Dr. Simona Tecco
• Graduated with honours and academic distinction in Dentistry and Dental Prosthetics in Chieti in 1999; PhD in Odontostomatological Sciences at the University of Chieti; PhD in Physiology of Mastication and Dental Materials at the University of Turin; Specialisation in Orthodontics at the Università Cattolica del Sacro Cuore (Rome)
• From 2000 to 2011 she attended the Department of Odontostomatological Sciences at the University of Chieti as an internal doctor, dedicating herself to clinical and research activities
• From 2014 to 2017 she was University Researcher at the University Vita-Salute San Raffaele, Milan
• Since 2017 she is Associate Professor at the at the University Vita-Salute San Raffaele (Milan) and Consultant at the San Raffaele Hospital, Dentistry Unit.
Dr Alessandro Nota, Dr Laura Pittari, Dr Francesco Manfredi Monticciolo, Dr Pauline Bazzucchi
introduction
Temporomandibular disorders (TMDs) are a group of diseases that affect both the temporomandibular joint (TMJ) and the masticatory muscles, as well as associated structures such as periauricular areas 1 which are the main cause of nonodontogenic facial pain12. A 1993 study by Lipton et al. found that TMJ pain was reported by 5.5% of the population in a survey of 45,711 American families3. In addition, previous studies indicate that approximately 75% of patients have at least one sign of joint dysfunction (abnormal jaw movement, joint noises, painful palpation, etc.) and approximately 33% have at least one TMD symptom (facial pain, articular pain etc)4. Chronic pain causes related psychological and wellbeing issues which in its complexity lowers the overall patients quality of life5, which is the main reason why patients seek healthcare6. It is well documented that the factors influencing TMJ degeneration can be divided into intra-articular variables (mainly joint disc position and specific joint components) and general factors (gender, age, and tooth loss)4 . This documentation presents a broad consensus on the direct correlation between the increase in age and abnormal disc position (internal disorder), both of which have been found to significantly influence TMJ degeneration.
“TMDs are a group of diseases that affect both the temporomandibular joint and the masticatory muscles, as well as associated structures such as periauricular areas.”
In these types of cases, a repositioning splint is commonly used for the management of disc displacement in order to re-establish a normal condyle-disc relationship, eliminating any joint pain and noises through recapturing the disc7. By doing so, a smooth, coordinated, and painless range of motion can be achieved.
Many studies have been conducted to understand whether orthodontic treatments may or may not cause TMD. Some articles turns over this concept, using the orthodontic treatment as a treatment indicated in subjects with TMDs8-12. Thus after the use of the occlusal splint previously mentioned, a subsequent orthodontic treatment can be added to the treatment plan in order to maintain the new condylar position by adjusting the interocclusal relationship. To perform a complex treatment plan like this, a precise preliminary planning of the treatment stages in required, from the initial TMD management to the final orthodontic finalization. This planning helps to minimize errors and increase the predictability of the overall outcome, enabling an interdisciplinary management approach of the case13-16 . This specific case report describes the digital planning of a combined treatment with an occlusal splint followed by an orthodontic finalization to achieve mandibular repositioning and occlusal stability in a young adult female affected by TMD.
the case
The patient was referred to the dentistry department at San Raffaele’s Hospital in Milan, Italy, due to orofacial pain specifically related to the right temporomandibular joint. The patient reported the onset of symptoms in 2012, including episodes of mandibular locking, followed by the development of lateral deviation and increased joint pain. The patient has been diagnosed as a bruxist, reporting previous orthodontic treatment with a fixed multi-brackets appliance followed by TMD therapy with splints in 2019. Extra-oral examination showed neither skeletal nor soft tissue deviation. Clinical intraoral examination evidenced a thin gingival phenotype with localized recessions in the lower incisors in addition to erosion and abrasion on all the teeth surfaces except on canines. An intra-oral examination showed a right molar and canine class II and on the left side a molar class I and canine class II. An overjet of 3 mm and an overbite 4 mm were measured. The upper and lower midlines were both shifted to the right compared to the facial midline, with the upper deviating 2mm and the lower 3 mm (Fig. 1).
The examination of the TMJs revealed the presence of joint clicks on both right and left sides. During the maximum mouth opening a deflection to the left was detected but with no opening limitation. Palpation of the masticatory muscles indicated pain in the right and left external pterygoid muscles. Electromyographic examination showed an increased activation of masseter and temporalis muscle on the right-side. (Fig. 2).
The examination of the cervical range of motion, assessed using an accelerometer (Baiobit©, BTS s.p.a., Garbagnate Milanese, MI, Italy), revealed joint limitations in both flexion and extension movements with a difference a 24° lower than the normal range for extension movement and a difference of 7° lower than the normal range for flexion (Fig. 3).
The MRI highlighted an anterior articular disc displacement and reduction in the left TMJ as well as a course of inflammation in the capsule’s posterior compartment (retrodiscitis). In the right TMJ the MRI showed thinning of the disc (Fig. 4).
Modjaw appliance (Tech in MotionTM, Villeurbanne, France) was used for the kinematics examination which revealed an altered opening pattern, with a deviation to the left side (Fig.5).
In order to plan a mandibular repositioning after the preliminary evaluation of the kinematic activity of the mandible the same device helped to identify the preferred therapeutic mandibular position.The STL files of the repositioned dental arches were shared with the technician who designed and manufactured the dental appliances (Fig.6).
For this process S.v.e.d.17 (sagittal vertical extrusion device) was chosen as the preferred appliance to be worn during the night, whereas a modified Gelb’s appliance 17 f was selected to be worn during the day (Fig.7).
Once the correct fitting of the appliance was confirmed and the proper instructions were given, the patient was monitored every 2 months. After 6 months from the beginning of treatment, the symptoms had significantly reduced and both the clinicians and the patient noticed a compelling change in the habitual occlusal relationship (fig.8).
Thus the patient proceeded with the orthodontic therapy with clear aligners aimed to finalize the therapeutic position. For this patient a comprehensive InvisalignTM package was chosen and its clincheck was planned in order to finalize the TMD therapy using the splint‘s position as a guide for the InvisalignTM planning (fig. 9).
During the first sets of aligners, the patient wore the night splint (thus, the maxillary teeth had no movement during these stages) on the upper arch and the aligner on the lower arch, whereas both aligners (with the upper aligner being passive) were worn during the day, with vertical elastics on the precision cuts, to extrude lower first molar, premolars, and canine (fig.10).
At stage 34, all the mandibular movements were completed (fig.11a), the surfaces of molars, premolars and canine were nearly occluding, and thus from aligner 35 passive aligners were positioned in the mandible whereas orthodontic movements started in the maxilla with a change in the position of both precision cuts and attachments (fig. 11b).
A new Gelb splint was prepared to be worn by the patient during the night in case of discomfort in addition to the upper aligner, without elastics (fig. 11c) until the occlusal contacts reached the optimal relationship (fig. 11d).
Stronger occlusal contacts were achieved in the first molar and premolar areas.
After the first months of treatment, the patient already doesn’t complain of pain nor TMJ noises. In fact, the orthodontic treatment aimed to create a stable occlusion and a new mandibular position for the patient that reflects the occlusal splint treatment position preventing overloads in the intra-articular space.
In this clinical case, the digital analysis of mandibular kinematics allowed the integration of diagnostic procedures and the simplification of the clinical aspects, through a preliminary evaluation. The three-dimensional design of the devices reduced the risk of complications and subsequent phases of modification of the device, since the laboratory received an STL file of the arches in the therapeutic position with the kinematic paths of the condyles instead of a construction bite.
Kinematic analysis with ModjawTM allows the identification of a therapeutic mandibular position for the devices and evaluates in real time the actual trajectories of the condyles starting from that therapeutic position.
It therefore allows a comparison of the condylar tracings that start from the habitual occlusal position, with those that start from the hypothesized position for the devices.
The digitalisation of the protocol reduces the manufacturing time for the devices, and potential errors.
The STL files in the identified position can be emailed to the lab, thus reducing the number of critical steps in the workflow.
Despite the considerable digital advantage, a preliminary, adequate, and careful clinical TMD evaluation and a correct interpretation of the signs and symptoms, especially regarding the acquisition of the anamnesis, and the palpation of muscles and TMJs, cannot be eliminated nor substituted.
“Kinematic analysis with ModjawTM allows the identification of a therapeutic mandibular position for the devices.”
The digitalisation of the workflow entails a significant upfront cost and a learning curve for the clinician. On the other hand it has many advantages: such as providing the possibility of making a diagnosis in a dynamic perspective for complex cases19; the rapid manufacturing of the occlusal splint; and finally, the possibility of memorizing the treatment position giving the clinician the possibility to review and virtually plan the design of the TMD (or prosthetic) device, before its realization, comparing it with the real kinematics of the patient.
Once the occlusal splints are confirmed to be clinically useful for the management of the patient’s signs and symptoms 20-21 , the treatment position and the mandibular kinematics will also be available to colleagues for finalization, within the interdisciplinary dental team who will have to deal with the prosthetic and/or conservative part of the finalization. Orthodontic aligners can also be a valid therapeutic instrument for the finalization in these cases, because they allow the use of a splint during therapy and a precise planning and preview of movements, with particular attention to the real predictability of the final position, which is hard to achieve with the fixed orthodontic device.
conclusion
The clinician, with aid of digital technologies, could be able to firstly identify a new mandibular and condylar position and apply it to the dental arches with occlusal splints with the aim of treating the TMD symptomatology. Then, a proper digitally planned orthodontic treatment with clear aligners could be able to achieve a stable habitual occlusion that reflects the previously identified mandibular position and condylar position.
This workflow seems to allow the patient to be free from constantly wearing invasive occlusal devices. The suggested workflow, in fact, could address TMD by utilizing the patient’s own occlusion and aligning their teeth.
A proper clinical exam and wise experience of the clinician are of crucial importance to properly approach the case, while digital technologies allow the clinician to have a more conscious and precise analysis of the patient’s condition and treatment plan.
Additional clinical studies should be performed on this topic to confirm the results of this clinical protocol.
REFERENCES
1 List T, Jensen RH. Temporomandibular disorders: Old ideas and new concepts. Cephalalgia. 2017;37(7):692-704.
2 KaposFP, ExpostoFG, OyarzoJF ,DurhamJ .Temporomandibular Disorders :a review of current concepts in aetiology, diagnosis and management. Oral Surg. 2020 (4):321-334.
3 Lipton JA, Ship JA, Larach-Robinson D. Estimated prevalence and distribution of reported orofacial pain in the United States. J Am Dent Assoc. 1993 ;124(10):115-21.
4 Buescher JJ. Temporomandibular joint disorders. Am Fam Physician. 2007 Nov 15;76(10):1477-82.
5 Dahlström L, Carlsson GE. Temporomandibular disorders and oral health-related quality of life. A systematic review. Acta Odontol Scand. 2010 Mar;68(2):80-5.
6 De Kanter RJ, Truin GJ, Burgersdijk RC, Van ‘t Hof MA, Battistuzzi PG, Kalsbeek H, Käyser AF. Prevalence in the Dutch adult population and a meta-analysis of signs and symptoms of temporomandibular disorder. J Dent Res. 1993 Nov;72(11):1509-18..
7 Albagieh H, Alomran I, Binakresh A, Alhatarisha N, Almeteb M, Khalaf Y, Alqublan A, Alqahatany M. Occlusal splints-types and effectiveness in temporomandibular disorder management. Saudi Dent J. 2023 Jan;35(1):70-79.
8 Michelotti A, Rongo R, D’Antò V, Bucci R. Occlusion, orthodontics, and temporomandibular disorders: Cutting edge of the current evidence. J World Fed Orthod. 2020 Oct;9(3S):S15-S18. .
9 Michelotti A, Iodice G. The role of orthodontics in temporomandibular disorders. J Oral Rehabil. 2010 May;37(6):411-29. doi: 10.1111/j.1365-2842.2010.02087.x. Epub 2010 Apr 9. PMID: 20406353.
10 Mohlin B, Axelsson S, Paulin G, Pietilä T, Bondemark L, Brattström V, Hansen K, Holm AK. TMD in relation to malocclusion and orthodontic treatment. Angle Orthod. 2007 May;77(3):542-8.
11 Nota A, Caruso S, Ehsani S, Ferrazzano GF, Gatto R, Tecco S. Short-Term Effect of Orthodontic Treatment with Clear Aligners on Pain and sEMG Activity of Masticatory Muscles. Medicina. 2021; 57(2):178. https://doi.org/10.3390/medicina57020178
12 Zhang S H, He K X, Lin C J, Liu, X D, Wu L, Chen J, Rausch-Fan X. Efficacy of occlusal splints in the treatment of temporomandibular disorders: A systematic review of randomized controlled trials. Acta Odontol. Scand.2020 78: 580:589.
13 Yang Y, Li J, Xia Z, Tang B, Li Y. Mesenchymal stem cells-derived exosomes alleviate temporomandibular joint disc degeneration in temporomandibular joint disorder. BiochemBiophys Res Commun. 2024 ;726:150278.
14 Tecco S, Caputi S, Teté S, Orsini G, Festa F. Intra-articular and muscle symptoms and subjective relief during TMJ internal derangement treatment with maxillary anterior repositioning splint or SVED and MORA splints: A comparison with untreated control subjects. Cranio. 2006 (2):119:29.
15 Tecco S, Nota A, Pittari L, Clerici C, Mangano F, GherloneEF. Full-Digital Workflow for TMDs Management: A Case Series. Healthcare (Basel). 2023 11(6):790.
16 Nota A , Chegodaeva A.D, Ryakhovsky A.N, Vykhodtseva, M.A, Pittari L, Tecco S. One-stage virtual plan of a complex orthodontic/prosthetic dental rehabilitation. Int. J. Environ. Res. Public Health 2022 19:1474.
17 Farha KF. Sved appliance. Cranio Clin Int. 1991;1(2):123-4.