01 Ottobre 2019

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Importance of clinical and genetical evaluation for non-syndromic oligodontia in orthodontics

Clinical case

Antonio Gracco, Giovanni Bruno, Can Kuskhonmaz, Alberto De Stefani

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Objectives  Hypodontia is one of the most common congenital dental abnor­malities. It affects approximately between the 2 to 10% of the gen­eral population. It is frequently as­sociated with other oral anoma­lies, such as structural variations and malformations of other teeth, late eruption, transposition and crowding.

The most commonly missing permanent teeth are the third molars (9-37%), followed by mandibular second premolars (<3%), maxillary lateral incisors (<2%) and maxillary second pre­molars and mandibular incisors (<1%). More than 300 genes are involved in tooth development and the most common genes associ­ated with the hypodontia are: WN­T10A, MSX1, PAX9 and AXIN2. WNT family member 10A, LDL re­ceptor-related protein 6, and WNT family member 10B are all impli­cated in oligodontia phenotypes.

Using whole-exome, novel and known variants in WNT pathway genes can be identified, and par­ticularly in WNT10A, as pathogen­ic for familiar oligodontia. The ob­jective of this case report is to evaluate the importance of the treatment and diagnosis of oli­godontia in a healthy patient.

Materials and methods  A 14-year-old male patient at­tended for an orthodontic con­sultation. The clinical examina­tion revealed missing of four third molars, four mandibular in­cisors, two second lower premo­lars and two second lower mo­lars. Two lateral maxillary inci­sors resulted microdontic.

Fami­ly anamnesis did not reveal his­tory of dental agenesis. The pa­tient and his family were directed for a genetic consultation. Ortho­dontic treatment objectives were the alignment of the upper and lower dental arches, correction of positions of the central inci­sors and manage the space for the restorative therapy of micro­dontic teeth and future implant and prosthodontic treatment.

Results  The genetic analyses find that par­ents of the patient and the patient himself have a mutation of WN­T10A gene. As parents are carriers of the mutation there is a 50% risk that this mutation will be passed onto their son.

Therefore, the pa­tient is diagnosed with compatible oligodontia. The patient holds a risk of 100% of passing this muta­tion to his children. Patient started his treatment with bonding of up­per dental arch with a system cus­tomized vestibular brackets and a prosthetic bite to give a support to lower arch and reduce overbite.

After creating the space for micro­dontic lateral incisors, a conserva­tive treatment was made on four superior incisors for make an aes­thetics smile.

Conclusions  The patient with oligodontia gen­erally suffer abnormal occlusion, difficulty in mastication and speech among with altered facial appearance which may cause psychological distress.

A strong genetic link associated with oli­godontia helps the dentist to know the possibility of its occurrence in other family members and in fu­ture generations.

Clinical significance  It is fundamental to direct the patients affected by oligodontia to a genetic analysis and know the probability of passing the mutation to their children.

Dental rehabilitation of patients with oli­godontia requires orthodontic, prosthodontic and conservative treatment at the appropriate time jointly by a paediatric den­tist and other dental specialists to improve oral health and psy­chological development of the child.

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doi: https://doi.org/10.19256/d.cadmos.08.2019.08