Osseointegration refers to the phenomenon for close apposition of the bone to the surface of an implant with no interposing tissue that can be clinically demonstrated by absence of mobility [1, 2]. Obtaining primary stability seems to be a precondition for a successful osseointegration [3]. Dental implants have a success rate of over 90% and are available in various sizes with different surfaces [4, 5]. The diameter of dental implants usually ranges from 3 mm (narrow diameter) to 7 mm (wide diameter), with the majority falling in the “standard diameter” range of 3.7 to 4.0 mm.

Single-piece mini dental implants (MDIs) or narrow diameter implants (NDIs) are being widely used for stabilizing complete dentures [6], orthodontic anchorage [7, 8], single-tooth replacements, and fixing surgical guides for definitive implant placement, and as transitional implants for support of interim removable prosthesis during the healing phase of final fixtures [9–11].

Due to the MDIs’ narrower diameter (1.8–2.4 mm) as compared with regular implants, the width of the bone required for their placement is smaller, making the surgery minimally invasive as compared with the surgery for conventional implant insertion [12]. In addition, transmucosal placement is performed using a single pilot drill, reducing the need for sutures and long recovery periods [13]. Mini dental implants can also be immediately loaded and are cost-effective, which makes them an advantageous alternative for mandibular implant overdentures [13, 14]. The success of these implants will depend, however, on their capacity to outstand functional loadings.

Osseointegrated implants are clinically characterized by the absence of mobility, which can be assessed by measuring the primary and secondary implant stability [15, 16]. Some authors have suggested that primary stability is a critical factor in predicting whether an implant will be successful or not, and it is considered of highest importance in the long-term success of dental implants [17, 18]. It has also been reported that micro movements can be detected at an early stage by measuring the primary implant stability and that they are unfavorable to the osseointegration of dental implants [19–21].