Diabetes mellitus is one of the world’s major chronic health problems and one whose prevalence is increasing dramatically worldwide. Diabetes is a condition characterized by deficiency of intracellular glucose. This shortage can either be caused by severe primary insulin deficiency in the blood or failure of glucose to enter the cells. The former pattern is termed insulin-dependent type 1 diabetes mellitus while the latter is noninsulin-dependent type 2 diabetes mellitus. The most common form of diabetes is type 2 diabetes (over 90% of people with diabetes have type 2). These two main types of diabetes are distinct and different diseases in themselves.
High concentrations of blood glucose will eventually result in secondary complications associated with diabetes. These complications are microvascular disease, susceptibility for infection, and delayed wound healing. Such complications may also affect the healing potential following endosseous implant treatment. For this reason, patients with diabetes were not considered suitable for implant treatment when the treatment was introduced in the 1970s. However, over the past decades, diabetes has not been regarded as an absolute contraindication for implant surgery but rather a relative contraindication related to the stability of the diabetic’s blood sugar level. Therefore, nowadays, many diabetic patients have been treated with dental implants. The purposes of the present study were to investigate how many diabetic patients and types of cases are treated with dental implants in our clinic and to assess the outcome of such treatment.
Material and Methods
Medical records were examined in patients treated for partial or total edentulism with implant supported bridges at the Department of Oral and Maxillofacial Surgery, Central Hospital in Västerås during the years 1991 to 2000. From these records, patients with diabetes before treatment were identified, and these records were further studied. For the diabetic patients, the following variables were registered from the patient records: age, gender, type of diabetes, treated jaw, degree of edentulism, bone graft, implant survival, and oral and dental complications.
As per to our routines, surgery was considered only for patients with a history of well-controlled plasma glucose levels; otherwise, the patients’ physicians were contacted to make corrective procedures before implant surgery was initiated. All patients were treated based on the Brånemark method. 1–6 Oral antibiotics were administered to all patients during a 1-week period after surgery, starting 1 hour before surgery.
The diabetic patients were contacted and offered to visit the clinic for registration of tissue conditions. The following variables were registered at the patient checkup: periimplant inflammation (measured as inflammation or no inflammation), bleeding on probing (measured as bleeding or no bleeding), and radiographic bone loss (measured as number of threads). Furthermore, the patients’ opinion about the outcome of the treatment was registered as either satisfactory or unsatisfactory.
Records from 782 patients who had received dental implant treatment were identified. Of these 782 patients, 25 (3.2%) were diabetic before installation of dental implants. The median age of the diabetic patients was 63 years, ranging from 47 to 79 years. The frequency of insulin-dependent diabetes (type 1) and noninsulin-dependent diabetes (type 2) was 36% and 64%, respectively. Among the diabetic patients, 20% were smokers.
Characteristics of the diabetic patients are summarized in Table 1. In total, 136 implants were installed in diabetic patients. Treatment of totally edentulous mandibles dominated the treatment (50%); partial edentulism with two or more missing teeth was the second most common cause of treatment (29%). In three patients, a combination of total and partial edentulism in different jaws were treated (21%). Diabetic patients with single tooth loss were not treated during the study period.
The majority of the implants (127) were inserted using a two-stage surgical procedure while the remaining implants (9) were loaded immediately after placement. The healing period ranged between 0 and 8 months, Which in the maxilla always extended to 6 months. Bone grafting was required in 3 of 136 implant sites in the diabetic patients. All of the patients were followed through the uncovering and final restoration and were given a checkup 1 year after surgery. Fig. 1 depicts type of treatment, number of installed fixtures, and number of lost fixtures in each group.
Upon uncovering, 131 of the 136 implants had osseointegrated, which gives an implant survival rate of 96.3% during the healing period. Of the five failed implants, three occurred in one patient and one in each of two patients. Of the latter two patients, one had a second implant placed successfully. None of these patients were smokers. Of the five surgical failures, two were located posterior to the maxilla, two at the anterior maxilla, and one in the anterior mandible. None of the three grafted sites failed. Of the 131 implants (28 bridges) that were followed through final restoration up to the final check-up 1 year after surgery, three additional failures were identified. These failures occurred in the same patient who already had lost three implants at the time of second-stage surgery. This condition resulted in removal of the bridge and increased the total failure rate to 5.9% at 1-year postsurgery.
One patient developed an oroantral fistula after fixture operation, which was surgically corrected. Thirteen patients appeared for a checkup and registration of tissue conditions (1–9 years) after implant installation. Neither periimplant inflammation nor bleeding was noted. One implant exhibited radiographic vertical bone loss corresponding to the distance between two thread prominences vertically. All patients were satisfied with the treatment, except for one who lost several implants.
We found that 3.2% of our implant patients were diabetics, where 36% were diagnosed as type 1 (insulin-requiring diabetes) and 64% as type 2 (adult-onset diabetes). In Sweden, diabetes is found in approximately 2.5% of the population, of whom 85 to 90% fall into the type 2 category, and over 50% of those are over 65 years old. 7 In our study, 56% of the type 2 diabetics were over 65 years of age, which is in accord with the national figure in Sweden. A large portion of adult tooth loss is caused by periodontal disease, a disorder that is more prevalent and more severe in diabetic patients. Furthermore, the severity of the disease tends to increase with the duration of diabetes. 8–11 Because type 1 has an earlier onset than type 2 diabetes, one can assume that tooth loss is more frequent in patients with the former form of diabetes. Such an assumption could account for the high incidence of type 1 diabetics in our material.
Several investigations on wound healing around endosseous implants in experimental diabetes in rats have been reported. 12–15 In 1998, Takeshita et al 12 found that uncontrolled diabetes could hinder bone formation around titanium implants in rats. Quantitative evaluation indicated that a control group showed a significantly higher percent of bone contact and thickness of surrounding bone and area as compared with a diabetes group. Nevins et al 13 and Goodman and Hori 14 reported similar findings. Wound failure, particularly infection, is encountered in varying degrees in 5 to 10% of diabetic patients who undergo surgery, and as a group, diabetic patients experience more infection in clean wounds than nondiabetics. 15 We found no such high incidence in our records, however. Only one of our patients postoperatively developed oroantral fistula, which was surgically corrected.
The clinical success rate of osseointegrated implants in the healthy patient has been studied extensively. Long-term success has been demonstrated in both complete and partially edentulous patients. 1–6 Although the replacement of teeth with dental implants has become a highly effective modality, their predictability relies on successful osseointegration during the healing period. 16
In our study, 5 of the 136 implants installed in 25 patients were lost after first-stage surgery, yielding a success rate of 96.3% during the healing period. These losses occurred in three patients: all were nonsmokers and had, according to their own statements in interviews, acceptable glycemic control at the time of surgery. This figure is slightly higher than that observed in the Balshi and Wolfinger study, 17 where the survival rate was 94.3% in 34 diabetic patients treated with 227 Brånemark implants. Our figure is also higher than the one reported by Olson et al, 18 where a survival rate of slightly over 90% was noted in 89 male type 2 diabetics with 178 implants.
Furthermore, of the 131 implants followed through final restoration and final checkup 1 year after surgery, three additional failures were identified, resulting in an overall success rate of 94.1%. This percentage is somewhat higher than Olson et al’s 18 88.0% but lower than Balshi and Wolfinger’s 17 99.1%. Mericske-Stern and Zarb 19 reported an overall 5-year success rate exceeding 90% in 23 diabetic patients, and Fiorellini et al 20 noted an overall success rate of 85.6% after 6.5 years in 40 diabetics. In two other studies, Smith et al 21 reported no implant failures in five diabetics, while Kapur et al 22 also reported no failures over a 2-year period in 52 patients with diabetes restored with two mandibular implants and one overdenture. Our findings indicate that excellent results can be obtained when Brånemark implants are placed in well-controlled diabetic patients.
Periodontal parameters were used for monitoring long-term periimplant tissue. Controversy exists as to the specificity and sensitivity of such parameters when applied to implants. Favorable healthy tissue conditions were found in all patients who showed up for an oral examination 1 to 9 years after insertion of the implants. This finding suggests that diabetic patients are highly motivated regarding their oral health.
In this study, only health history and personal interviews were used to determine the diabetic status of the patients. Recent experience from one of our bone grafted diabetic patients, in which postoperative loss of part of a bone graft led us to investigate the blood glucose level retrospectively by contacting his physician, revealed that high levels of blood glucose had been present though the patient had reported a well-controlled blood sugar level. Some patients may report that their diabetes is under good control because of fears that they will be excluded from treatment. Rather than relying only on the patients’ history, an objective way to estimate plasma glucose control is to estimate glycosylated hemoglobin (HbA1c) before surgery. In most laboratories, the normal HbA1c level is about 6%. In poorly controlled diabetics, the level ranges from 9 to 12%. HbA1c is not a specific test for diagnosing diabetes; however, elevated levels indicate the need for some corrective procedures. Measuring the HbA1c level as a routine for all diabetic patients could be of value in identifying patients under conditions in which further investigation and correction should be performed before implant surgery.
Today, diabetic patients are being successfully treated for all types of edentulism, including bone-grafting treatment. Diabetics that undergo dental implant treatment do not encounter a higher failure rate than the normal population if the patients’ plasma glucose level is normal or close to normal as assessed by personal interviews.
The authors wish to thank the clinic staff for participating in the collection of data and treatment of the patients.
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The authors claim no financial interest in any company or any of the products mentioned in this article.
Abstract Translations [German, Spanish, Portuguese, Japanese]
AUTOR(EN): Payam Farzad, DDS*, Lars Andersson, DDS, PhD**, Jan Nyberg, DDS***. *Assistenzarzt, Abteilung für Gesichts- und Kieferchirurgie, Zentralklinik, Västerås, Schweden. ** Professor, Abteilung für Gesichts- und Kieferchirurgie, Zahnärztliche Fakultät, Universität von Kuwait, Kuwait. *** Fachärztlicher Berater, Abteilung für Gesichts- und Kieferchirurgie, Zentralklinik, Västerås, Schweden. Schriftverkehr: Payam Farzad, DDS, Department of Oral and Maxillofacial Surgery, Central Hospital (Abteilung für Gesichts- und Kieferchirurgie, Zentralklinik), 72189 Västerås, Schweden. Telefon: +46 21 175440, Fax: +46 21 175430. eMail:firstname.lastname@example.org
ZUSSAMENFASSUNG: Die vorliegende Studie diente dazu, erstens die Anzahl der in unserer Klinik unter Einsatz von Zahnimplantaten behandelten Patienten mit Diabetes und die entsprechenden Fallvarianten festzustellen, und zweitens eine Bewertung der Behandlungsergebnisse durchzuführen. Hierzu wurden die Krankenakten von insgesamt 782 Patienten, deren teilweiser oder vollständiger Zahnverlust mittels der Brånemark-Methode über implantatgestützte Prothesen behandelt wurde, herangezogen. 25 Patienten (3,2 %) waren bereits vor der Implantatbehandlung mit insgesamt 136 Implantaten in diabetischer Behandlung. Diese wurden unter Berücksichtigung der Angaben zu Alter, Geschlecht, Diabetes-Typ, behandeltem Kiefer, Ausmaß der Zahnlosigkeit, Knochentransplantat, Überlebensdauer der Implantate, Entzündungsneigung im an das Implantat angelagerten Gewebe, Auftreten von Blutungen bei Sondierung und mittels Röntgenuntersuchungen ermitteltem Knochengewebsverlust einer Untersuchung unterzogen. Zusätzlich wurden die betroffenen Patienten zu ihrer Meinung bezüglich des Behandlungsergebnisses befragt. Die Erfolgsrate der Implantierung lag bei gesamt 96,3 % im Verlauf des Heilungsprozesses und sank bei Betrachtung ein Jahr nach erfolgtem Eingriff auf 94,1 %. Eine der Brücken musste wieder entfernt werden, und auch andere Komplikationen traten selten auf. Nur einer der Patienten zeigte sich mit dem Behandlungsergebnis unzufrieden.
Nach dem heutigen Stand der medizinischen Behandlungsmöglichkeiten können diabetische Patienten bei allen Formen des Zahnverlustes erfolgreich behandelt werden; dies schließt auch die Knochentransplantierung nicht aus. Die Implantierungsbehandlung bei Patienten mit Diabetes ist im Vergleich zu Patienten ohne Diabetes keinem höheren Versagensrisiko ausgesetzt. Voraussetzung für eine erfolgreiche Behandlung bildet allerdings eine normale oder annähernd normale Einstellung des Blutzuckerspiegels, so die Schlussfolgerung aus Befragung der Patienten.
SCHLÜSSELWÖRTER: Zahnimplantate, Diabetes, Knochengewebsintegration, Kiefer- und Gesichtschirurgie, chirurgische Eingriffe im Vorfeld der Prothesenanpassung
AUTOR(ES): Payam Farzad, DDS*, Lars Andersson, DDS, PhD**, Jan Nyberg, DDS***. *Residente, Departamento de Cirugía Oral y Maxilofacial, Hospital Central, Västerås, Suecia. ** Profesor, Cirugía Oral y Maxilofacial, Facultad de Odontología, Universidad de Kuwait, Kuwait. ***Consultor, Departamento de Cirugía Oral y Maxilofacial, Hospital Central, Västerås, Suecia. Correspondencia a: Payam Farzad, DDS, Department of Oral & Maxillofacial Surgery, Central Hospital, 721 89 Västerås, Sweden. Teléfono: +46 21 175440. Fax: +46 21 175430. Correo electrónico:email@example.com
ABSTRACTO: El propósito de este estudio tuvo dos aspectos: (a) investigar cuántos pacientes diabéticos y tipos de casos son tratados con implantes dentales en nuestra clínica y (b) evaluar el resultado de dichos tratamientos. Se examinaron los registros médicos de 782 pacientes en pacientes tratados con el método Brånemark de edentulismo parcial o total con puentes apoyados en implantes. De estos registros, se identificaron 25 pacientes (un 3,2%) con diabetes antes del tratamiento con implantes (136 implantes) y estudiaron con respecto a edad, sexo, tipo de diabetes, mandíbula tratada, grado de edentulismo, injerto de hueso, supervivencia del implante, inflamación periimplante, pérdida de sangre al tocarlo y pérdida radiográfica del hueso. Además, se incluyeron las opiniones de los pacientes sobre el resultado de los tratamientos. La tasa de éxito de los implantes fue del 96,3% durante el período de curación y 94,1% un año después de la cirugía. De todos los 38 puentes, se perdió uno. Ocurrieron pocas complicaciones; y todos los pacientes, excepto uno, estuvieron satisfechos con el tratamiento.
Hoy, los pacientes diabéticos son tratados exitosamente por todos los tipos de edentulismo, incluyendo el tratamiento con injerto de hueso. Los diabéticos que reciben el tratamiento con implantes dentales no encuentran una tasa de falla más alta que la población normal, si el nivel de glucosa en el plasma del paciente es normal, o cercano al normal, según lo evaluaron las entrevistas personales.
PALABRAS CLAVES: implantes dentales, diabetes, oseointegración, cirugía maxilofacial, cirugía preprotética
AUTOR(ES): Payam Farzad, DDS*, Lars Andersson, DDS, PhD**, Jan Nyberg, DDS***. * Residente, Departamento de Cirurgia Maxilofacial e Oral, Hospital Central, Västerås, Suécia. ** Professor, Cirurgia Maxilofacial e Oral, Faculdade de Odontologia, Universidade do Kuwait, Kuwait. *** Consultor, Departamento de Cirurgia Maxilofacial e Oral, Hospital Central, Västerås, Suécia. Correspondências devem ser enviadas a: Payam Farzad, DDS, Departamento de Cirurgia Maxilofacial e Oral, Hospital Central, 72189 Västerås, Suécia. Telefone: +46 21 175440, Fax: +46 21 175430. e-mail:firstname.lastname@example.org
SINOPSE: este estudo tem finalidade dupla: (a) investigar quantos pacientes diabéticos e que tipos de casos são tratados com implantes dentários em nossa clínica e (b) analisar os resultados destes tratamentos. Foram analisados históricos médicos de 782 pacientes pelo Método Brânemark para edentulismo total ou parcial com pontes sustentadas por implantes. A partir destes relatórios, foram identificados 25 pacientes (3,2%) com diabetes antes do tratamento com implante (136 implantes), pacientes esses que foram estudados mais a fundo em questões de idade, sexo, tipo de diabetes, mandíbula tratada, grau de edentulismo, enxerto ósseo, sobrevivência do implante, inflamação do periimplante, sangramento na sondagem e perda óssea radiográfica. Além disto, foram registradas as opiniões dos pacientes a respeito dos resultados dos tratamentos. O grau de sucesso dos implantes foi de 96,3% durante o período de cicatrização e de 94,1% um ano após a cirurgia. Das 38 pontes, perdeu-se uma. Ocorreram poucas complicações e todos os pacientes, exceto um, demonstraram estar satisfeitos com o tratamento.
Atualmente, os pacientes diabéticos estão sendo tratados com sucesso para todos os tipos de edentulismo, inclusive tratamento de enxerto ósseo. Os diabéticos submetidos a tratamento de implante dentário não têm um grau de insucesso superior ao da população normal, caso o nível de glicose no plasma do diabético seja normal, ou próximo ao normal, conforme determinado por avaliação em entrevistas pessoais.
PALAVRAS-CHAVES: implantes dentários, diabetes, osseointegração, cirurgia maxilofacial, cirurgia pré-protética