Surface resorption following two forms of rapid maxillary expansion

Area of Science:

• Orthodontics
• Craniofacial Biology
• Dental Histology

Background:

• Posterior cross-bite of skeletal origin is often treated with rapid maxillary expansion (RME).
• Different appliances, such as tissue-borne acrylic (Haas) and all-wire framework devices, are used for RME.
• The incidence and pattern of root resorption associated with these appliances require further investigation.

Purpose of the Study:

• To compare the frequency and nature of premolar root resorption following RME using either a Haas appliance or an all-wire framework appliance.
• To examine the relationship between root resorption patterns and the duration of the retention period post-RME.

Main Methods:

• RME was performed on nine patients: five with a Haas appliance and four with an all-wire framework appliance.
• Maxillary and mandibular premolars were extracted for histological examination after the expansion phase.
• Root surfaces were analyzed to quantify and characterize resorption lacunae.

Main Results:

• Root resorption was primarily observed on the buccal surfaces of maxillary premolars in both groups.
• Premolars treated with the all-wire framework appliance exhibited more extensive root resorption compared to those treated with the Haas appliance.
• Greater root resorption was found in teeth extracted shortly after expansion, while less resorption was noted with longer retention periods.
• No significant root resorption was observed in mandibular premolars.

Conclusions:

• The tissue-borne acrylic appliance (Haas) appears preferable for RME to minimize buccal surface root resorption due to its maximum anchorage.
• Further research with longer post-treatment observation is necessary to fully understand the root surface healing process.