Comparison of implant component fractures in external and internal type: A 12-year retrospective study

Abstract

PURPOSEThe aim of this study was to compare the fracture of implant component behavior of external and internal type of implants to suggest directions for successful implant treatment.MATERIALS AND METHODSData were collected from the clinical records of all patients who received WARANTEC implants at Seoul National University Dental Hospital from February 2002 to January 2014 for 12 years. Total number of implants was 1,289 and an average of 3.2 implants was installed per patient. Information about abutment connection type, implant locations, platform sizes was collected with presence of implant component fractures and their managements. SPSS statistics software (version 24.0, IBM) was used for the statistical analysis.RESULTSOverall fracture was significantly more frequent in internal type. The most frequently fractured component was abutment in internal type implants, and screw fracture occurred most frequently in external type. Analyzing by fractured components, screw fracture was the most frequent in the maxillary anterior region and the most abutment fracture occurred in the maxillary posterior region and screw fractures occurred more frequently in NP (narrow platform) and abutment fractures occurred more frequently in RP (regular platform).CONCLUSIONIn external type, screw fracture occurred most frequently, especially in the maxillary anterior region, and in internal type, abutment fracture occurred frequently in the posterior region. placement of an external type implant rather than an internal type is recommended for the posterior region where abutment fractures frequently occur.

Risk factors for abutment and implant fracture after loading

“…This study only assessed patients receiving Ankylos implants because most of the implants used during the study period were of this brand. This eliminated any fracture rate differences possibly attributable to differences in implant morphology and abutment-implant connection methods [6]. The Ankylos implant body is made of pure titanium grade 2, easier to process than grade 4 and reported to show higher shear contact strength when in contact with bone [24].…”

“…Fracture of the veneering material; loosening or fracture of the abutment screw; and fracture of the framework, abutment, or implant are the worst-case scenarios and have been reported following long-term prosthesis use [4,5]. The fracture rate of implant components, including the implant, abutments, and abutment screws, is 5.6% [6]. Bruxism and the crown-implant ratio (C/I) are possible causes of internal stress that lead to mechanical complications [7].…”

“…Previous studies [1][2][3][4][5][6][7][8][9][10] have examined the risk factors for fracture of the implant component; the incidence of implant and abutment fractures is reportedly low. Possible causes are multifactorial, such as dental implant manufacturing and design failure, bruxism or large occlusal force, superstructure design, implant positioning, implant diameter, metal fatigue, and bone resorption around the implant.…”

Screw loosening and changes in removal torque relative to abutment screw length in a dental implant with external abutment connection after oblique cyclic loading

“…Removing the screw remnant from the implant after a fracture is both challenging and time consuming 353637. A 12-year retrospective study showed that screw fractures occurred most frequently among components in external connection implants, and the fractured screws were not retrieved in 6.2% of cases 38. From the clinical point of view, when screw fracture occurs, it is important to remove the fractured remnant.…”

Fractures of implant fixtures: a retrospective clinical study

“…The number of cases was insufficient to obtain statistically significant results, and few existing studies have supported this finding. However, the reason why screw fracture occurs more frequently in the external connection type and abutment fracture or fixture fracture more frequently in the internal connection type was explained by Yi et al [26] in 2018. When a force is applied to an implant, the internal connection type and the external connection type show structurally different force distributions.…”