Book ReviewsDental Implants:The Art andScience

Edited by Charles A. Babbush, DDS, MscD. W.B. Saun-

ders Co., Philadelphia, PA, 2001: ISBN 0-7216-7747-9,

552 pages; 1112 mostly color illustrations; price $205

The editor of this book has attempted to com-municate a large amount of information regard-ing treatment planning, surgical placement, pros-thetic treatment, maintenance and hygiene, and afuture vision of the “cyber office’’ regarding dentalimplants. The broad approach does not target aspecific audience, however, and this tone mightbest be used as a supplemental atlas or referencefor the general practitioner. Because the editorand principal author is an oral surgeon, the bulkof this text (11 of the 25 chapters) is devoted tosurgical techniques. Dr. Babbush has previouslywritten two well-known textbooks, Surgical Atlas

of Dental Implant Techniques, and Dental Implants:

Principles and Practice.The text of 532 pages includes three fore-

words and a “Preface and Acknowledgements’’ byDr. Babbush. The index is 25 pages, and eachchapter has an extensive reference list. Thereare 33 authors, and the book is divided into5 sections: “Case Selection and Evaluation’’ (5chapters), “Surgical Techniques’’ (11 chapters),“Prosthetics’’ (3 chapters), “Maintenance and Hy-giene’’ (3 chapters), and “The Cyber Office’’ (3chapters).

Dr. Babbush states in the preface, “If the pa-tient does not comprehend or cooperate in the

daily home care process and return for the pro-fessional visitation and evaluation, the long-rangefavorable prognoses of these cases are seriouslycompromised.’’ The first chapter, written by Dr.Babbush, continues with the premise of “poor oralhygiene’’ and its effect on treatment selection. Forexample, a figure is presented with the followingtext: “Patient is a poor potential candidate forimplant reconstruction. Hopeless teeth should beremoved, area is temporized, and patient is placedon a vigorously controlled program of oral hy-giene.’’Members of the Prosthodontics communityreading this text may note that inappropriatedescriptive terminology is often used, such as thereference to an “omnivac suck-down splint,’’ whenperhaps a more correct use of accepted dentalnomenclature such as a “diagnostic vacuform tem-plate’’ would be more pleasing to an audience oftrained Specialists.

The “home care’’ concept again surfaces inChapter 6B, “Implant Periabutment Tissue,’’ byDr. Donald Callan. He merges literature on pe-riodontal and implant concepts regarding at-tached tissue and his own experience with state-ments such as, “Rather, implants fail because ofthe patient’s inability to clean properly aroundthe implants and because of possible develop-ment of perimucocitis.’’ In the opinion of thisreviewer and many colleagues, there is presentlyno clear scientific evidence relating “patienthome care’’ and the loss of dental implants.The author goes on to state, however, “There-fore it is logical to establish a region of at-tached keratinized gingival around the dentalimplant to create a more functional soft tissuebarrier,’’ citing Drs. Garnick and Silverstein.1

In the chapter summary, the author states, “Softtissue maintenance is the primary line of defensein protecting against bacterial infection aroundteeth and, especially, dental implants.’’ The au-thor promotes use of acellular dermal matrix toincrease the width of attached keratinized tissuearound implants. He cites several published nonpeer-reviewed papers and continues the home care

Journal of Prosthodontics, Vol 13, No 4 (December), 2004: pp 279-285 279

280 Book Reviews

mantra of the previous chapters with statementssuch as “Bacterial plaque is a prime etiologiccontributor to the loss of dental implants. Like gin-givitis, peri-implant mucositis is reversible oncethe etiologic agent – bacterial plaque – is re-moved. If allowed to progress, peri-implantitismay ensue,’’ and, “If the patient has a retrievablesuperstructure, it should be removed every 18–24 months and placed in an ultrasonic cleaningsolution.’’ 2

Section III, “Prosthetics,’’ begins with a briefsurvey by Dr. Peter S. Wohrle entitled “Principlesof Aesthetic Implant Dentistry.’’ It is followed by“Efficient Implant Prosthodontic Therapy’’ by Dr.Kenneth W. M. Judy, in which the author stressesthe importance of “unbroken models’’ and the useof cast verification jigs and cast corrective reduc-tion copings to ensure efficient and rapid com-pletion of implant prostheses, which invariablyseem to be cement-retained. The final chapter,“Transitional Phase: Patient Management WithTransitional Implants’’ by Dr. Paul S. Petrungaro,a periodontist, is comprised primarily of an em-phasis upon the surgical aspects of this treatmentmodality.

Certainly, Dr. Babbush has made an effort totransfer a large amount of knowledge regard-ing implantology in this text and has succeededin this regard when the topic is mostly surgi-cally oriented. I cannot recommend this bookfor Prosthodontists, however, as the informationrelating to dental restoration with implants isminimal.

Kenneth S. Kurtz, DDSClinical Associate Professor, International Program

in Prosthodontics, New York University College of

Dentistry, New York, NY and Assistant Professor,

Departments of Dentistry and Otolaryngology,

Montefiore Medical Center/Albert Einstein College of

Medicine, The Bronx, NY

References

1. Garnick J, Silverstein L: Periodontal probing: Whatdoes it mean?. Clark’s Clinical Dentistry 1996;3:1

2. Meffert R: Implantology and the dental hygienist’s role.J Pract Hyg 1995;4:12

ImplantOverdentures:The Standard ofCare forEdentulousPatients

Editors: Jocelyne S. Feine, Gunnar E. Carlsson.

Quintessence Publishing Co. Inc., Carol Stream, IL,

2003: ISBN 0-86715-430-6, 162 pp., 62 illustrations

(many black/white tables/graphs/radiographs, many color

images and illustrations); price $58, soft cover

This book is written to provide the evidence-based information to both the student andthe experienced clinician for treating edentu-lous patients with anterior mandible two-implantoverdentures. A symposium on the two-implantoverdenture held at McGill University, Montreal,Quebec, Canada in May 2002 produced a consen-sus statement that the two-implant overdentureshould become the first choice of treatment forthe edentulous mandible.

The editors, Drs. Gunnar E. Carlsson andJocelyne S. Feine, arranged the 14 chapters ina logical order to build support for the con-sensus statement. The first half of the book isdevoted to providing evidence to support theuse of two-implant retained overdentures. Thelatter half of the text addresses issues of two-implant overdenture treatment. Throughout thetext, the editors do an excellent job of ensuringthat the authors adhere to a recurring theme:adopting a patient-centered approach to treatingedentulism.

The text begins with a succinct discussion byDr. Philippe Mojon of past, current, and futuretrends in edentulism and the necessity of prepar-ing for the continued treatment of the edentu-lous patient. At the patient level, consideration isgiven to the effects of age, gender, income, health,lifestyle, and socioeconomic and psychosocial fac-tors on edentulism rates. The effects of a country’s

December 2004, Volume 13, Number 4 281

economic development, urban versus rural set-ting, and density of dentists provide a broaderperspective on the rate of edentulism. The readerneeds to pay close attention to the data sources,as it can be confusing when comparing statisticsfor different countries. This discussion ends with avery clear summary and concise conclusion, whichsupports the future need for treatment of theedentulous patient for the next 10–20 years.

The second chapter serves to explain the in-terrelationship between the masticatory process,nutrition, and edentulism. Correlation is madebetween implant prostheses, conventional den-tures, chewing ability, and food selection patterns.A thorough review of the literature is presentedto illustrate the relationship between numberof teeth and nutrient intake. Although the au-thors (Drs. J. A. Morais and J. M. Thomason)state that there is no data to date suggestingthat changes in eating patterns from implant-supported prostheses will result in changes in pa-tients’ nutritional status, they present the resultsof a pilot study indicating that a mandibular two-implant overdenture improves nutritional status,as evidenced by improved blood and anthropomet-ric measures at 6 months posttreatment whencompared to the conventional complete denturegroup. The authors of this chapter are carefulto indicate that these initial findings need to beconfirmed with larger randomized clinical trials.This chapter left the impression that the patientwill benefit from the two-implant mandibularoverdenture.

Dr. Michael MacEntee reiterates the expectedtrend for edentulism during the next quartercentury, but addresses edentulism from the pa-tients’ perspective of psychosocial and quality oflife issues. He suggests that edentulism affectspatients’ quality of life, and discusses this from4 perspectives: psychologic health and function,socioeconomic status, life satisfaction, and self-esteem. Implant overdentures can help alleviatethe suffering from dysfunction, pain, low self-esteem, and a reduced QOL.

Dr. Manal A. Awad observes the need toevaluate the success of treatment with morepatient-centered criteria rather than just clini-cal outcomes. He cites literature to support thepoor association between clinical excellence andpatients’ satisfaction with their prostheses, and astronger association between patients’ perceivedmasticatory ability and satisfaction with their

prostheses. This precedes a good discussion of theinterrelationship between patients’ expectationsof outcome, knowledge, preferences, and percep-tions of treatment.

Drs. Jocelyne S. Feine and Guido Heydeckestress the importance of recognizing the prioritiesof complete denture patients rather than evaluat-ing the success of treatment with the traditionalclinical parameters. They present literature tosupport the two-implant overdenture in provid-ing an improved quality of life, oral health, andfunction as compared to conventional completedentures.

Thus far, the reader has been furnished in-formation to support the use of the two-implantoverdenture as an improvement over conventionalcomplete dentures, but the question of expenseand affordability has not been described. Drs.J. R. Penrod and Yoshiaki Takanashi recognizethat since edentulous patients tend to come fromhouseholds of below-average income, if implant-retained overdentures are to become the standardof care for the edentulous patient, more afford-able, cost-effective implant treatments need tobe developed. The first step in this process is toidentify the costs for implant care through yearone as compared to conventional complete den-ture therapy. The authors review the cost analysisof two-implant overdentures compared to conven-tional complete dentures in conjunction with arandomized controlled clinical trial comparing theefficacy of two-implant overdentures to conven-tional dentures. The overdenture/conventionalcomplete denture cost ratio (using direct costsonly) is studied to facilitate the comparison oftheir data with studies from other countries.The authors specifically identify the shortcomingsin their study that make comparison to othercited studies impossible. They emphasize theneed for long-term data for a complete economicevaluation.

Assuming the demand for implant overden-tures increases in the coming decade, one mightalso assume the number of implant systems inthe marketplace will increase. Corporate claims ofimproved performance, ease-of-use and cost effec-tiveness may further confuse the selection of thebest implant system for patient care. The editors’expert clinical insight is evidenced by includinga chapter (by Dr. T. W. Head) with guidelineson simplifying the process of selecting an implantsystem for clinical practice. Suggestions are given

282 Book Reviews

on developing a system to evaluate and select themost appropriate implant system for the patient.

The remaining text focuses more directly onthe implant overdenture strategies with continuedreinforcement of the need to evaluate total treat-ment result, which includes patient satisfaction,amount of aftercare, and clinical performance ofthe different implant treatment strategies. Drs. D.Wismeijer and G. T. Stoker review a randomizedcontrolled clinical trial (Breda Implant Overden-ture Study) and make recommendations for theimplant overdenture strategy they deem best. Asseen in previous chapters, the authors indicate fur-ther long-term evaluation is necessary to confirmtheir suggestions.

The predictable implant overdenture treat-ment depends on thorough treatment planningand following sound complete denture principles.Dr. T. D. Taylor offers practical guidelines fortreatment planning overdentures with dental im-plants. The author suggests offering dental im-plants as a means of increasing patient satisfac-tion and improving the quality of life with anextremely thorough and systematic approach totreatment planning from consultation to surgery.Excellent color illustrations and intraoral imagescompliment the text. The indications for specificradiographic surveys in the anterior mandible aredescribed, and high-quality radiographic imagesclarify the treatment planning process. The pearlin this chapter is in the author’s contingency plan-ning for the implant sites at the treatment plan-ning stage. A description of the fabrication of thesurgical guide and its importance in ensuring thepredictable placement of the implants concludesthe chapter.

Following the discussion on treatment plan-ning, Dr. R. Mericske-Stern (in Chapter 10) re-views the clinical considerations in overdenturetherapy. Topics considered are fixed prosthesesversus overdentures, number of implants, splintedor unsplinted implants, resilient or rigid reten-tion, and overdenture success and implant sur-vival. Once again, we see the recommendationthat treatment outcomes be measured by patient-related factors rather than just implant and pros-thetic survival.

Dr. Ignace Naert addresses the influence ofattachment systems (bars, balls, and magnets) onclinical outcomes by reviewing a clinical trial inChapter 11. He concludes that the splinting ofimplants with a bar is not a prerequisite for the

long-term survival or prognosis of implants in themandible.

Loading strategies for mandibular implantoverdentures are discussed through review of aclinical overdenture study involving 4 implant sys-tems with different healing times prior to loading.The authors’(Drs. A. G. T. Payne, A. Tawse-Smith,W. M. Thomson, and W. J. Duncan) descriptionof bone quality and quantity is different than thatproposed by Lekholm and Zarb,1 but is not a sourceof confusion for the reader. The results of thisclinical study can be used as a guide in selectinga loading strategy for unsplinted ball-retainedoverdentures. High-quality color intraoral imagesand radiographs illustrate the different anchorsystems and clarify the treatment of the intagliodenture surface for loading.

Drs. P. Boudrias and A. Chehade present astep-by-step overview of the procedures from ini-tial clinical assessment, through surgery, to ball-attachment activation in Chapter 13. The au-thors’ 49 clinical color/radiographic images are ofhigh quality and provide a concise and thoroughsummary. Although this chapter better servesthe novice, the clinical images clarify the loadingstrategy mentioned in the previous chapter. Theauthors’ surgical guide provides a lingual accessfor the surgical drill. It would be informative forthe authors to include either an explanation or aclinical view of a surgical guide restricting surgicaldrill access to one path of placement.

The final chapter provides a complete overviewof the text with a realistic appraisal of the currentoverdenture status, its future, and areas for con-tinued research. The author (Dr. G. E. Carlsson)suggests that although the trend for increasinguse of implant-retained overdentures will proba-bly continue, conventional complete dentures willremain a realistic and necessary alternative formany edentulous patients.

For both the student and the experienced clin-ician, this text offers a philosophy for successfultreatment of edentulism by utilizing a patient-centered approach and the two-implant mandibu-lar overdenture. It provides thorough evidence-based documentation in a quality bound softcover with heavy paper stock, excellent supportivetables, graphs, illustrations, radiographs, and in-traoral color images. The editors have done anexcellent job of directing the 23 contributingauthors to create a cohesive vision throughoutthe text, including the provision of a realistic

December 2004, Volume 13, Number 4 283

assessment of the current status of the implant-retained overdenture in clinical practice and sug-gestions for future research. The authors alsosuggest a patient-based treatment approach. Thiswill be a valuable text for all students or clini-cians wishing to incorporate the two-implant over-denture into their treatment philosophy. It pro-vides evidence-based information to guide boththe care-provider and the patient in making treat-ment decisions.

Richard A. Williamson, DDS, MSAssistant Professor, Department of Prosthodontics,

The University of Iowa College of Dentistry, Iowa

City, IA

References

1. Lekholm U, Zarb GA: Patient selection and preparation.In Branemark PI, Zarb GA, Albrektsson T (eds): Tissue-Integrated Prosthesis. Chicago, IL, Quintessence Publish-ing Co., 1985, pp 199-208

Implants inClinicalDentistry

Editors: Richard M. Palmer, Brian J. Smith, Leslie C.

Howe, Paul J. Palmer. Martin Dunitz Publishers, Ltd.,

Thieme, New York, NY, 2002: ISBN 1-85317-805-5,

256 pages; 600 photos (mostly color, 50 b/w); price $89.95,

hardcover

This book was written to provide comprehen-sive information on the prosthetic and surgicalphases of implant dentistry, and is intended foruse by general practitioners, prosthodontists, andoral surgeons alike. This book is divided into 5parts. Part 1 reviews the success criteria of os-seointegration and discusses patient factors suchas age, untreated dental disease, severe mucosallesions, and smoking. Other factors, such as im-plant biomechanics, including implant length, di-

ameter, shape, and surface characteristics, arealso discussed. Additionally, submerged and non-submerged protocols, different loading conditions,and guidelines for choosing various implant sys-tems are covered in Part 1.

Part 2 is divided into 5 chapters covering treat-ment planning of single anterior and posteriorteeth, fixed bridge planning, and diagnosis andtreatment planning for implant dentures. Thissection provides an overall view of treatment plan-ning. It discusses general esthetic principles withemphasis on comprehensive clinical data collec-tion, including clinical examination, radiographicscreening, study casts, diagnostic set up, and basictreatment sequencing. The authors discuss singleimplant tooth planning in the anterior region indetail. They emphasize that in order to achieveideal esthetic results, the complete evaluation ofthe status of the adjacent teeth, the ridge andsoft tissue profile, planning and precise implantplacement, sympathetic surgical handling of thesoft tissue, and a high standard of prosthetics areall needed. The authors suggest the use of differ-ent implant options for the single tooth implantand, as an alternative, the use of wide diameterimplants whenever necessary.

The remaining chapters discuss the treatmentplanning for multiple implants. They cover theplanning of the numbers of implants to be placed,as well as their distribution. Also presented isa treatise on choosing between fixed bridges ormultiple single units with a presentation of dif-ferent prosthodontic options for implant retaineddentures. These chapters are well written, and thediagrams and photographs are of high quality. Theinformation is up-to-date and would be extremelybeneficial for all members of the implant team, butespecially those who are involved in the restorativephase.

Part 3 is divided into 6 chapters, which dis-cuss the basic factors in implant surgery, in-cluding heat generation during implant place-ment, primary stability of implants, implant po-sition, preoperative care, anesthesia and analge-sia, flap design and soft tissue handling, surgi-cal placement of the single tooth implant in theanterior maxillae, implant placement for fixedbridgework, and immediate and early replace-ment implants. Additional emphasis is placedon treatment planning and interdisciplinary ap-proach, in order to achieve the best esthetic andfunctional results.

284 Book Reviews

Part 4 of the text is divided into 3 chap-ters covering single tooth implant prosthodon-tics, fixed bridge prosthodontics, and implantdenture prosthodontics. These chapters discussvarious types of implant abutments, their advan-tages and disadvantages, along with indicationsand contraindications for each. Again discussedare impressions of the implant platform, as well asabutment level impressions, shade selection, anda review of laboratory techniques. A comparison ofscrew-retained versus cement-retained prostheseswith their accompanying advantages and disad-vantages is well presented. This section of thebook provides excellent, comprehensive, easy-to-read coverage of restorative implant dentistry andcan be a great benefit to both the general dentistand the prosthodontist.

Part 5, the last section of the text, dis-cusses both surgical and prosthetic complications,their cause, and how to manage such complica-tions. A detailed list of routine hygiene mainte-nance requirements for single tooth restorations,fixed bridges, and removable prostheses is alsopresented.

This book is a valuable resource for clini-cians and educators. The authors present a greatamount of timely information on aspects of bothprosthetic and surgical implant dentistry. A va-riety of information is presented in a clear, con-cise, and easy-to-read manner. The authors ofthis text deserve a good deal of credit for pro-ducing such a well-written and comprehensivetext.

Raed Ajlouni, DDSAssistant Professor, Department of General Dentistry,

Baylor College of Dentistry, Dallas, TX

ImplantDentistry:From Failureto Success

Editors: Ira D. Zinner, Francis Panno, Stanley Small,

Lloyd Landa. Quintessence Publishing Co., Inc., Carol

Stream, IL, 2004: ISBN 0-86715-438-1, 212 pages; 365

illustrations (mostly in color); price $124, hardcover

Eleven contributing authors and four editorsproduced this text, which includes 13 chaptersand a forward by Dr. George Zarb. The purposeof the text, as suggested by the title, is a reviewof the use of implant-supported prostheses in themanagement of failed conventional and implant-supported oral rehabilitations. Special emphasis isplaced on understanding the causes of failures andmethods for avoiding potential problems and com-plications. The editors and authors continuouslystress the need for a team approach to prosthet-ically direct implant therapy. Many complex fail-ures with subsequent rehabilitations are discussedand illustrated throughout the text, which appearsto be written for highly experienced clinicians andspecialists.

The book begins with an overview of the au-thors’concepts of managing patients with failed orfailing prostheses. The next chapter, “Diagnosisand Treatment Planning for Implant-SupportedFixed Prosthodontics,’’ is a standard overview oftreatment planning for implant dentistry. Com-puterized tomography (CT) is briefly mentioned,but a comprehensive review of the role of CTscans with radiographic templates in planningcomplex rehabilitations is conspicuously absent.Also, screw-retained restorations are strongly ad-vocated in this chapter and throughout the text de-spite the current trend toward the use of cement-retained implant-supported fixed restorations.1

The third chapter, “Presurgical Prosthodon-tics,’’ describes the authors’ approach to the useof surgical templates, surgical index copings, andprovisional prostheses. All procedures are compre-hensively illustrated in a series of 10 cases. Thetext then reviews problems that can occur before,during, and after implant surgery, along with so-lutions to these problems. Seven cases illustrat-ing the authors’ use of metal-reinforced, implant-supported provisional restorations are illustratedin the subsequent chapter, “Second-Stage Screw-Retained Provisional Prostheses.’’

The chapter titled “Occlusal Considerationsto Prevent Prosthesis and Component Com-plications’’ contains common-sense advice formanaging the occlusion with implant-supportedprostheses, such as the avoidance of cantilevers.Nevertheless, the authors advocate the routine useof screw-retained restorations with acrylic resin

December 2004, Volume 13, Number 4 285

occlusal surfaces for “shock absorption.’’ In thisreviewer’s experience, occlusal stability can be lostrapidly with acrylic resin occlusal surfaces becauseof accelerated wear, especially with complete-arch rehabilitations. Also, the concept of usingacrylic resin as a “shock absorber’’ was based onconjecture in the 1980s, during the profession’searly clinical experiences with implant-supportedprostheses; the validity of this assumption hasnot been proven scientifically. The authors alsosuggest that the occlusal scheme should directocclusal contacts over the centers of the prostheticplatforms of the implants. Developing centric oc-clusal contacts over the center of the implants isdifficult with screw-retained prostheses because ofthe location of the screw-access holes.1 The sectionon screw mechanics and occlusion in this chapterimplies that tightening “torque force’’ for a screwis synonymous with the term “preload.’’ Preload isthe initial load in tension on the screw producinga clamping force that results from the tensionbetween the threads of the screw and the screwhead.2 The preload that is developed is the resultof the applied torque and is usually proportionalto the tightening torque, commonly described inN cm. It should be noted that these two terms arerelated, but are not exactly synonymous.2

The next two chapters provide an excellentanalysis of maxillary sinus grafting. Surgical pro-cedures and prosthetic management are reviewed,along with the anatomy and pathophysiology ofthe sinuses. Together, these two chapters providea comprehensive and concise overview of the topic.

The text then proceeds to highlight the me-chanical aspects of fabricating implant-supportedprostheses with a chapter titled “Technical Con-siderations to Optimize Prosthetic Success.’’ Thischapter appears tailored to the dentist only, be-cause it is not sufficiently detailed to guide a dentallaboratory technician. The laboratory proceduresdescribed and illustrated relate to screw-retainedrestorations, and many of the laboratory proce-dures for developing screw retention appear un-necessarily complicated. The section on auxiliaryscrew devices is especially difficult to follow, andillustrations of the techniques described would behelpful to the reader.

The standard approach to verifying passive fitof a screw-retained prosthesis is described. The

problems of screw loosening and screw fracturesare addressed, along with other complicationsrelated to damage or mechanical failure of im-plant components. An entire chapter is devotedto various approaches for managing failures intotally edentulous patients treated with implant-supported prostheses. This chapter, “Salvaging aFailed Implant-Supported Fixed Prosthesis in theCompletely Edentulous Patient,’’is extremely wellwritten and illustrated. A very brief and unimpres-sive overview of esthetics follows. The final chapterof the text, “Legal Aspects of Implant Practice,’’ isan excellent review of the legal ramifications ofimplant dentistry, and should be of interest to alldentists.

This text is handsomely bound and printed onexcellent quality paper stock. All 365 illustrationsare of exceptional quality. The overall writingstyle is clear and concise, although at times theauthors do not use current terminology as definedin the 7th edition of “The Glossary of Prosthodon-tic Terms.’’ 3 For example, “centric occlusion’’ isused when the authors obviously imply “maximalintercuspal position,’’ and the term “appliance’’ isoften used as a synonym for “prosthesis.’’ Thistext does provide a wealth of information notcurrently available in a single source, based uponthe authors’ comprehensive knowledge and vastexperience. It would be a welcome addition tothe library of any dentist involved in the care ofpatients requiring complex rehabilitations withimplant-supported prostheses.

Steven M. Morgano, DMDProfessor of Restorative Sciences and Biomaterials,

Director, Division of Postdoctoral Prosthodontics,

Boston University School of Dental Medicine, Boston,

MA

References

1. Hebel KS, Gajjar RC: Cement-retained versus screw-retained implant restorations: Achieving optimal occlu-sion and esthetics in implant dentistry. J Prosthet Dent1997;77:28-35

2. Alkan I, Sertgoz A, Ekici B: Influence of occlusal forceson stress distribution in preloaded dental implant screws.J Prosthet Dent 2004;91:319-325

3. Van Blarcom CW, Campbell SD, Carr AB, et al: The glossaryof prosthodontic terms. J Prosthet Dent 1999;81:48-110