# Bonding Failures of Lingual Orthodontic Brackets:
###### Abstract  
The aim of the present study was to evaluate in a clinical setting the bracket survival of lingual brackets bonded with the KomonBase system, and to compare it to the survival of a customized lingual bracket system. Two convenience samples of 13 consecutive patients treated with lingual fixed appliances with KomonBase extensions (Group 1) and 14 consecutive patients treated with customized Inception(tm) lingual fixed appliances were retrospectively enrolled (Group 2). First time debondings were recorded from the files. Data were submitted to statistical analysis and a Log-rank test was used to compare the Kaplan-Meier survival curves between the two groups. Statistical significance was set as \(p<0.05\). Lingual brackets bonded with the KomonBase system showed a failure rate of 8%, while Inception brackets showed a failure rate of 7.1%. The Log-rank test comparing the Kaplan-Meier survival curves revealed no statistically significant difference between the two groups (\(p=0.343\)). Most debondings occurred during the first 6 months. Upper incisors and canines were less prone to debond than premolars and molars. In conclusion, no difference in bracket survival was observed between the KomonBase system and a customized lingual appliance.  
Keywords:orthodontics; fixed appliance; lingual orthodontics; debonding; KomonBase; bracket failure rate; indirect bonding +
Footnote †: journal: Medical  
chairside time and improving the precision of bracket placement: brackets are first placed on a dental cast, then transferred to the patient's mouth through a transfer ray on all teeth of the same arch simultaneously. However, there are contradicting results regarding the real accuracy in bracket positioning [3,10], and full or partial transfer trays are not indicated for cases with severely crowded teeth or when large tooth movements due to extractions, expansion or distalization are expected [11].  
The KCommonBase system [12,13] is an alternative indirect bonding system that allows custom placement of any type of lingual bracket at a custom distance from the tooth surface through a customized composite resin base. A high flow filled flowable resin is placed to fill the gap between the metal bracket base and the tooth surface, followed by the application of a high flow unfilled flowable resin to extend the resin base to completely cover the lingual tooth surface [13]. The KCommonBase system thus presents the advantage of offering a large, self-positioning bonding base that allows precise positioning of any standard lingual orthodontic bracket chosen by the practitioner, without depending on a customized bracket system. This extended bonding base allows for single tooth bonding in presence of severely crowded teeth, or for rebonding in case of debonding [11]. This system is offering several advantages, such as the possibility of using a straight wire instead of a mushroom-shaped wire, an immediate bonding of all brackets even on severely crowded teeth, and an easier rebonding procedure in case of debonding [11]. Despite these advantages, it should be evaluated whether the presence of the custom resin base affects bonding strength, given the importance of debonding rates from a clinical perspective [14, 15, 16].  
The aim of the present study was to evaluate in a clinical setting the bracket survival of lingual brackets bonded with the KCommonBase system, and compare it to the survival of a customized lingual bracket system.