Secondary Logo

Journal Logo

Clinical Science and Techniques

Implants for Single First Molar Replacement: Important Treatment Concerns

Carvalho, Waldimir CD*; Casado, Priscila Ladeira CD*; Caúla, André Luis CD, MScD; Barboza, Eliane Porto CD, MScD, DScD

Author Information
doi: 10.1097/01.id.0000148558.80761.bf
  • Free

Abstract

The first molars are the first permanent teeth to erupt in the mouth and unfortunately are often the first teeth to be lost as a result of decay. They are important teeth for maintenance of the arch form and for proper occlusal schemes.1 Nonetheless, the loss of a single molar is regarded as a common cause of a nonphysiological occlusion resulting from tipping of neighboring teeth and extrusion of opposing teeth. In visible sites, esthetic concerns also play a role in the treatment plan.2

Differences in anatomy, biomechanics, and microbiology make the treatment of partially edentulous jaws substantially different from that of totally edentulous jaws.3 In the past, options for replacement of a missing first molar involved either a removable or a fixed partial denture. A fixed bridge denture has been a well-accepted treatment modality. However, today it may be contraindicated to prepare healthy teeth proximal to an edentulous space for crowns.4

The survival of implant restorations in partially edentulous patients has been within ranges similar to those for implant survival in totally edentulous patients.5 The use of endosseous osseointegrated implants has continued to expand as a treatment option for a missing first molar. In many instances, the implant has emerged as the treatment of choice. A number of applications have evolved, and clinical and laboratory procedures continue to undergo refinement.6 However, the rehabilitation of the first molar region using dental implants has limited long-term clinical documentation and is still a challenge for those who practice implant dentistry. This requires a treatment plan based not only on the surgical aspects such as the distribution of the mesiodistal space related to implant diameter, but also on biomechanics.

This article discusses important aspects to plan a rehabilitation, using dental implants, in the area of first molars.

Longitudinal Studies of Implants Placed in the Posterior Region

There are numerous studies evaluating implants in partially edentulous patients; however, there are relatively few that evaluated implants placed into molar positions. Long-term success of endosseous implants placed both in the maxillary and mandibular posterior regions is inferior to other areas.7–9 Disadvantages to these regions include poor bone quality that can compromise initial implant stabilization and load transfer to the bone; the location of the maxillary sinus or the mandibular canal, which is frequently close and does not enable placement of long implants; the occlusal loads, which are higher; and the occlusal table, which is frequently wider than the implant diameter, resulting in mesiodistal and buccolingual cantilever and off-axis forces.10,11 The overall survival and success rates of long-term studies with implants placed at the posterior region of the maxilla and mandible are seen in Table 1.

T1-10
Table 1:
Long-Term Studies With Implants Placed at Posterior Maxilla and Mandible

Bone Quantity: The Shape and Contour of the Residual Alveolar Ridge

The quantity of available bone for implant placement is limited by the 3-dimensional shape and contour of the residual alveolar ridge. Atwood and Tallgren23,24 evaluated the characteristic bone volume changes after tooth loss. The authors concluded that the amount of bone loss occurring the first year after tooth loss is almost 10 times greater than the following years, and that the posterior mandible resorbs at a rate approximately 4 times faster than the anterior mandible. Localized ridge deformities are usually a consequence of the effects of previous dental infection-related bone loss, trauma during the extraction procedure, and alveolar bone remodeling after tooth extraction. The resulting alveolar ridge, often exhibiting reduced height and width, presents a considerable challenge to prosthetic reconstruction, in particular for placement of endosseous dental implants.

There are two distinct pathways in the attempt to replace first molars areas using dental implants: 1) preservation of osseous structures, placing (or not) an implant immediately into a fresh extraction socket, or 2) augmentation of osseous structures in deficient alveolar ridge sites for oral implant placement.

Preservation of the osseous structures in a site where a tooth extraction is performed results in simpler and more predictable placement of oral implants, simpler prosthetic restorations, a more favorable crown–root ratio for the oral implant-borne restorations, and simpler procedures leading to optimal aesthetic results.25 Placing an implant immediately into a fresh extraction socket neutralizes the waiting time of 6 to 8 months. The longitudinal clinical effectiveness of osseointegrated dental implants placed immediately into fresh extraction sites of first and second molar teeth has been reported.26 The 5-year cumulative survival rate was 82.3% in the maxilla and 92.3% in the mandible. A total of 14 implants were placed in maxillary first molar locations and 22 implants in mandibular first molar locations. Four implants were lost in the first molar region (three in the maxilla and one in the mandible). The authors of those articles concluded that immediate implantation in the molar region is a predictable treatment.

Indeed, implants placed immediately postextraction have proven to be a successful, predictable treatment modality.27 However, the immediate placement of fixtures is oftentimes limited by the quantity of bone that remains after the extraction, especially on those areas that the buccal plate is lost. The augmentation of a deficient alveolar ridge with regenerated bone has been achieved and does seem to be compatible with the osseointegration of endosseous implants. A number of different techniques to maintain the ridge or regenerate bone have been used. Guided bone regeneration has been performed to augment localized ridge deformities with resorbable and nonresorbable barriers.28–31 Placement of bone grafting materials in ridge augmentation has also been used with variable success.32–34

Bone Quality: Density in the Posterior Region

The density of bone is an important factor for an implant long-term success rate. When implants are placed in poor quality bone, there is a higher risk for implant failure.7 Generally, there is poor quality of bone in the posterior region. This is a major reason for the higher failure rate, compared with the anterior region.4 These conditions create a need to plan posterior single-tooth replacement using osseointegrated dental implants differently. This treatment plan should be guided by the bone density factor. Bone density in the posterior maxilla is generally type D4 or D3.10 In the mandible, it ranges from D2 to D4.10 This would lead to the choice of implant design and surface treatment developed specifically to such different types of bone density to increase the bone/implant contact area. Hydroxyapatite -prayed (HA) resorbable blast media or acid-attacked implant surfaces have been selected.

Other Anatomic Considerations

The Maxillary First Molar Region

The posterior maxilla has been described as the most difficult and problematic intraoral area for implant placement. Both anatomic features and mastication dynamics contribute to the challenge of placing implants in this region. Anatomic factors in the maxillary first molar region include decreased bone quantity and poor bone density, but also the presence of maxillary sinus or antrum, which limits the available bone height. This is especially important in implant therapy for older patients as a result of maxillary sinus pneumatization. A predictable approach to correct this condition is maxillary sinus floor elevation. This technique was first published by Boyne and James and later modified by others.35–42 This sinus floor elevation, formerly called sinus lifting, consists of a surgical procedure in which a top hinge door in the lateral maxillary sinus wall is prepared and internally rotated to a horizontal position. The new elevated sinus floor, together with the inner maxillary mucosa, will create a space that can be filled with graft material.

Ulm et al. evaluated the height and width of the available bone at the maxillary molar region.43 The mean ridge heights ranged between 9.30 and 3.23 mm, the highest and lowest values being 13.8 and 0.8 mm, respectively. The ridge widths generally proved to be sufficient for placement of endosseous implants.

The Mandibular First Molar Region

There is an anatomic structure in the posterior region of the mandible, relevant to the placement of osseointegrated implants. It is the mandibular canal. Therefore, a prerequisite for the implant surgery on the posterior region of the mandible is the localization of the mandibular canal. Even until today, panoramic radiography has remained the standard and simplest diagnostic method used to locate the mandibular canal. Although limitations of this technique are the distortion factor and that the buccolingual location of the mandibular canal cannot be obtained in the panoramic view. To obtain the more precise location of the mandibular canal, the clinician may use computed tomography (CT). Comparing the tomographic techniques with panoramic radiography, CT scans have been found to be more precise in measuring the distance between the bone crest and the mandibular canal compared with panoramic radiography,44 and the tomographic radiographs have an additional advantage in presurgical planning, because they reveal the horizontal dimension and shape of the mandible, and the topography and buccolingual location of the mandibular canal.

According to the report of Gowgiel45 on dissections of the inferior alveolar nerve, the neurovascular bundle from the mandibular foramen to the mental foramen is always in contact with, or in close proximity to, the lingual mandibular cortex. In the study of Tamas,46 the buccal position of the inferior alveolar nerve was observed only in 6% (10 of 164) of the mandibles.

In a study using 40 partially dentate mandibles, Oliveira et al.47 measured radiographically the distance between the residual alveolar process and the roof of the mandibular canal in the edentate region of the inferior first molar. The results showed an average distance of 14.7 mm. The authors concluded that in the majority of the cases, there is enough bone in height for osseointegrated implants.

Another important aspect when implants are placed in the posterior region is the lingual mandibular bone concavity first described by Mainous and Boyne.48 This anatomic mandibular structure increases the risks of fenestrations or perforations during implant installation, if a proper buccal–lingual angulation is not performed.

Biomechanical Concerns

Biomechanical concerns, in the area of first molars, concentrate on unfavorable stress distribution owing to bone density, anatomic reasons that lead to the placement of inadequate number and length of implants, and excessive loads compared with anterior regions. These factors may compromise osseointegration.5

Another important factor to be considered is that the maximum bite force differs from mastication force, varies widely among individuals, and depends on the state of dentition and masticatory musculature. It is interesting to note that the natural teeth are narrower in the anterior regions of the mouth, where the amount of force generated is less. The natural teeth increase in diameter in the premolar region and again in the molar region as the amount of force increases.49 Furthermore, the occlusal stress placed on the osseointegrated implant is very important to determine long-term success.50

Occlusal force correlates positively with muscle cross-sectional size, and it has long been known that unilateral occlusal forces increase as the bite point moves posteriorly,51 not only because the dental lever arm gets shorter, but because more muscles groups are active. Whereas masticatory forces of 155 N and 288 N have been reported in the incisor and premolar region, respectively, the molar region has exhibited 565 N.52 Parafunction can increase these forces as much as 3-fold,53,54 applying significant stress to the bone–implant interface. These values are just part of a wide range found in normal subjects.54

Implant Selection

The implant treatment options for the restorations of a single first molar tooth include: 1) a single narrow or medium-diameter implant, 2) a single wide-diameter implant, or 3) double narrow or medium-diameter implants.

Single Narrow/Medium Diameter Implant

Single narrow (3.0- to 3.5-mm) or medium (3.75- to 4.5-mm) implants are incapable of predictably withstanding molar masticatory function and occlusion loading forces. With the use of one small-diameter implant, even if it is long, to replace first molars, there will be a discrepancy between the implant length and width and the size of the restored crown. Placement of a crown that extends beyond the long axis of the implant could generate cantilevering forces on the crown and implant.55 Lateral forces create a bending moment relative to the implant at its marginal bone, and axial forces introduce bending if offset from the implant axis in a mesiodistal or buccolingual direction.56 These forces could contribute to screw loosening and eventual implant or abutment fatigue.55 In addition, the presence of a “cantilever” can make it difficult for home care and cause peri-implant bone loss.57

To reduce the risk of implant failure and increase the ability of posterior implants to tolerate occlusal forces, it may be beneficial to create a wider base. One option is the use of wider (5.0- to 6.0-mm) implants; the other is the placement of two narrow or medium-diameter implants at one site.58

Single Wide-Diameter Implant

Recently, Wang et al. evaluated the stress induced in the implants and peri-implant bone of a loaded molar supported by a wide-diameter implant or two standard/narrow-diameter implants.59 The models were designed to restore a 13-mm edentulous space using a 3-dimensional finite element method (FEM). Under horizontal loads, the maximal stress in bone and implant was highest in 3.25-mm-narrow-diameter implant, whereas the use of 5-mm-wide-diameter or two 3.75-mm implants was performed equally well.

The choice between 5-mm and double implants should be influenced by the quality and quantity of the bone, the amount of bone below the sinus or above the nerve in relation to the length of the implant that is desired, and the availability of adequate mesiodistal space (Table 2).

T2-10
Table 2:
Treatment Options to Replace Single First Molar Using Endosseous Implants

The wide-diameter implants were used initially to replace failed standard-diameter implants.60 Several advantages are derived from wider implant platforms at first molar areas: they have stronger screws, larger hex designs on flaptop implants, they support higher torque forces applied to retaining screws, internal hex, and octagon configurations, and combinations of these. These improvements have contributed to greater success with molar restoration.61 Wider-diameter implants have a distinct use in smaller molar spaces (8–11 mm) with a crestal width greater than or equal to 8 mm.62 A recent study recommended the use of wide implants cautiously and only when necessary.63 The disadvantage of starting with the wide-diameter implant is that if the implant fails to osseointegrate; a “rescue implant” or wider implant for immediate replacement is not available.4 Even more recently, Small et al. reported a distinct trend of soft tissue recession around wider implants compared with a standard-diameter implants.64

The success with wide-diameter implants in replacing molar teeth has been documented in clinical studies. In a 2-year study with 266 wide-diameter implants placed in a posterior region, Graves et al. reported a success rate of 98% in the maxilla and 94% in the mandible.65 In a retrospective report by Becker and Becker,55 on the replacement of single molars with implant-supported restorations in 22 patients using 24 wide-diameter implants, a cumulative success rate of 95% was achieved (only one implant was lost).

Double Narrow/Medium-Diameter Implants

In 1990, Balshi suggested placement of two implants in first molar position to compensate for poor-quality bone usually found at the posterior region.66 Double implants more closely mimic the anatomy of the roots being replaced and doubles the anchorage surface area. Other advantages include: elimination of the anterior–posterior cantilever, reduction of the rotational forces exerted, and reduction of screw loosening. However, daily oral hygiene may be more difficult, and is the major limitation of placing two implants continuously to be insufficient mesiodistal space. According to Saaduon et al.,67 a minimum of 12.5 to 14.0 mm of interdental space is needed to successfully replace double standard implants for a missing molar. Ideally, the interproximal region between the implant body and adjacent natural tooth roots should be at least 1.5 to 2 mm to accommodate for the surgical, periodontal, and prosthetic requirements.49 More recently, it was demonstrated that there is a lateral component to the bone loss after abutment connection of a 2-stage implant. This lateral component can result in greater interimplant crestal bone loss if the two implants are not spaced more than 3 mm apart.68 When 11 to 12.5 mm of mesiodistal space is present, additional space may be gained to allow placement of double implants. The options include: 1) enameloplasty of the adjacent tooth, which often can be up to 0.5 mm on each tooth; or 2) orthodontic repositioning to upright a tilted second molar or increase intertooth space.4,50 Misch also suggested placing implants on a diagonal position when there is insufficient interdental space and the ridge width is wide. The diagonal dimension is then increased by 0.5 to 1.0 mm.50 In the mandible, the most anterior implant is placed to the lingual aspect of the crest, and the more distal implant is placed toward the facial aspect to facilitate access of a floss threader from the vestibule into the interimplant space. The occlusal contacts are also slightly modified on the buccal aspect of the central fossa. For the maxilla, the anterior implant is placed toward the buccal aspect and the distal implant toward the palate to improve the aesthetics of the more visible half of the tooth. The distal occlusion contact is placed over the lingual cusp, and the mesial occlusal contact is located in the central fossa position.1

Single versus Double Implants

Several clinical studies have been conducted to compare single wide-diameter and double standard implants. Balshi et al. compared the use of one single-wide implant with the use of two implants to replace a single molar.56 The 3-year cumulative success rate was 99% with 0.1-mm marginal bone loss for one implant and 0.24 mm with two implants. The authors hypothesize that the decreased access between the implants in the two-implant group could be a contributing factor for bone loss. However, this was not supported by clinical observations or the bleeding index, which both demonstrated very healthy soft tissue in this area. Prosthesis mobility and screw loosening were the most common complications for the one-implant group (48%) and were reduced to 8% in the two-implant group. In the same year, Bahat and Handelsman reported higher failure rates for single wide-diameter implant (2.3%) as compared with double implants (1.6%) placed in the posterior region.58

Conclusions

Management of the first molar region presents many challenges for the implant practitioner. A preliminary detailed planning is of particular importance. This includes detailed analysis of anatomic features, soft tissue management, and adequate selection of number, diameter, length, and surface of the implants. Based on the scientific literature, restoring first molars with one wide-diameter implant or double implants provides more surface area and better biomechanical properties than single narrow or medium-diameter implants.

Disclosure

The authors claim to have no financial interest in any company or any of the products mentioned in this article.

References

1. Misch CE. Endosteal implants for posterior single tooth replacement: alternatives, indications, contraindications, and limitations. J Oral Implantol. 1999;25:80–94.
2. Avivi-Arber L, Zarb GA. Clinical effectiveness of implant supported single tooth replacement: the Toronto Study. Int J Oral Maxillofac Implants. 1996;11:311–321.
3. Parein AM, Eckert SE, Wollan PC, et al. Implant reconstruction in the posterior mandible: A Long-term Retrospective Study. J Prosthet Dent. 1997;78:34–42.
4. Balshi TJ, Wolfinger GJ. Two-implant-supported single molar replacement: interdental space requirements and comparison to alternative options. Int J Periodont Rest Dent. 1997;17:427–435.
5. Muftu A, Chapman RJ. Replacing posterior teeth with freestanding implants: four-year prosthodontic results of a prospective study. JADA. 1998;129:1097–1102.
6. Henry PJ, Jemt T, Krogh PHJ, et al. Osseointegrated implants for single-tooth replacement: a prospective 5-year multicenter study. Int J Oral Maxillofac Implants. 1996;11:450–455.
7. Jaffin RA, Berman CL. The excessive loss of Branemark fixtures in type IV bone: a 5-year analysis. J Periodontol. 1991;62:2–4.
8. Engquist B, Bergendal T, Kallus T, et al. A retrospective multicenter evaluation of osseointegrated implants supporting overdentures. Int J Oral Maxillofac Implants. 1988;3:129–134.
9. Scurria MS, Morgan ZV IV, Guckes AD, et al. Prognostic variables associated with implant failure: a retrospective effectiveness study. Int J Oral Maxillofac Implants. 1998;13:400–406.
10. Misch CE. Contemporary Implant Dentistry, 2nd ed. St. Louis: CV Mosby Co; 1999:109–118.
11. Misch CE. Contemporary Implant Dentistry, 2nd ed. St. Louis: CV Mosby Co; 1999:193–204.
12. van Steenberghe D, Lekholm U, Bolender C, et al. Applicability of osseointegrated oral implants in the rehabilitation of partial edentulism: a prospective multicenter study on 558 fixtures. Int J Oral Maxillofac Implants. 1990;5:272–281.
    13. Zarb GA, Schmitt A. The longitudinal clinical effectiveness of osseointegrated dental implants in posterior partially edentulous patients. Int J Prosthodont. 1993;6:189–196.
      14. Bahat O. Treatment planning and placement of implants in the posterior maxillae: report of 732 consecutive Nobelpharma implants. Int J Oral Maxillofac Implants. 1993;8:151–161.
        15. Bernard JP, Belser UC, Szmukler S, et al. 3-year success rates of short ITI implants in posterior jaws. Médecine Buccale et Chirurgie Buccale. 1995;1:11–18.
          16. Grunder U, Polizzi G, Goene R, et al. A 3-year prospective multicenter follow-up report on the immediate and delayed-immediate placement of implants. Int J Oral Maxillofac Implants. 1999;14:210–216.
            17. Testori T, Del Fabbro M, Feldman S, et al. A multicenter prospective evaluation of 2-months loaded Osseotite implants placed in the posterior jaws: 3-year follow-up results. Clin Oral Implants Res. 2002;13:154–161.
              18. Haas R, Polak C, Fürhauser R, et al. A long-term follow-up of 76 Brånemark single-tooth implants. Clin Oral Impl Res. 2002;13:38–43.
                19. Becker W, Becker BE, Alsuwyed A, et al. Long-term evaluation of 282 implants in maxillary and mandibular molar positions: a prospective study. J Periodontol. 1999;70:896–901.
                  20. Buser D, Mericske-Stern R, Bernard JP, et al. Long-term evaluation of non-submerged ITI implants. Part 1: 8-year life table analysis of a prospective multi-center study with 2359 implants. Clin Oral Implants Res. 1997;8:161–172.
                    21. Bahat O. Branemark system implants in the posterior maxilla: clinical study of 660 implants followed for 5 to 12 years. Int J Oral Maxillofac Implants. 2000;15:646–653.
                      22. Block MS, Gardiner D, Kent JN, et al. Hydroxyapatite-coated cylindrical implants in the posterior mandible: 10-year observations. Int J Oral Maxillofac Implants. 1996;11:626–633.
                        23. Atwood DA. Reduction of residual ridges: a major oral disease entity. J Prosthet Dent. 1971;26:266–279.
                        24. Tallgren A. The continuing reduction of the residual alveolar ridges in complete denture wearers: a mixed-longitudinal study covering 25 years. J Prosthet Dent. 1972;27:120–132.
                        25. Adriens PA. Preservation of bony sites. In: Lang NP, Karring T, Lindhe J, eds. Proceedings of the 3rd European Workshop on Periodontology. Berlin: Quintessence; 1999:266–280.
                        26. Schwartz-Arad D, Grossman Y, Chaushu G. The clinical effectiveness of implants placed immediately into fresh extraction sites of molar teeth. J Periodontol. 2000;71:839–844.
                        27. Block MS, Kent JN. Placement of endosseous implants into extraction sites. J Oral Maxillofac Implants. 1991;49:1269–1276.
                        28. O’Brien TP, Hinrichs JE, Schaffer EM. The prevention of localized ridge deformities using guided tissue regeneration. J Periodontol. 1994;65:17–24.
                        29. Lekovic V, Camargo PM, Klokkevold PR, et al. Preservation of alveolar bone in extraction sockets using bioabsorbable membranes. J Periodontol. 1998;69:1044–1049.
                        30. Barboza EP. Localized ridge maintenance using bone membrane. Implant Dent. 1999;8:167–172.
                        31. Bartee BK. Extraction site reconstruction for alveolar ridge preservation. Part 2: membrane-assisted surgical technique. J Oral Implantol. 2001;27:194–197.
                        32. Barboza EP. Clinical and histologic evaluation of the demineralized freeze-dried bone membrane used for ridge augmentation. Int J Periodontics Restorative Dent. 1999;19:601–607.
                        33. Barboza EP, Duarte ME, Geolas L, et al. Ridge augmentation following implantation of recombinant human bone morphogenetic protein-2 in the dog. J Periodontol. 2000;71:488–496.
                        34. Barboza EP, de Souza RO, Caula AL, et al. Bone regeneration of localized chronic alveolar defects utilizing cell binding peptide associated with anorganic bovine-derived bone mineral: a clinical and histological study. J Periodontol. 2002;73:1153–1159.
                        35. Boyne PJ, James RA. Grafting of the maxillary sinus floor with autogenous marrow and bone. J Oral Surg. 1980;38:613–616.
                        36. Tatum OH. Maxillary sinus and implant reconstruction. Dent Clin North Am. 1986;30:207–229.
                        37. Misch CE. Maxillary sinus augmentation for endosteal implants: organized alternative treatment plans. Int J Oral Implantol. 1987;4:49–58.
                        38. Smiler DG, Holmes RE. Sinus lift procedure using porous hydroxyapatite: a preliminary report. J Oral Implantol. 1987;13:239–253.
                        39. Wood R, Moore D. Grafting of the maxillary sinus with intraorally harvested autogenous bone prior to implant placement. Int J Oral Maxillofac Implants. 1988;3:209–214.
                        40. Kent JN, Block MS. Simultaneous maxillary sinus floor bone grafting and placement of hydroxylapatite-coated implants. J Oral Maxillofac Surg. 1989;47:238–242.
                        41. Summers RB. A new concept in maxillary implant surgery: the osteotome technique. Compend Contin Educ Dent. 1994;15:152–160.
                        42. Summers RB. The osteotome technique: part 3. Less invasive methods of elevating the sinus floor. Compend Contin Educ Dent. 1994;15:698–708.
                        43. Ulm CW, Solar P, Gsellmann B, et al. The edentulous maxillary alveolar process in the region of the maxillary sinus—a study of physical dimension. Int J Oral Maxillofac Surg. 1995;24:279–282.
                        44. Tal H, Moses O. A comparison of panoramic radiography with computed tomography in the planning of implant surgery. Dentomaxillofac Radiol. 1991;20:40–42.
                        45. Gowgiel JM. The position and course of the mandibular canal. J Oral Implantol. 1992;18:383–385.
                        46. Tamas F. Position of the mandibular canal. Int J Oral Maxillofac Surg. 1987;16:65–69.
                        47. Oliveira SHG, Leite HF, Menezes ACS, et al. Study of the localization of the mandibular canal in the edentate region of the lower first molar. Rev Assoc Paul Cir Dent. 2000;54:372–374.
                        48. Mainous EG, Boyne PJ. Lingual mandibular bone concavity. JADA. 1975;90:666–668.
                        49. Misch CE. Contemporary Implant Dentistry, 2nd ed. St. Louis: CV Mosby Co; 1999:119–134.
                        50. Misch CE. Contemporary Implant Dentistry, 2nd ed. St. Louis: CV Mosby Co; 1999:397–428.
                        51. Koolstra JH, Van Eijden TMGJ. Application and validation of a three-dimensional mathematical model of the human masticatory system in vivo. J Biomech. 1992;25:175–187.
                        52. Martel MH. About single units, abutments, and interlocks, implants and experts. Presented at the American Academy of Fixed Prosthodontics; Chicago; February 19–20, 1993.
                        53. Gibbs C, Mahan P, Mauderli A. Limits of human bite strength. J Prosthet Dent. 1986;56:226–237.
                        54. Hagberg C. Assessments of bite force: a review. J Craniomandib Disod Facial Oral Pain. 1987;1:162–169.
                        55. Becker W, Becker BE. Replacement of maxillary and mandibular molars with single endosseous implant restorations: a retrospective study. J Prosthet Dent. 1995;74:51–55.
                        56. Balshi TJ, Hernandez RE, Pryszlak MC, et al. A comparative study of one implant versus two replacing a single molar. Int J Oral Maxillofac Implants. 1996;11:372–378.
                        57. Sullivan DY. Wide implants for wide teeth. Dent Econ. 1994;84:82–83.
                        58. Bahat O, Handelsman M. Use of wide implants and double implants in the posterior jaw: a clinical report. Int J Oral Maxillofac Implants. 1996;11:379–386.
                        59. Wang TM, Lee MS, Chang CF, et al. Restore a molar with one or two implants. A finite element analysis. The 81st General Session of the International Association for Dental Research; Goteborg, Sweden; June 25–28, 2003.
                        60. Langer B, Langer L, Herrmann I, et al. The wide fixture: a solution for special bone situations and a rescue for the compromised implant. Part 1. Int J Oral Maxillofac Impl. 1993;8:400–408.
                        61. Binon PP. Implants and components: entering the new millennium. Int J Oral Maxillofac Implants. 2000;15:76–94.
                        62. Davarpanah M, Martinez H, Kebir M, et al. Wide-diameter implants: new concepts. Int J Periodontics Restorative Dent. 2001;21:149–159.
                        63. Ivanoff CJ, Gröndahl K, Sennerby L, et al. Influence of variations in implant diameters. A 3- to 5- year retrospective clinical report. Int J Oral Maxillofac Implants. 1999;14:173–180.
                        64. Small PN, Tarnow DP, Cho SC. Gingival recession around wide-diameter versus standard-diameter implants: a 3- to 5- year longitudinal prospective study. Pract Proced Aesthet Dent. 2001;13:143–146.
                        65. Graves SL, Jansen CE, Siddiqui AA, et al. Wide diameter implants: indications, considerations and preliminary results over a two-year period. Aust Prosthodont J. 1994;8:31–37.
                        66. Balshi TJ. First molar replacement with an osseointegrated implant. Quintessence Int. 1990;21:61–65.
                        67. Saadoun AP, Sullivan DY, Krischek M, et al. Single tooth implant—management for success. Pract Periodontics Aesthet Dent. 1994;6:73–80.
                        68. Tarnow DP, Cho SC, Wallace SS. The effect of inter-implant distance on the height of inter-implant bone crest. J Periodontol. 2000;71:546–549.

                        Abstract Translations [German, Spanish, Portugese, Japanese]

                        AUTOR(EN): Waldimir Carvalho, CD*, Priscila Ladeira Casado, CD*, André Luis Caúla, CD, MScD**, Eliane Porto Barboza, CD, MScD, DScD***. * Student der Abschlussklasse, UFF, Rio de Janeiro, Brasilien. ** Leiter der zahnärztlichen Betreuung, staatliche Feuerwehr Rio de Janeiro, Rio de Janeiro, Brasilien. *** Stellvertretende Vorsitzende, MSc. im Zahnheilkundeprogramm, zahnmedizinische Fakultät, staatliche Fluminense Universität, Rio de Janeiro, Brasilien. Direktor, brasilianisches Institut für Parodontologie, Rio de Janeiro, Brasilien. Schriftverkehr: Waldimir Carvalho, CD, Av. Presidente Wilson 165/810, Centro, Rio de Janeiro, RJ Brasilien - CEP: 20030 –020. Telefon/Fax: 55 21 22206940 / 22206706. eMail:[email protected]

                        Einzelzahnimplantierung zum Ersatz der vorderen Mahlzähne: wichtige Behandlungsgrundlagen

                        ZUSSAMENFASSUNG: Allgemein verzeichnet man eine geringere Erfolgsquote bei Implantierungsbehandlungen im hinteren Kieferbereich als bei Implantatverwendung im vorderen Ober -oder Unterkiefer. Spezifische anatomische Gegebenheiten, die Eigendynamik des Kauvorgangs sowie die Auswahl des geeigneten Implantats spielen eine wesentliche Rolle für den langfristigen Erfolg einer Implantierungsbehandlung im Bereich der Mahlzähne. Der vorliegende Artikel befasst sich mit der Diskussion wichtiger Aspekte zur Anwendungsplanung von Zahnimplantierungen im Bereich der vorderen Mahlzähne.

                        SCHLÜSSELWÖRTER: Zahnimplantate, hinterer Oberkiefer, hinterer Unterkiefer, Einzelzahn, Behandlungsplan

                        AUTOR(ES): Waldimir Carvalho, CD*, Priscila Ladeira Casado, CD*, André Luis Caúla, CD, MScD**, Eliane Porto Barboza, CD, MScD, DScD***. *Estudiante Graduado, UFF, Rio de Janeiro, Brasil. **Teniente Primero Dentista, Departamento de Bomberos del Estado de Rio de Janeiro, Rio de Janeiro, Brasil. ***Subjefa, Programa de Maestría en Ciencias en Odontología, Facultad de Odontología –Federal Fulminense University, Rio de Janeiro, Brasil. Director –Instituto Brasilero de Periodontología, Rio de Janeiro, Brasil. Correspondencia a: Waldimir Carvalho, CD, Av. Presidente Wilson 165/810, Centro, Rio de Janeiro, RJ Brazil –CEP: 20030–020. Teléfono/fax: 55 21 22206940 / 22206706, Correo electrónico:[email protected]

                        Implantes para el reemplazo de un primer molar solo: Cuestiones importantes sobre el tratamiento

                        ABSTRACTO: Las tasas de éxito de los implantes colocados en la parte posterior de ambas mandíbulas es menos que para los segmentos anteriores. Características anatómicas, la dinámica de la masticación y una selección adecuada del implante son todos importantes factores para la prognosis a largo plazo en la región molar. Este artículo explica aspectos importantes en la planificación del uso de implantes dentales en las zonas de los primeros molares.

                        PALABRAS CLAVES: implantes dentales, maxilar posterior, mandíbula posterior, diente único, plan de tratamiento

                        AUTOR(ES): Waldimir Carvalho, Cirurgião-Dentista*, Priscila Ladeira Casado, Cirurgião-Dentista*, Andráe Luis Cauúla, Cirurgião-Dentista, Mestre em Odontologia,**, Eliane Porto Barboza, Cirurgiã-Dentista, Mestre em Odontologia, Doutora em Odontologia***. * Mestrandos em Odontologia, UFF, Rio de Janeiro, Brasil. ** Primeiro-Tenente Dentista, Corpo de Bombeiros do Rio de Janeiro, Rio de Janeiro, Brasil. *** Vice-Coordenadora do Programa de Mestrado em Odontologia, Faculdade de Oodntologia, Universidade Federal Fluminense, Rio de Janeiro, Brasil, e Diretora do Instituto Brasileiro de Periodontia, Rio de Janeiro, Brasil. Correspondência para: Waldimir Carvalho, CD, Av. Presidente Wilson 165/810, Centro, Rio de Janeiro, RJ Brasil –CEP: 20030–020. Teléfono:/Fax: 55 21 22206940 / 22206706. E-mail:[email protected]

                        Implantes para Substituição Única de Primeiro Molar: Preocupações Importantes com Tratamento

                        RESUMO: As taxas de êxito de implantes colocados na região posterior de ambos os maxilares são menores que os segmentos anteriores. Características anatômicas, dinamica de mastigação e seleção adequada de implante são todas significativas para prognóstico de longo prazo na região molar. Este artigo discute aspectos importanes no planejamento do uso de implantes dentários nas áreas dos primeiros molares.

                        PALAVRAS-CHAVE: implantes dentários, maxila posterior, mandíbula posterior, dente único, plano de tratamento.

                        FU1-10
                        Figure
                        Keywords:

                        dental implants; posterior maxilla; posterior mandible; single tooth; treatment plan

                        © 2004 by Lippincott Williams & Wilkins, Inc.