- Email: [email protected]
Evolution of implant dentistry
and tooth function. These conditions, however, are also true for the use of CO2 snow and Endo-Ice. Conclusions.—LDF was the most promising of the techniques for assessing pulpal health and approached the status of a gold standard test. It is objective, is not painful, produces a readable computerized record that can be saved for future comparison, and can directly assess the presence or absence of blood flow in the dental pulp. These features make it the most attractive option for clinical practice.
Clinical Significance.—LDF may prove to be the best choice when pulp sensibility tests are expected to be unreliable, particularly after traumatic dental injuries. Other tests have their
uses as well. Having a better understanding of the pulpal health status may avoid being limited to a ‘‘wait and see’’ policy, which can be accompanied by a higher incidence of complications. Knowing the strengths and weaknesses of the various techniques to determine pulpal health will guide the clinician in choosing the best approach for each individual patient.
Alghaithy RA, Qualtrough AJE: Pulp sensibility and vitality tests for diagnosing pulpal health in permanent teeth: A critical review. Int Endod J 50:135-142, 2017 Reprints available from RA Alghaithy, King Fahad Hosp, PO Box 55498, Jeddah 21534, Saudi Arabia; e-mail: [email protected]
Implants Evolution of implant dentistry Background.—Implant dentistry was once an experimental approach to replacing missing teeth but has become a predictable option used in daily practice. The long-term results are outstanding, with many studies reporting 10-year survival and success for 95% of the patients assessed. The history of implants, the current status of this approach to partial or full edentulousness, and remaining questions were reviewed. Historical Development.—Between 1965 and 1985, dentistry went from a basic understanding of the surgical guidelines for predictably achieving osseointegration to the development of implant systems that offered mainly two-piece titanium screw-type implants using a machined or rough titanium plasma-sprayed surface. Two teams emerged as the leaders in implant research and development: the Br anemark team in Sweden and the Schroeder International Team for Implantology in Switzerland. Although they agreed on the basic principles of implant surgery, they differed on healing modality and implant surface. The Br anemark team used titanium screw-type implants with a rather smooth machined surface, but the Schroeder team used titanium implants of varying shapes with a titanium plasma-sprayed surface, making it rough and microporous. Although the Swedish group worked solely in edentulous individuals, the Swiss team used implants in
both fully edentulous mandibles and in partially edentulous patients with shortened dental arches and single tooth gaps. Various materials were tested over this period, along with various shapes. Between 1985 and 2000 some major changes occurred in implantology. Partially edentulous patients were increasingly being served; today they account for the majority of all implant patients. In addition, the demand to replace lost teeth became altered from a goal of just function to the desire for an esthetically pleasing solution to the problem of tooth loss. The esthetically driven demand led to the development of bone augmentation techniques to overcome bone deficiencies in potential implant sites. Guided bone regeneration using barrier membranes and sinus floor elevation were developed to address insufficient bone situations. Surgical modifications in the 1990s improved the predictability of guided bone regeneration and reduced the risk for complications. The use of resorbable barrier membranes became more widespread, reducing the number of surgical interventions and rate of complications. Surgical techniques for sinus floor elevation were also developed. Through studies of osseointegration principles, bone apposition to titanium surfaces, and removal torque,
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implants were developed that had new titanium surfaces called microrough or moderately rough. These are now the surfaces of first choice. The concept of early loading also became a way to reduce the healing period for implants and increase their attractiveness to patients. The improved microrough implant surfaces were instrumental in this step forward. Immediate implant placement was also introduced and has been debated over the years since. Between 2000 and 2010, efforts were made to fine-tune implant therapy with the goal of optimizing the primary and secondary objectives of this approach. The primary objectives are to achieve successful treatment outcomes based on functional, esthetic, and phonetic criteria and to have a low risk of complications during healing and follow-up. The secondary objectives are to have the fewest possible number of surgical interventions, to have patients experience the least pain and morbidity during healing, to maintain short healing periods, to have a short overall treatment time, and to achieve an effective result for the patient. Significant progress was achieved over this decade toward these goals. In particular, the esthetics of implant therapy was improved through a better understanding of correct three-dimensional implant positioning and improved manufacturing of titanium implants. The latter was helped along by the use of platform switching, which is designed to be more effective in maintaining periimplant bone levels in the crestal area. Post-extraction implant placement was also improved with a better understanding of the reasons for biologically driven ridge alterations and severe vertical bone resorption. This knowledge has further improved esthetic outcomes for implant patients, even long after the initial implant placement. Another advance made during this time was the use of bone fillers to improve the mechanical support of barrier membranes, provide biologic properties, and improve stability. Three-dimensional cone-beam computed tomography offered the advantages of better image quality and lower radiation exposure compared to previous dental computed tomography. It also led to the development of digital implant dentistry, where computers could aid in obtaining scans for digital impressions, providing designs for the implants, and fabricating the implants. In addition, the resonance frequency analysis technique provided clinicians with an objective diagnostic tool to evaluate implant stability at any stage in the life of the implant. Current Status.—Modern surface-modified implants have an implant survival rate of more than 95%, with under 5% developing a purulent infection or peri-implantitis. The
274
Dental Abstracts
development of peri-implantitis remains a controversial topic, with no clear indication on what needs to be done to address it. Improved esthetic outcomes and the practicality of digitally designed abutments have given clinicians a clear indication that cementable options are preferable. However, cement remnants have been implicated as possible sources for peri-implantitis. Today both early loading and conventional delayed loading have a role in implant therapy. Patients have comparable healing with the two approaches, but their cases should be managed based on which is best for their individual circumstances. Computer-guided impressions are done using an intraoral scanner, which can eliminate a source of error. In addition, computer-guided design software and milling processes are proving cost-beneficial. Patients today are often older adults who have medical risk factors, functional impairments, and the possibility of becoming frail and dependent. These must be considered in therapeutic planning to minimize morbidity for these patients. Ceramic (zirconia) implants are becoming more popular. These are based on zirconium dioxide implants and have undergone successful preclinical testing. The current data for these implants indicate that their performance is comparable to that of pure titanium implants with modern microrough surfaces first reported in the early 1990s. Remaining Questions.—Besides the controversy surrounding peri-implantitis, the cause of crestal bone loss remains unknown. Such loss appears to be inevitable during the first year of loading, but some patients show more bone loss than others and some have a continuous bone loss that remains unexplained. The result can be poor esthetics, discomfort, and implant failure. The long-term performance of newer materials such as the zirconia implants remains to be seen. In addition, the value of platelet-rich plasma, platelet-rich fibrin, and other variants is currently lacking in clinical support but should be assessed over the coming years. Peri-implant mucosal recession develops in many cases. Although it does not usually significantly influence longterm maintenance of the implant, it can alter esthetic outcome and lower patient satisfaction. Treatment possibilities are currently limited. Finally, the best clinician to provide implant therapy is a hotly debated subject. Oral and maxillofacial surgeons and periodontal surgeons have dominated the field in the
United States, but in Europe, general practitioners have performed implant therapy for years. As more general dentists get involved in this growing field, there is concern about the training available, the timing of this training, and the necessary skills that should accompany any foray into implant treatment.
Clinical Significance.—Many changes have come over the years in the field of implantology. As we move forward, some of the challenges and questions will be resolved, but it
is likely that others will arise. The welfare of the patient must remain the primary motivation for providing implant therapy; that much is sure.
Buser D, Sennerby L, De Bruyn H: Modern implant dentistry based on osseointegration: 50 years of progress, current trends and open questions. Periodontology 2000 73:7-21, 2017 Reprints not available
Mini implant retained overdentures Background.—Implant-retained overdentures offer a way to rehabilitate patients who are edentulous that provides function and esthetics as well as patient satisfaction. The use of two standard implants to support an overdenture is the recommended first choice, but mini implants offer several advantages that make them a good choice for some patients. For example, they have a reduced diameter, require a less complex surgical technique, permit implant placement in areas with low bone thickness, and are associated with reduced postoperative morbidity compared to standard implants. The viability of using mini implants to retain overdentures was evaluated through a systematic review of the literature.
Of 1576 mini implants in which survival was measured, 121 failed, for a survival rate of 92.32%. The failure rates were higher for maxillary arch sites than for mandibular arch sites (31.71% versus 4.89%).
Methods.—The PubMed/MEDLINE, Embase, and Cochrane Library databases were searched for studies published before September 2016 that dealt with the use of mini implants with complete overdentures for the prosthodontic rehabilitation of edentulous patients. Twenty-four studies were identified, representing 1273 patients (mean age 65.93 years) who received 2494 mini implants and 386 standard implants to retain overdentures. Mean follow-up was 2.48 years, with a range from 1 to 7 years.
Overdenture prostheses held by mini implants had significantly better retention, stability, chewing, speaking, comfort, esthetics, patient satisfaction, and social life or quality of life scores than overdentures supported by conventional implants in most studies. Maximum bite force (MBF) was high with the mini implants, with values similar to those achieved with conventional implants.
Results.—The use of 4 mini dental implants was the most common approach for rehabilitation, especially in the mandibular arch. The retention system ball was the system of choice for all but 2 studies, which used prefabricated bar retention systems with splinted mini implants. Generally, flapless surgery was the surgical technique selected for mini implant placement.
Marginal bone loss values were less than 1.5 mm in all but 1 study, which reported more than 1.5 mm in the maxillary arch. Splinted with the prefabricated bar was associated with a lower marginal bone loss (0.92 mm) than the ball system was (1.43 mm), but the difference did not reach statistical significance. In the maxilla, palatal coverage was considered an important factor in preventing vertical bone loss, but did not impact horizontal bone loss.
Overdenture survival was reported for 244 overdentures retained by mini implants. Twenty-three fractured, for a survival rate of 90.58%. Fracture was more likely in areas of metal housing. Repair was possible in most cases of fracture. Conclusions.—Mini implants are proving to be a valuable option for patients who either do not want or cannot have standard implants placed. Mini implant supported overdentures offer survival rates comparable to
Volume 62
Issue 5
2017
275
Clinical Significance.—LDF may prove to be the best choice when pulp sensibility tests are expected to be unreliable, particularly after traumatic dental injuries. Other tests have their
uses as well. Having a better understanding of the pulpal health status may avoid being limited to a ‘‘wait and see’’ policy, which can be accompanied by a higher incidence of complications. Knowing the strengths and weaknesses of the various techniques to determine pulpal health will guide the clinician in choosing the best approach for each individual patient.
Alghaithy RA, Qualtrough AJE: Pulp sensibility and vitality tests for diagnosing pulpal health in permanent teeth: A critical review. Int Endod J 50:135-142, 2017 Reprints available from RA Alghaithy, King Fahad Hosp, PO Box 55498, Jeddah 21534, Saudi Arabia; e-mail: [email protected]
Implants Evolution of implant dentistry Background.—Implant dentistry was once an experimental approach to replacing missing teeth but has become a predictable option used in daily practice. The long-term results are outstanding, with many studies reporting 10-year survival and success for 95% of the patients assessed. The history of implants, the current status of this approach to partial or full edentulousness, and remaining questions were reviewed. Historical Development.—Between 1965 and 1985, dentistry went from a basic understanding of the surgical guidelines for predictably achieving osseointegration to the development of implant systems that offered mainly two-piece titanium screw-type implants using a machined or rough titanium plasma-sprayed surface. Two teams emerged as the leaders in implant research and development: the Br anemark team in Sweden and the Schroeder International Team for Implantology in Switzerland. Although they agreed on the basic principles of implant surgery, they differed on healing modality and implant surface. The Br anemark team used titanium screw-type implants with a rather smooth machined surface, but the Schroeder team used titanium implants of varying shapes with a titanium plasma-sprayed surface, making it rough and microporous. Although the Swedish group worked solely in edentulous individuals, the Swiss team used implants in
both fully edentulous mandibles and in partially edentulous patients with shortened dental arches and single tooth gaps. Various materials were tested over this period, along with various shapes. Between 1985 and 2000 some major changes occurred in implantology. Partially edentulous patients were increasingly being served; today they account for the majority of all implant patients. In addition, the demand to replace lost teeth became altered from a goal of just function to the desire for an esthetically pleasing solution to the problem of tooth loss. The esthetically driven demand led to the development of bone augmentation techniques to overcome bone deficiencies in potential implant sites. Guided bone regeneration using barrier membranes and sinus floor elevation were developed to address insufficient bone situations. Surgical modifications in the 1990s improved the predictability of guided bone regeneration and reduced the risk for complications. The use of resorbable barrier membranes became more widespread, reducing the number of surgical interventions and rate of complications. Surgical techniques for sinus floor elevation were also developed. Through studies of osseointegration principles, bone apposition to titanium surfaces, and removal torque,
Volume 62
Issue 5
2017
273
implants were developed that had new titanium surfaces called microrough or moderately rough. These are now the surfaces of first choice. The concept of early loading also became a way to reduce the healing period for implants and increase their attractiveness to patients. The improved microrough implant surfaces were instrumental in this step forward. Immediate implant placement was also introduced and has been debated over the years since. Between 2000 and 2010, efforts were made to fine-tune implant therapy with the goal of optimizing the primary and secondary objectives of this approach. The primary objectives are to achieve successful treatment outcomes based on functional, esthetic, and phonetic criteria and to have a low risk of complications during healing and follow-up. The secondary objectives are to have the fewest possible number of surgical interventions, to have patients experience the least pain and morbidity during healing, to maintain short healing periods, to have a short overall treatment time, and to achieve an effective result for the patient. Significant progress was achieved over this decade toward these goals. In particular, the esthetics of implant therapy was improved through a better understanding of correct three-dimensional implant positioning and improved manufacturing of titanium implants. The latter was helped along by the use of platform switching, which is designed to be more effective in maintaining periimplant bone levels in the crestal area. Post-extraction implant placement was also improved with a better understanding of the reasons for biologically driven ridge alterations and severe vertical bone resorption. This knowledge has further improved esthetic outcomes for implant patients, even long after the initial implant placement. Another advance made during this time was the use of bone fillers to improve the mechanical support of barrier membranes, provide biologic properties, and improve stability. Three-dimensional cone-beam computed tomography offered the advantages of better image quality and lower radiation exposure compared to previous dental computed tomography. It also led to the development of digital implant dentistry, where computers could aid in obtaining scans for digital impressions, providing designs for the implants, and fabricating the implants. In addition, the resonance frequency analysis technique provided clinicians with an objective diagnostic tool to evaluate implant stability at any stage in the life of the implant. Current Status.—Modern surface-modified implants have an implant survival rate of more than 95%, with under 5% developing a purulent infection or peri-implantitis. The
274
Dental Abstracts
development of peri-implantitis remains a controversial topic, with no clear indication on what needs to be done to address it. Improved esthetic outcomes and the practicality of digitally designed abutments have given clinicians a clear indication that cementable options are preferable. However, cement remnants have been implicated as possible sources for peri-implantitis. Today both early loading and conventional delayed loading have a role in implant therapy. Patients have comparable healing with the two approaches, but their cases should be managed based on which is best for their individual circumstances. Computer-guided impressions are done using an intraoral scanner, which can eliminate a source of error. In addition, computer-guided design software and milling processes are proving cost-beneficial. Patients today are often older adults who have medical risk factors, functional impairments, and the possibility of becoming frail and dependent. These must be considered in therapeutic planning to minimize morbidity for these patients. Ceramic (zirconia) implants are becoming more popular. These are based on zirconium dioxide implants and have undergone successful preclinical testing. The current data for these implants indicate that their performance is comparable to that of pure titanium implants with modern microrough surfaces first reported in the early 1990s. Remaining Questions.—Besides the controversy surrounding peri-implantitis, the cause of crestal bone loss remains unknown. Such loss appears to be inevitable during the first year of loading, but some patients show more bone loss than others and some have a continuous bone loss that remains unexplained. The result can be poor esthetics, discomfort, and implant failure. The long-term performance of newer materials such as the zirconia implants remains to be seen. In addition, the value of platelet-rich plasma, platelet-rich fibrin, and other variants is currently lacking in clinical support but should be assessed over the coming years. Peri-implant mucosal recession develops in many cases. Although it does not usually significantly influence longterm maintenance of the implant, it can alter esthetic outcome and lower patient satisfaction. Treatment possibilities are currently limited. Finally, the best clinician to provide implant therapy is a hotly debated subject. Oral and maxillofacial surgeons and periodontal surgeons have dominated the field in the
United States, but in Europe, general practitioners have performed implant therapy for years. As more general dentists get involved in this growing field, there is concern about the training available, the timing of this training, and the necessary skills that should accompany any foray into implant treatment.
Clinical Significance.—Many changes have come over the years in the field of implantology. As we move forward, some of the challenges and questions will be resolved, but it
is likely that others will arise. The welfare of the patient must remain the primary motivation for providing implant therapy; that much is sure.
Buser D, Sennerby L, De Bruyn H: Modern implant dentistry based on osseointegration: 50 years of progress, current trends and open questions. Periodontology 2000 73:7-21, 2017 Reprints not available
Mini implant retained overdentures Background.—Implant-retained overdentures offer a way to rehabilitate patients who are edentulous that provides function and esthetics as well as patient satisfaction. The use of two standard implants to support an overdenture is the recommended first choice, but mini implants offer several advantages that make them a good choice for some patients. For example, they have a reduced diameter, require a less complex surgical technique, permit implant placement in areas with low bone thickness, and are associated with reduced postoperative morbidity compared to standard implants. The viability of using mini implants to retain overdentures was evaluated through a systematic review of the literature.
Of 1576 mini implants in which survival was measured, 121 failed, for a survival rate of 92.32%. The failure rates were higher for maxillary arch sites than for mandibular arch sites (31.71% versus 4.89%).
Methods.—The PubMed/MEDLINE, Embase, and Cochrane Library databases were searched for studies published before September 2016 that dealt with the use of mini implants with complete overdentures for the prosthodontic rehabilitation of edentulous patients. Twenty-four studies were identified, representing 1273 patients (mean age 65.93 years) who received 2494 mini implants and 386 standard implants to retain overdentures. Mean follow-up was 2.48 years, with a range from 1 to 7 years.
Overdenture prostheses held by mini implants had significantly better retention, stability, chewing, speaking, comfort, esthetics, patient satisfaction, and social life or quality of life scores than overdentures supported by conventional implants in most studies. Maximum bite force (MBF) was high with the mini implants, with values similar to those achieved with conventional implants.
Results.—The use of 4 mini dental implants was the most common approach for rehabilitation, especially in the mandibular arch. The retention system ball was the system of choice for all but 2 studies, which used prefabricated bar retention systems with splinted mini implants. Generally, flapless surgery was the surgical technique selected for mini implant placement.
Marginal bone loss values were less than 1.5 mm in all but 1 study, which reported more than 1.5 mm in the maxillary arch. Splinted with the prefabricated bar was associated with a lower marginal bone loss (0.92 mm) than the ball system was (1.43 mm), but the difference did not reach statistical significance. In the maxilla, palatal coverage was considered an important factor in preventing vertical bone loss, but did not impact horizontal bone loss.
Overdenture survival was reported for 244 overdentures retained by mini implants. Twenty-three fractured, for a survival rate of 90.58%. Fracture was more likely in areas of metal housing. Repair was possible in most cases of fracture. Conclusions.—Mini implants are proving to be a valuable option for patients who either do not want or cannot have standard implants placed. Mini implant supported overdentures offer survival rates comparable to
Volume 62
Issue 5
2017
275