Ligature-induced marginal inflammation around osseointegrated implants and ankylosed teeth: stereologic and histologic observations in cynomolgus monkeys (Macaca fascicularis)

The aim of the investigation was to provide quantitative and qualitative histologic data on marginal inflammation around osseointegrated implants. The significance of the lack of a periodontal ligament in the initial breakdown phase of supporting tissues in implants was examined by comparing stereologic and histologic manifestations of ligature-induced marginal inflammation around osseointegrated implants with those around ankylosed and normal control teeth in 8 cynomolgus monkeys (Macaca fascicularis). Clinical and radiographic findings have been reported elsewhere. The marginal connective tissue around ligated implants was infiltrated by a significantly increased total number of lymphocytes, plasma cells, and neutrophils compared to non-ligated implants and teeth. The total number of lymphocytes around ligated implants was significantly higher than around ligated ankylosed and normal control teeth. There were, however, no significant differences in the total number of plasma cells and neutrophils within the ligated group. Osteoclasts were exclusively observed around ligated implants and ankylosed teeth. Although variations in microbiota and susceptibility of different jaw positions to periodontal break-down may influence the results of the present study, the results seem to substantiate the theory that marginal inflammation around implants and ankylosed teeth may have more serious implications than does marginal inflammation around teeth with a periodontal ligament. Since presence of osteoclasts was not related to the absence of cervical cementum with inserting gingival fibers around ligated ankylosed teeth, the increased susceptibility of bone loss of implants is probably not caused by the absence of these tissue components. In contrast, the histologic observations seem to support that the increased susceptibility for bone loss around implants may be related to the absence of a periodontal ligament.     

The influence of periodontitis on the subgingival flora around implants in partially edentulous patients

The hypothesis that teeth act as reservoirs of micro-organisms for the colonization of oral implants has recently been stated several times. The present study aimed at examining, in partially edentulous patients with severe periodontitis, whether pockets around teeth and implants harbored a comparable micro-flora. In 6 patients (3 with refractory periodontitis and 3 with advanced chronic adult periodontitis), plaque samples were taken from a deep and shallow pocket around both teeth and implants for differential phase contrast microscopy and DNA probe analysis. The results showed important differences in the sub-gingival flora between the 2 disease groups, as well as between deep and shallow pockets, around both implants and teeth. On the other hand, when pockets around teeth and implants with equal depths were compared a striking similarity was observed in the microbial composition. These observations confirm the hypothesis that pockets around teeth act as a reservoir and highlight the importance of periodontal health when oral implants are planned.     

Current practice in the preoperative evaluation of patients undergoing major vascular surgery: a survey of cardiovascular anesthesiologists

Comparison was made of the masseter muscle reflexes evoked by tapping on osseointegrated single-tooth aluminum oxide implants, and on natural teeth in nine patients. Tapping on eight out of nine patients evoked an inhibitory masseter muscle reflex, whereas tapping on all of the natural teeth evoked an inhibitory reflex. The threshold for this reflex was clearly elevated in implants compared to natural teeth. The pathway for the impulses responsible for this reflex and the clinical implications of the elevated threshold are discussed.     

The influence of splinting procedures on the periodontal and peri-implant tissue damping characteristics. A longitudinal study with the Periotest device

The aim of the present study was to evaluate the capability of the Periotest device in detecting and monitoring functional changes in the periodontal as well as in the pari-implant damping characteristics. In the first part of this study, 107 teeth were splinted by means of 40 full acrylic fixed prostheses (AFP) and another 37 teeth were splinted by means of 14 ceramometallic fixed prostheses (C-MFP). The Periotest measurements of individual teeth were done the day the fixed prostheses were cemented temporary (PTV 1), and again after a mean observation period of 27.4 days (PTV 2). In the 2nd part, 78 osseointegrated two-stage implants were splinted by means of 23 full acrylic fixed prosthesis (AFP) and other 18 implants were left without it. Using the same abutment length, Periotest measurements were performed, at abutment connections and before installation of the final prosthesis. In a 3rd part, using both implants and teeth as abutments, 29 osseointegrated implants were connected with 25 abutment teeth by means of 7 AFP. The measurements were performed at the beginning of the prosthetic treatment and 2, 4 and 6 weeks later. After splinting teeth by means of AFP for the observation period, no statistically significant reduction in PTVs was found. When on the other hand, a C-MFP was used, PTV 2 showed a significant reduction. The PTVs at abutment connection went down after a period of time, during which some implants were interconnected by means of an AFP and others were not.(ABSTRACT TRUNCATED AT 250 WORDS)     

Are mu-opioid receptors involved in the control of endothelin-1 release from the pituitary gland in normal and dehydrated rats?

A stereognostic ability test was performed in 60 patients. Forty patients were rehabilitated by means of osseointegrated implants. One group consisted of 20 patients with fixed prostheses on implants in both the upper and lower jaws. The other 20 patients had a maxillary denture while in the mandible an overdenture was retained by means of two implants connected by a bar. They were compared to a group of 20 subjects (controls) with a non-restored natural dentition. For the stereognostic ability test, subjects had to recognise ten different test pieces by manipulating them with two antagonistic incisor teeth, avoiding any contact with other oral structures. Both response time and percentage accuracy of recognition were evaluated. The present findings indicated that subjects with an overdenture on implants did not score significantly different from those with an implant-supported fixed prosthesis. In contrast, subjects with teeth had a significantly better stereognostic ability. The percentage of correct responses was 52% for overdentures, 56% for fixed prostheses on implants and 75% for natural dentitions. From these results, it could be concluded that the stereognostic ability is impaired in subjects rehabilitated with osseointegrated implants by about one-third to one-quarter compared to subjects with natural teeth.     

Proteoglycan expression by human trabecular meshworks

The aim of the present study was to clinically assess the peri-implant and periodontal conditions 1 year after placement of oral implants (ITI Dental Implant System) in partially edentulous patients. In all, 127 patients (median age 50 years, range 17 to 79) were examined. They were all treated according to a concept of comprehensive dental care and had received fixed partial dentures (FPD). Significant differences were observed between implants and contralateral control teeth with respect to mean pocket probing depth (PPD) (2.55 mm at implants/2.02 mm at teeth), mean probing attachment level (PAL) (2.97 mm/2.53 mm) and bleeding on probing (BOP) (24%/12%) (Wilcoxon matched pairs sign rank test, P < or = 0.01), whereas mean modified plaque index (0.22/0.30), mean modified bleeding index (0.35/0.44) and mean recession (-0.42 mm/-0.51 mm) did not significantly differ between implants and teeth. Compared to control teeth, the width of keratinized mucosa at implants was significantly smaller at lingual, but not at buccal aspects. Regression analyses showed no significant association between the amount of keratinized mucosa and degree of inflammation. Recession, PPD and PAL were slightly influenced by the amount of keratinized mucosa indicating greater resistance to probing. Grouping the implants according to various lengths, type of fixation of the FPD or combination with natural teeth did not result in statistically significant different clinical parameters, whereas grouping according to different localization within the oral cavity did. For example, the mean PAL in 83 anterior implants was 2.52 mm, whereas 175 posterior implants had a mean PAL of 3.18 mm (Mann-Whitney U-test, P < or = 0.01). Regression analyses between the mean PAL for all implants in each patient and the mean PAL of the corresponding dentition revealed an r2 of 0.23 (P < or = 0.01). Using multiple regression analysis, the mean PAL of the implants showed to be significantly influenced by the combined factors "fullmouth" PII, "fullmouth" BOP and mean PAL of all teeth. The results of this study suggest that in partially edentulous patients the overall periodontal condition may influence the clinical condition around implants and thus reinforces the importance of periodontal treatment prior to and supportive periodontal therapy after the incorporation of osseointegrated oral implants.     

Teeth or implants: a 1990s dilemma

Using endosseous implants to replace missing teeth is a highly predictable process when the precepts defined by Br?nemark are followed. The question of whether or not to extract periodontally compromised teeth, however, remains controversial. This article presents a case report illustrating some of the concerns involved when treating a patient with a combination of natural teeth and implants, and proposes several compelling questions regarding the treatment decisions made in this case.     

The role of the surgeon in treating multiple organ failure

The treatment of young people with implants requires advanced planning and coordination of many different specialities within dentistry. Timing and sequence of therapy will often decide the success or failure of treatment. Congenital absence of many teeth (oligodontia) associated with or without syndromes poses not only functional but also psychosocial problems for young people. A case is presented in which orthodontist, restorative dentist, and periodontist evaluated and performed the necessary therapy for a young person who at the age of 9 was diagnosed with oligodontia/l. Nine implants were placed: 13 years, 8 months in the mandible and 15 years, 6 months in the maxilla. All implants were restored as single teeth. The patient was followed until age 20.     

Titanium screw implants for intermaxillary fixation of partially edentulous jaw

Establishment of the best possible relationship between upper and lower teeth is very important when treating jaw fractures and orthognathic deformities in partially edentulous patients. Many surgeons use arch bars and acrylic splints for intermaxillary fixation (IMF) to obtain the best occlusal relationships after the operation. In patients with sufficient teeth, IMF is not so difficult to realize. However, in partially edentulous patients, the available teeth may not be sufficient to apply arch bars or splints. This paper describes a system for IMF of a partially edentulous jaw. Screws made of medical-grade titanium are implanted into the alveolar ridges where two or more teeth are missing. Arch bars or acrylic splints secured on these implants and available teeth can be used safely for IMF. In vitro axial pull-out tests demonstrated that these implants can withstand the traction forces generated by elastics. Five partially edentulous patients, three with mandibular fractures and two with orthognathic problems, were treated with these implants. All patients healed without any complications and with the best possible occlusal relationships.     

Biomechanical considerations when combining tooth-supported and implant-supported prostheses

The force distribution of multiple tooth-supported and implant-supported prostheses is completely different. A direct correlation exists between the degree of flexion at the site of loading and the amount of force distribution to other members of the prosthesis. Micromovement produced by the periodontal fibers facilitates force distribution to all the root surfaces of the natural tooth abutments. The rigidity of the implant/abutment/prosthesis configuration concentrates the force at the crestal bone at the site of loading with limited distribution to the remaining implants. Differential mobility concentrates the force distribution to the bone support of the most rigid members of splinted natural teeth or to the implants when they are united with natural teeth in a combined prosthesis. Implants always support the natural teeth and never the other way around. Therefore a nonrigid attachment is recommended between a tooth-supported prosthesis and an implant-supported prosthesis when they are combined. However, when implants are interspersed with natural teeth in the same prosthesis, the restoration will be implant borne. This requires special force distribution analysis to prevent implant overload.     

Crevicular fluid enzymes from endosseous dental implants and natural teeth

Several neutrophil-derived enzymes that are present in the gingival crevicular fluid have been evaluated for use as risk markers for periodontal disease progression. However, very little information is available about the presence of these enzymes in peri-implant tissues. The purpose of this cross-sectional study was to compare levels of enzymes in gingival crevicular fluid between natural teeth and endosseous dental implants and between well-integrated and failing implants. Scores of plaque and gingivitis were recorded for 68 integrated implants, five failing implants, and 34 natural teeth in 12 completely edentulous and 18 partially edentulous subjects. Samples of gingival crevicular fluid were obtained from these sites using filter paper strips and were assayed for levels of neutral protease, neutrophil elastase, myeloperoxidase, and beta-glucuronidase. Neutral protease levels were higher (P = .066) at moderately to severely inflamed implant sites (Gingival Index of 2, 3) compared to mildly or noninflamed sites (Gingival Index of = 0, 1). Despite the small number (n = 5) of failing implants evaluated in this study, levels of neutrophil elastase, myeloperoxidase, and beta-glucuronidase were significantly higher (P < or = .001) around failing implants compared to successful implants. Neutral protease levels were also elevated around failing implants, but the difference was not statistically significant. Results of this study indicate that neutrophil elastase, myeloperoxidase, and beta-glucuronidase levels in GCF appear to be good candidates for study as risk markers of implant failure.     

Schizophrenia in twins

Attempts to save natural teeth have created numerous restorative, endodontic, and periodontal techniques it has always been considered the treatment of choice to save teeth whenever possible, and extreme efforts to save teeth are often considered because of the poor treatment alternatives for replacing them. Today osseointegration provides a predictable means of replacing teeth; therefore, retaining questionable teeth may not be as necessary as in the past. This article reviews situations in which the selective extraction of compromised natural teeth or even healthy natural teeth is considered because of alternative treatment options utilizing osseointegrated implants.     

Experimental peri-implantitis in consecutively placed, loaded root-form and plate-form implants in adult Macaca mulatta monkeys

This study is part of an on-going project describing the character of round- and plate-form implants placed in a primate model. In this paper 20 loaded plate-form and 23 root-form implants were connected to prostheses and experimental peri-implantitis was induced by ceasing scaling procedures and placing braided silk ligature around the implants. Twenty-four prostheses utilizing natural teeth were studied for comparison. Clinical measurements were carried out monthly for 6 months and radiographic measurements at 3 and 6 months post-ligature placement and cessation of scaling. Both root-form implants and plate-form implants showed a significant loss of crestal bone height at 3 and 6 months after ligature placement (P < .001 after 6 months). The difference in bone loss between plate- and root-form implants, however, was not significant.     

A new angle on restoring anterior teeth with root-form implants: clinical report

Root-form implants may be indicated for the replacement of missing anterior teeth. Occasionally fixtures are placed in a position inconsistent with proper tooth alignment. The new PreAngled Abutment (Dentsply/Implant Division, Encino, CA) addresses this problem and was used to successfully restore missing tooth numbers 7 and 8 for a patient that had two malpositioned implants.     

Four single-tooth implants as supernumerary premolars in the treatment of diastemas and microdontia: report of a case

The osseointegration concept involving single-tooth implants has become a valuable treatment component in many orthodontic situations. This case report illustrates the use of single-tooth implants as supernumerary teeth in the treatment of diastemas.     

Evaluation of consecutively placed unloaded root-form and plate-form implants in adult Macaca mulatta monkeys

The present paper describes 18 consecutively-treated non-human primates (Macaca mulatta) as part of a balanced block design study of 36 animals to examine osseointegration in root- and plate-form implants prepared by atraumatic preparation of bone. Clinical measurements around selected teeth and digital radiology were utilized to monitor periodontal disease and bone deposition around the unloaded implants. Once a month scaling procedures were utilized as a means of preventing further advance of periodontal disease. Results indicate that once-monthly regimen of scaling and root planing can prevent attachment loss of natural teeth and will not interfere with the healing of either type of implant; once-monthly scalings produce significant reduction in redness (P < .05) and reduced probing depths (P = .01). A second finding is that both root and blade implants show radiographic evidence of osseointegration in this primate model. The quantitative analysis demonstrates bone gain is not stabilized until 6 months after healing. The data may indicate that occlusal loading of mandibular implants at 3 months may be premature.     

Pigment cell research: what directions?

The purpose of this study was to compare the phenotypic distribution of resident gingival mononuclear inflammatory cells from tissues associated with peri-implantitis and periodontitis. Inflamed gingiva was obtained from six patients during surgical removal of failed dental implants. Similarly, inflamed gingiva around teeth was obtained from eight patients with moderate to advanced periodontitis. Monoclonal antibodies were used to identify membrane antigens from CD4+ T-lymphocytes, CD4+/CD8(+)-activated T-lymphocytes, tissue macrophages, CD20+ B-lymphocytes, and MHC class II (Ia) antigens. Gingival inflammation associated with both dental implants and natural teeth was characterized by substantial numbers of CD4+ T-lymphocytes, resident macrophages, and B-lymphocytes. In addition, there was an abundance of HLA class II-positive mononuclear cells throughout most specimens. These results suggest that the gingival mononuclear inflammatory response in peri-implantitis and periodontitis is similar and support the hypothesis that similar inflammatory mechanisms are associated with both conditions.     

The use of precision attachments in a lower full arch rehabilitation with osseointegrated implants--a clinical report

A technique for restoration of a case of Kennedy Class V edentulous span was described. This situation is a long edentulous span bounded anteriorly by a weak support and considered as one of the most difficult situations to restore. Two osseointegrated screw implants were inserted in the edentulous span. Together with remaining natural teeth supported a full arch restorations. Three precision attachments were included in the restoration to allow movement of the remaining teeth and to allow broken stresses at where the prosthesis extended along the corners of the mouth.     

A multidisciplinary approach to restoring posterior bite collapse

Treatment planning of posterior bite collapse cases with loss of vertical dimension can be complex. In cases where a patient's vertical dimension of occlusion has been lost, there often is drifting of posterior teeth, flaring of maxillary anterior teeth, and inadequate interarch space for a restoration. These factors are further complicated by the esthetic demands of the patient and the dentist and by the use of implants to replace missing teeth. This article presents a case report of a multidisciplinary treatment plan to achieve a functional and esthetic restoration.     

Tooth stabilization and splinting before and after periodontal therapy with fixed partial dentures

The design and use of fixed partial dentures as a definitive restoration to stabilize and splint teeth have been reviewed. The provisionalization of the splinted patient has been described as it is incorporated into the treatment plan of patients with a weakened periodontium. The current controversy of incorporating implants in the patient requiring splinting was discussed, and recommendations are made. Dentists are encouraged to explain all potential ramifications of splinting with fixed partial dentures, including cost, frequency of office visits, and potential alterations or remakes of the prosthesis should physiologic demands surpass the capabilities of the remaining teeth.