in millimeters. Mean ± standard deviation.
Specific Ques+onnaire
difference).
Subjec'vely parameters related to appliance wear
No
Morphology and adapta'on aspects
Occlusal adjustments
Specific symptoms
RDC/TMD
Compared with t-test for paired samples. 95% CI - confidence interval of 95% for the
Axis I Muscule and/or ar'cular pain places
Ar'cular sounds
Specific symptoms without pain
Axis II
Mandibular range of mo'on
Signs and symptoms refered
Pain and disability
Depression
Table 2 - Comparison between objective and subjective parameters evaluated during intraoral insertion (Conventional vs CAD based on the Wilcoxon test for paired samples. positive Ranks mean higher retention for conventional gutters, negative ranks mean higher retention for leaks CAD and draws mean equal retention).
Graphic 3 - Number of occlusal adjustments necessary to equilibrate the appliances over time.
Bruxism Scale Soma'za'on
Table 8 - Evolution of the parameters evaluated by the axis II of the RDC-TMD over 180 days for both study groups (Mean ± standard deviation. ANOVA for repeated measures to evaluate the progress of each group over time (F test)). Occlusal contact classification
Anterior
Posterior
TOTAL
SS
No
Figure 16 - CAD/CAM appliance before and after occlusal adjustments, respectively.
CS WCS
Appliance contribution
Yes No
Mean
Mean
Difference
Role of appliance in clinical evolution Worst
WSS
x
x
√
CAD
R
Yes
Yes
Time needed to adjustments
Conv.
Facility to insert and remove
Conventional– intensity of pain
No
Yes
Morning facial soreness
Occlusal appliance
Yes
Grinding/Clench During day
Uncomfortable Bite position
Conventional Yes
CAD/CAM – intensity of pain
Crepitation Joint Sound
No
Conventional Yes
Graphic 1 - Comparative aspect of the variation of open/close range of motion over time for both study groups.
Conventional
Conventional Yes
Total
Click Joint Sound
Conventional Yes
CAD/CAM – opening without pain
Yes
Conventional
Conventional vs. CAD/CAM
Left
Mod
No
No
No
Conventional – opening without pain
between groups by ANOVA repeated measures with a fixed factor).
positive Ranks mean higher retention for conventional appliances, negative ranks mean higher retention for leaks CAD and draws mean equal retention).
A r e a
Right
Conventional
Table 3 - Extra oral comparison of morphologic and adaptation parameters (Conventional vs CAD based on the Wilcoxon test for paired samples.
Conventional
Articular pain sites
CAD/CAM – passive opening
Conventional
Table 6 - Characterization of painful muscle and joint locations in different periods of evaluation by appliances (Longitudinal comparison and
Normal
Mod
Conventional – passive opening
Total
Bilateral Arthralgia
CAD/CAM – active opening
Left
displacement
Conventional Yes
Muscular pain sites
No
Conventional
Conventional
Conventional Yes
Bilateral disc displacement with reduc2on
Without Classifica2on - Bilateral
Group II
Group III
No
Conventional – active opening
Right
Bruxism Scale
Table 1 – Thickness evaluation (Values in millimeters. Mean ±
Without Classifica2on
Myofascial pain
Depression
Conventional
Maciel
Difference (95% CI)
Axis II
Conventional
RDC/TD Axis I
Surface
Diagnos7c
AREA
√
x
√
x
√
x
√
x
√ √
x
√
x
x
√
x
X
√
Table 9 - Frequency of occlusal contacts in convention appliances. Occlusal contact classification
√
x
x
Table 5 – Global comparison results (SS – Statistical significance; WSS – Without statistical significance; CS – Clinical significance; WCS – Without clinical significance).
This comparative study showed similar effectiveness between CAD/CAM and conventional appliances. However, CAD/CAM presented some advantages and better clinical outcome for the patients. CAD/CAM is a potentially useful method to produce occlusal appliances.
Clinical Evolution Perspective
Anterior
Posterior
TOTAL
x
Similar Better Significant better Asymptomatic
Appliance wear in future
Always Sometimes Acute pain situation Never
Table 11 - Results of the questionnaire given to the patients to 180d control. Evaluating subjective parameters reported by the patient and prospects face to treatment (Mean ± SD scales for pain and Table 10 - Frequency of occlusal contacts in CAD/CAM appliances.
comparing CAD / CAM vs. Conventional with Student's t test. 95% CI confidence interval of 95% for the difference between means. adhesion test to chi-square for nominal or ordinal responses).
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