implants - the journal of oral implantology UK Edition

16 I Icase report _ multiple implants implants1_2012 44 Roots - 44 Implants Author_ Drs Eduardo Topete A., Estela Topete Z., Eduardo Topete Z. & Alberto Topete Z. A case report _Various surgical techniques for bone augmenta- tion of the maxilla and mandible are mentioned in the literature. This article offers viable alternatives to maxillary and mandibular surgery, helping to prevent implant resorption in molar areas. _Back to roots: “Implantology 2000” The implantology profession agrees that a great- erm number of implants to support the prosthesis is a determining factor of success. A greater number of implants decreases the number of pontics, im- proves the biomechanics by reducing strain on the prosthesis and dissipates stresses more effectively to the bone structure, especially at the crestal level. The maximum osseous surface area and adequate bone density are requirements for long-term resistance to occlusal loads.7 In addition, the greatest functional surface area is required in the crestal 5mm of the im- plant body. Comparisons between natural tooth roots and implants show that increasing the surface area by increasing the number of implants is a prime re- quirement for achieving long-term success of dental implants.10 In the past, the replacement of one molar with a single implant was widely accepted as the recom- mended standard practice.8 As an innovative and viable alternative to the current standard practice, replacing mandibular molars with two implants and maxillary molars with three implants has been suc- cessfully applied since 1994, in other words one im- plant per root lost. This technique of using multiple implants preserves the natural crown–root ratio of molars. More importantly, multiple implants reduce and balance the occlusal forces. This reduction in oc- clusal forces greatly reduces implant–bone stress on the surface contact areas in the posterior regions of the mouth where the maximum stress is placed on the molars. In the 1980s, force reduction and surface area were difficult to balance in the posterior regions of the mouth. Studies clearly demonstrate that the forces are often 300 per cent greater in the poste- rior areas compared with the anterior regions of the mouth. Bone densities and strengths are 50 to 200 per cent weaker in the posterior regions of the mouth. Yet, implants with a greater surface area (accord- ing to length) were inserted in the anterior regions. Natural teeth do not have longer roots in the poste- rior regions of the mouth, where stresses are greater. Instead, increased surface area is achieved with a greater number of implants, placing two implants in each lost molar. In available bone of adequate width, replacing the lost roots with the same number of im- plants is recommended, placed in the same position and direction that nature created (within anatomic limitations),6 especially in cases in which only a few millimetres of bone remain between the cortical floor of the sinus and the crest of the ridge.10 This way, the distribution of the bite forces in key points proposed by Misch in his paper at the World Congress of Oral Implantology in Taipei in 2006 could be achieved using thin implants inserted in strategic positions, passing along the sides of the walls of the sinus to create a tripod to support the maxillary mo- Fig. 1 Fig. 2 Fig. 3 Fig 1_Jose Conte (1997). Fig 2_Jose Conte (2007). Fig 3_ I.P.S.P.S. diagram for implants of 3.26, 3.76 and 4.10mm in diameter.