The ill-fitting complete denture can result in soreness and
atrophy of the jaws which is a discomfort to the patients [13]. The all-on-four concept offers
comfortable solution for patients with atrophic jaws. The immediate
implant-support restoration provides patient greater satisfaction. The outcome
is better quality of patient’s life [14]. In the study of Lopes et al.,
difficulty in doing surgery was classified based on a score- low (residual
ridge of > 5mm), moderate (irregular residual ridge of 4-5mm) and high
(irregular residual ridge of < 4mm) [15]. The under drilling of implant site
does enhance the insertion torque by preventing counter sinking to maximize
stability of the implant. Biologically, this approach is justified because
mechanical stimulation around a newly placed implant modulates the release of
bone mediators [16]. Indiscriminately and immediately loading of dental implants
is not always favourable because of unfavourable stress distribution and
non-favourable cellular response during initial healing phase in un-splinted
implants like in over dentures or partial fixed dental prosthesis [17]. Furthermore,
high torque during insertion of implant at an under drilled site which is
commonly used for immediate loading can reduce crestal bone-to-implant contact
during initial healing phase [18]. To reduce the chance of patient’s morbidity,
flapless surgery with the use of prefabricated customized guides are used. This
makes the surgery more accurate and avoids interference with anatomical
structures [19]. Primary stability is extremely important for
osseointegration which can be achieved by greater insertion torque. For this
splinting is recommended during a full arch restoration with immediate loading [20]. On contrary,
extra high insertion torque can lead to wearing on the implant surface and
cause a foreign body reaction because of titanium debris and ions that are
emitted from the implant surface [21].