In the past few decades, technical developments of dental implants in combination with continuous development of surgical techniques and biomaterials have led to an expansion of the indications for implant-retained prosthetics. Prevention of atrophy after tooth extraction by socket or ridge preservation or reconstruction of the alveolar crest in cases of atrophy by augmentation with autologous bone or bone substitute materials of different origins have become reliable treatment options to establish a sufficient implantation bed [1,2,3,4].

However, extensive augmentation procedures as therapy of choice for all patients should be viewed critically. Due to compromised general health, anamnestic data, or individual demands of the patient, minimally invasive methods to restore oral function should be considered. In this context, the development and scientific investigation of so-called short implants, which are implants with reduced length, play an important role, as they seem to allow placement of dental implants in the molar region of the atrophic maxilla and, at the same time, avoid the need for sinus augmentation procedures. A further indication of short implants is the molar region of the lower jaw, in which the possibility of implant placement can be restricted due to the anatomical position of the nervus alveolaris inferioris.

Although short implants have been reported in the literature for several years, the term “short implants” is used quite heterogeneously to indicate implant lengths. While in the present study short implants with a length of 7 mm are investigated, Mangano et al. considered short implants to have a length of 8 mm [5]. This guiding value has also been reported as 8.5 mm, and even 10 mm, which indicates scientific disagreement on this topic [6, 7].

Major concerns regarding technical and biological complications due to the increased crown-implant ratio in short-length implants have been expressed. In a systematic review, Blanes et al. excluded correlation between the occurrence of biological and technical complications and the crown-implant ratio of implant-supported reconstructions [8]. Especially regarding bone loss, the literature review showed that the crown-implant ratio does not influence peri-implant crestal bone loss. Similar findings are reported by Nunes et al., who reported that dental implants of 4-mm width and 7-mm length and implant-supported fixed prostheses with a crown-implant ratio larger than 2 had no positive correlation to marginal bone loss [9].