, neither buccolingual width nor angulation can be properly visualized on the most traditional radiographs . in the following case report , an innovative simplified method without radiation
is used to fabricate a three - dimensional model to assess the available bone for implant placement in the mandible .
even a minor variation in comparison to ideal placement causes difficulties in fabrication of final prostheses .
the surgical guide is essential to establish a logical continuity among diagnosis , prosthetic planning , and surgical phase .
a patient of age 27 years reported to the department of prosthodontics for the replacement of missing left first molar .
following steps were performed to achieve a three - dimensional model : 
 intraoral impression was recorded with addition silicone putty and light body [ figure 1]fabrication of acrylic assembly for aligning both intraoral and extraoral impressiona rectangular block of acrylic was made to which impression tray was pressed to make indentations . after applying separating medium
, the counter block of acrylic was made to which extraoral impression was attached [ figure 2 ] . in prototype ,
[ figures 24 ] plastic rod was used for supporting the extraoral impressionreplacing the plastic rod with metal plate and key system the plastic rod was replaced by a metal plate in the first generation [ figure 5 ] for better stability and better customization .
a key system was incorporated to adjust the length and angulation according to each patient 's mandible . on the top of the metal plate ,
addition silicone putty placed on the acrylic plate can be customized each time to record the extraoral impression .
the extraoral impression should record the lower border of the mandible to the medial extent as much as possible [ figure 6]fabrication of three - dimensional model the intraoral impression was poured first to get a cast . after the initial setting was over , the entire assembly was poured , and a three dimensional model of the mandible was fabricated [ figure 7 ] . 
 
intraoral impression was recorded with addition silicone putty and light body [ figure 1 ] fabrication of acrylic assembly for aligning both intraoral and extraoral impression a rectangular block of acrylic was made to which impression tray was pressed to make indentations . after applying separating medium , the counter block of acrylic was made to which extraoral impression was attached [ figure 2 ] . in prototype ,
[ figures 24 ] plastic rod was used for supporting the extraoral impression replacing the plastic rod with metal plate and key system the plastic rod was replaced by a metal plate in the first generation [ figure 5 ] for better stability and better customization .
a key system was incorporated to adjust the length and angulation according to each patient 's mandible . on the top of the metal plate , acrylic
addition silicone putty placed on the acrylic plate can be customized each time to record the extraoral impression .
the extraoral impression should record the lower border of the mandible to the medial extent as much as possible [ figure 6 ] fabrication of three - dimensional model the intraoral impression was poured first to get a cast . after the initial setting was over , the entire assembly was poured , and a three dimensional model of the mandible was fabricated [ figure 7 ] .
intraoral impression with acrylic assembly prototype ( extraoral impression ) prototype - extraoral and intraoral impression together with acrylic assembly first generation metal plate assembled metal frame three - dimensional model the accuracy of this method was verified with computed tomography ( ct ) scan .
the cross section where the mandibular premolar teeth were disappearing from the ct image was taken ( 14 mm depth ) as a reference and measured to get the available bone width buccolingually ( 8.7 mm ) .
this measurement was same when compared with the available bone in the sectioned cast at the premolar area , at a depth of 14 mm ( premolar root length ) .
on the three - dimensional model , the surgical guide was fabricated [ figure 8 ]
. this surgical template can dictate the implant body placement that offers the best combination of support for the repetitive forces of occlusion and esthetics .
three - dimensional model with surgical guide this article had won the best table clinic award in 35 ips conference conducted in new delhi 2007 by army dental corps .
 the primary factor that determines the success of implant is the amount of available bone in the edentulous site . diagnostic imaging and techniques help to develop and implement a cohesive and comprehensive treatment plan according to the available bone . in the following case 
 report an innovative simplified method ( poor man ct ) is used to fabricate a three dimensional model to assess the available bone for implant placement in mandible . 
INTRODUCTION
CASE REPORT
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