A Literature Review to Assess the Correlation between Implant Insertion Torque, Bone Density and Implant Failure
: The Implications for Loading Protocols.

  • Neil Schembri

Student thesis: Master's ThesisMaster of Science (MSc)


Aims & Objectives: To assess whether any correlations can be identified between
the implant’s insertional torque (IT), bone density and failure and to assess the
implications of these findings in relation to the loading schemes available.

Materials & Methods: An electronic data search for (implant* and torque).tw,
limited to humans and dentistry journals, was inputted into Medline on OvidSP
followed by a comparative search in Pubmed. In this review, 61 articles were
included representing 168 failed implants.

Results: 44% (n=74) of the 168 failed implants were immediately occlusally
loaded, 84.7% (n=61) of this group were inserted with an IT >30Ncm.
25.6% (n=43) of the 168 failed implants were not loaded and 62.8% (n=27) of this group were inserted with an IT of <30Ncm.
22.6% (n=38) of the 168 failed implants were immediately non-occlusally loaded
and 81.6% (n=31) of this group were inserted with an IT of <35Ncm.
4.2% (n=7) of the 168 failed implants were conventionally loaded while the
remaining 3.6% (n=6) were early occlusally loaded.
The most under-represented data was the bone density description.

Conclusions: a high degree of primary implant stability in the form of a high value of implant IT appears to be one of the prerequisites for implant success as this limits implant micro movements (Makary et al., 2011, Heschl et al., 2012, Margossian et al., 2012). A low IT increases the risk for failure (Ottoni et al., 2005), however, implant failure is a multi-factorial process. Avoiding direct occlusion during the healing phase appears to increase the likelihood of a favourable outcome (Aparicio et al., 2003, Calandriello et al., 2003, Pieri et al., 2012, Grandi et al., 2012b). There is no agreement in the literature on a threshold IT value below which no implant should be immediately or early loaded. Placing implants into medium/high density bone allows the achievement of a higher primary stability, however, when placing implants into low density bone, the osteotomy procedure should be modified to facilitate the achievement of a higher IT and thus a higher primary stability (Gonzalez-Martin et al., 2012, Pieri et al., 2012). The proposed implant prognosis table could act as a visual aid providing inexperienced clinicians the ability to decide on the implant’s loading protocol thus helping to prevent implant failure.
Date of Award10 Nov 2014
Original languageEnglish
Awarding Institution
  • University of Bristol
SponsorsMalta Government Scholarship Scheme
SupervisorDominic J O'Sullivan (Supervisor)

Cite this