A 20-year split-mouth comparative study of two screw-shaped titanium implant systems.

PURPOSE: To prospectively assess marginal bone loss and implant survival with Astra Tech (Dentsply Sirona, Charlotte, NC, USA) (group A) and Brånemark (Nobel Biocare, Zurich, Switzerland) (group B) implants in a split-mouth study conducted over a 20-year follow-up period. MATERIALS AND METHODS: A total of 95 implants (n = 50, group A and n = 45, group B) were randomly placed in the left or right side of the maxilla or mandible in 18 patients. Clinical and radiographic examinations were performed, and results were reported at 5, 10, 15 and 20 years after insertion of the prosthesis. RESULTS: Ten patients were followed up for 20 years (n = 26 implants, group A and n = 25 implants, group B). No implant loss or prosthetic failures were observed. After 20 years of follow-up, no significant differences in marginal bone loss were found between both implant groups (P = 0.25). The proportion of marginal bone loss ≥ 0.5 mm was not significantly different between implant types (P > 0.05), and no statistically significant relationships were found between marginal bone loss and time (P ≥ 0.05). More specifically, there was no significant difference in marginal bone level between year 20 and baseline in group A (P = 0.70), whereas a difference of 0.5 to 1.0 mm was found in group B (P = 0.15). CONCLUSIONS: After 20 years of follow-up, marginal bone loss around screw-shaped titanium implants was clinically insignificant. Furthermore, no significant differences in survival and marginal bone loss were found between group A and B implants over the follow-up period.

Diagnosis, avoidance and management of complications of implant-based treatments.

"If terms be incorrect, then statements do not accord with facts". (Confucius) "Words form the thread on which we string our experiences". (Aldous Huxley) Semantics is a term coined by Michel Bréal (1832 to 1915) a Jewish German-French linguist referring to the Greek semantikos (= meaning) in his 1897 book, "Essai de sémantique". He was a very gifted man: for example, he was the one who suggested to Pierre de Coubertin to include the marathon in the Olympic Games and who also, with the help of a Francophile American dental practitioner, Thomas William Evans, created the "Doctorat d'Université", finally allowing American students to pursue their doctorate at a French university.

Brain plasticity and cortical correlates of osseoperception revealed by punctate mechanical stimulation of osseointegrated oral implants during fMRI.

PURPOSE: Our aim was to unveil the cortical neural correlates of osseoperception, i.e. the tactile sensation perceived when loading a bone-anchored implant, by taking oral implants as a model. This was performed in a cross-sectional observational study with 9 volunteering patients and 10 age-matched controls. For each patient, functional magnetic resonance imaging (fRMI) recordings were made during punctate mechanical stimulation of either teeth or osseointegrated implants in the maxillary incisor area. MATERIALS AND METHODS: During fMRI recordings, 1 Hz punctate tactile stimuli were applied either on a maxillary left central incisor, canine tooth or central incisor implant. A block design paradigm was used to stimulate, in 9 patients, maxillary left central incisor implants (I21-p) and maxillary left canines (T23-p). In 10 control subjects, maxillary left central incisors and canines (T21-c, T23-c) were stimulated. Random effect group analyses were performed for each stimulated site, and differences in cortical activity elicited when loading teeth or implants were examined using ANOVA. RESULTS: As a group, patients activated somatosensory area S2 bilaterally for both I21 and T23, while controls activated S1 and S2 bilaterally for T21 and T23. At an individual level, S1 was activated by 4/9 implants, mainly on the ipsilateral side. The stimulated implants activated a larger bilateral cortical network outside the somatosensory areas: in parietal, frontal and insular lobes, the main clusters being located in the inferior frontal gyri. Stimulation of T23 in patients resulted in an activation pattern intermediate between that of the implants and that of natural teeth. CONCLUSION: This study demonstrates that punctate mechanical stimulation of oral implants activates both primary and secondary cortical somatosensory areas. It also suggests that brain plasticity occurs when extracted teeth are replaced by endosseous implants. This cortical activation may represent the underlying mechanism of osseoperception.

Working Group on Treatment Options for the Maintenance of Marginal Bone Around Endosseous Oral Implants, Stockholm, Sweden, 8 and 9 September 2011. Methodology.

PURPOSE: To reach through intense interactions among a group of renowned experts a better view of the treatment options available for marginal bone maintenance and eventual inflammation and/or loss around oral implants. The working group was intended to generate guidelines useful for th clinical community at large. FORMAT: Two days of interactive presentations and discussions on the basis of review papers delivered beforehand by the participants. Each of the participants was asked to focus on a particular aspect of the global theme--maintenance of marginal bone around oral implants and treatment options while keeping a global view for further discussion. From the prepared reviews only the conclusions were presented at the meeting as an introduction for the discussions. The reviews were distributed among all participants beforehand and, if needed, the other participants could draw the attention of the author on missing aspects and references prior to the meeting. A general consensus was formulated. The consensus was amended during the two days of the meeting until a unanimous opinion was reached. Minority statements could be considered. The review papers were not required to be systematic reviews (time and means were lacking) but they were to be valuable critical analyses considering the internationally recognised expertise of the authors.

Perceptual changes in the peri-implant soft tissues assessed by directional cutaneous kinaesthesia and graphaesthesia: a prospective study.

BACKGROUND: The innervation of skin and oral mucosa plays a major physiological role in exteroception. This innervation is also clinically relevant as sensory changes occur after neurosurgical procedures. PURPOSE: The goal of this study was to compare the perception of mechanical stimuli applied to the buccal mucosa in the vicinity of osseointegrated oral implants with that in the controlateral dentate side. The role of the previously reported increased innervation in the peri-implant soft tissues in the oral sensorimotor function was thus examined. MATERIALS AND METHODS: Seventeen subjects with 20 implants were tested. Directional cutaneous kinaesthesia (DCK) and graphesthesia (G) were performed on the buccal side of the alveolar mucosa before and at planned intervals after implant placement. The observation was pursued until 6 months after the prosthetic rehabilitation. In each subject, the contralateral mucosa served as a control to the implant sites. Average percentages of correct responses in a four-choice task for DCK and a three-choice task for G were calculated. RESULTS: Despite an intersubject variation in both the DCK and G, high intraindividual correlations were found (p < .005). The implant sites showed a significant difference toward the control sites at the four interval test for both tests. For DCK and G, the average of correct responses decreased after abutment connection (i.e., after the implant uncovering surgery) to increase afterwards to reach a level close to, but still lower than, the control sites 3 to 6 months after the prosthetic rehabilitation. CONCLUSION: The DCK and G are simple but reliable sensory tests that can be easily applied in the oral region. This prospective study indicates that tooth loss reduces tactile function compared with implant-supported prostheses. The peri-implant soft tissues could be partially involved in the osseoperception function.

A split-mouth comparative study up to 16 years of two screw-shaped titanium implant systems.

INTRODUCTION: Many studies have dealt with the clinical outcome of oral implants, yet none applied a randomized split-mouth design for a long-term follow-up of similar implant systems. AIM: To evaluate two oral implant systems with different surface characteristics in a randomized split-mouth design and to radiologically analyse peri-implant bone level and density over an up to 16-year period. MATERIALS AND METHODS: The study comprised clinical and radiographic records of 18 partially edentulous patients treated with both implant types randomly placed in either left or right jaw sides. Outcome was evaluated over time. RESULTS: Clinical and radiographic parameters showed no significant differences over time for both systems. Ten years after implant placement, a significantly increasing peri-implant bone density was noted, while Periotest values were found to be significantly decreasing. Fifteen years after implant loading, mean bone loss was 0.02 mm (range -1.15 to 1.51; SD 0.45) for Astra Tech® implants (n=24) and 0.31 mm (range -0.98 to 2.31; SD 0.69) for Brånemark® implants (n=23). CONCLUSIONS: The study failed to demonstrate significant differences in the outcome of the peri-implant bone for two implant systems with different surface characteristics. The marginal bone level around oral implants changed <0.5 mm after 15 years of loading.

Bone healing after dental extractions in irradiated patients: a pilot study on a novel technique for volume assessment of healing tooth sockets.

The aim of this study was to evaluate longitudinally the bone-healing process by measuring volumetric changes of the extraction sockets in head and neck cancer patients undergoing radiotherapy after tooth extraction. A total group of 15 patients (nine males, six females) undergoing tooth extraction at the Department of Periodontology (University Hospital KULeuven) were enrolled after giving informed consent. In seven patients, teeth presenting a risk for complications and eventual radionecrosis were extracted prior to the radiotherapeutical procedure. Monitoring of bone healing was performed by evaluating the volumetric changes of the alveoli by cone beam CT scanning (CBCT) at extraction and after 3 and 6 months. In parallel, a similar longitudinal evaluation of extraction sites was done in a control group of eight patients. Within this pilot-study, a total of 15 healing extraction sockets were evaluated and followed up. There was a significant difference in volumetric fill up of extraction sockets in test group vs. control group at three (37.1 +/- 7.9%) vs. (54.6 +/- 4.0%) and 6 months (47.2 +/- 8.8%) vs. (70.0 +/- 7.3%), respectively. The present pilot study demonstrated the clinical usefulness of CBCT for evaluation of extraction socket healing. The study objectively demonstrates the delayed bone healing after tooth extraction in irradiated head and neck cancer patients. Considering the limitations of this pilot study, a potential effect of radiotherapy on further jaw bone healing after pre-therapeutic tooth extractions should be further explored.

GC-MS analysis of breath odor compounds in liver patients.

BACKGROUND: Liver diseases can cause a sweet, musty aroma of the breath, called fetor hepaticus. Even in a stage of cirrhosis, the disease can be asymptomatic for many years. Breath analysis might be helpful to detect occult liver pathology. STUDY OBJECTIVE: This study examined whether specific breath odor compounds can be found in liver patients, suffering from cirrhosis, which might be useful for diagnosis. MATERIALS AND METHODS: Fifty-two liver patients and 50 healthy volunteers were enrolled. Alveolar air was analyzed by gas chromatography-mass spectrometry. Using discriminant analysis a model for liver disease was built. RESULTS: Dimethyl sulfide, acetone, 2-butanone and 2-pentanone were increased in breath of liver patients, while indole and dimethyl selenide were decreased. Sensitivity and specificity of the model were respectively 100% and 70%. CONCLUSIONS: Fetor hepaticus is caused by dimethyl sulfide and to a lower extent by ketones in alveolar air. Breath analysis by GC-MS makes it possible to discriminate patients with breath malodor related to hepatic pathologies.

Bone formation following implantation of bone biomaterials into extraction sites.

BACKGROUND: Adequate bone volume is imperative for the osseointegration of endosseous implants, but postextraction resorption and remodeling may challenge implant placement. The use of bone biomaterials has been advocated to fill extraction sites and to enhance primary implant stability during osseointegration. The objective of the case series was to evaluate bone formation histologically and biomechanically in extraction sites following implantation of three commercially available bone biomaterials to compare their ability to allow guided bone regeneration. METHODS: Thirty-six periodontally involved teeth were extracted from eight healthy non-smoking subjects. At least two bone biomaterials, a synthetic sponge based on polylactic-polyglycolic acid technology (FIS), bovine porous bone mineral (BPBM), or a natural coral derivative physically and chemically transformed into a calcium carbonate ceramic (COR), and one non-grafted control were applied to the extraction sockets within each subject and were covered by an expanded polytetrafluoroethylene device. The devices were removed after 2 months, and trephine biopsies were obtained from each site 4 months later. At that time, endosseous implants were placed in 25 of the sites, and healing abutments were placed; measurements were taken 4 to 6 months later with an electronic mobility testing device. RESULTS: The percentage of residual biomaterial was 5.6% +/- 8.9% for FIS (P <0.001), 20.2% +/- 17.0% for BPBM (P <0.05), and 12.0% +/- 16.4% for COR (P <0.001). The amount of residual biomaterial after 6 months showed a significant relationship with the insertion torque measurements during the first third of implant insertion (P <0.05) and with values of the electronic mobility testing device at the abutment connection (P = 0.05). Histologically, new bone apposition was seen on BPBM particles. FIS sites showed similar ingrowth of blood vessels and osteocytes as empty controls. CONCLUSION: All sites revealed good primary stability at implant insertion and proper implant rigidity at abutment placement, indicating that early implant osseointegration was not influenced by the application of bone biomaterials used in this study.

Impact of local and systemic factors on the incidence of late oral implant loss.

BACKGROUND: This retrospective study was set to assess the influence of systemic and local bone and intra-oral factors on the occurrence of implant loss from abutment connection up to 2 years. MATERIALS AND METHODS: The files of 700 patients, have been collected randomly from the total patient group treated by means of endosseous Brånemark system implants (Nobel Biocare, Gothenburg, Sweden) at the Department of Periodontology of the University Hospital of the Catholic University of Leuven. The end point observation was evaluating the loss of the implants 2 years after abutment installation. The study involved all implants that did not encounter early loss and implants for which it was possible to evaluate its status 2 years after abutment surgery. Thus, data of 412 patients (240 females) provided with 1514 implants were analyzed. For each patient, the medical history was carefully checked. Data collection and analysis were mainly focused on endogenous factors such as hypertension, coagulation problems, osteoporosis, hypo- hyperthyroidism, chemotherapy, diabetes type I or II, Crohn's disease, some local factors [e.g. bone quality and quantity, implant (length, diameter, location), type of edentulism, PTV, radiotherapy], smoking habits, and breach of sterility during surgery. RESULTS: Radiotherapy, implant (diameter and location), and higher PTV at implant insertion and abutment connection, all affected significantly the implant loss. CONCLUSION: Implant location in the oral cavity and radiotherapy seem predominant to explain the occurrence of implant loss. On the other hand, smoking and systemic health factors do not seem to be prominent players in the etiology of late implant loss.

Bone augmentation with autologous periosteal cells and two different calcium phosphate scaffolds under an occlusive titanium barrier: an experimental study in rabbits.

BACKGROUND: This study used a tissue-engineering approach, which combined autologous periosteal cells with a scaffold material, to promote bone augmentation under an occlusive titanium barrier that was placed on the skull of rabbits. Because the cell-matrix interaction is of key importance in tissue engineering, two different calcium phosphate-based scaffolds were seeded with autologous periosteal cells. One scaffold contained hydroxyapatite, tricalcium phosphate, and collagen; the other scaffold was a beta-tricalcium phosphate structure. METHODS: The experiment involved 38 rabbits divided into five groups: the two different scaffolds with and without cells and a blood clot only. Prior to implantation, autologous periosteal cells were harvested from the tibia by stripping the periosteum. Cells were cultured, and 1 day before the implantation approximately 20 million cells were collected and seeded onto the scaffolds. Two preformed dome-shaped full titanium barriers were placed subperiosteally onto the frontal and parietal bones of each rabbit. Before placement of the barriers, the different scaffolds, seeded with or without cells, were put on top of the skull. As a negative control, autologous blood was injected into the barriers. Histologic evaluation and histomorphometric analysis were performed after 12 weeks of undisturbed bone growth. Measurements involved the amounts of newly formed tissue and of new bone distinguishing between trabecular bone and osteoid. RESULTS: No significant differences were found between the four treatment groups (scaffolds with or without cells). However, the amount of new bone tissue found underneath the titanium barriers with scaffolds was significantly higher (P <0.04) than with a blood clot only. CONCLUSION: A better understanding of the mode of action is required to optimize tissue-engineering procedures before entering clinical applications.

Speech adaptation after treatment of full edentulism through immediate-loaded implant protocols.

OBJECTIVES: The objective of the present study was to evaluate the influence of immediate loading of implants on speech adaptation. MATERIAL AND METHODS: Ten patients (mean age 54, 6 females) were examined before surgery and 1, 3, 6 and 12 months afterwards. Articulation analysis was done using objective DAT-recoded data evaluated by two groups of speech and language therapists and a computer software program. Besides, patient VAS-scores, myofunctional problems and hearing impairment were recorded and analysed. RESULTS: In the present study only one patient suffered from deteriorated speech after immediate loading. Other patients showed unaffected or improved articulation 3 to 6 months after surgery with a strident and interdental pronunciation mostly becoming addental. Furthermore, myofunctional problems occurred in one patient, other patients adapted to the new situation after three months. Hearing impairment did not influence speech pathology in this study. CONCLUSION: Immediate loading of oral implants does not seem to compromise the normal 3-6 months speech adaptation period. Whether such procedure presents advantages to the conventional 2-stage rehabilitation remains to be investigated.

Impact of local and systemic factors on the incidence of failures up to abutment connection with modified surface oral implants.

AIM: This study aimed to assess the influence of systemic and local bone and intra-oral factors on the occurrence of early TiUnite implant failures. MATERIAL AND METHODS: A total of 283 consecutive patients (187 females; mean age 56.2), who received a total of 720 TiUnite implants, at the Department of Periodontology of the University Hospital of the Catholic University of Leuven, were prospectively followed. The following aspects were particularly assessed: hypertension, cardiac problems, gastric problems, osteoporosis, hypo- or hyperthyroid, hypercholesterolaemia, asthma, diabetes types I or II, Crohn's disease, rheumatoid arthritis, chemotherapy, hysterectomy and intake of medication (antidepressants, steroids, hormone replacement), radiotherapy of the concerned area, breach of sterility during surgery, implant parameters, bone (quality, quantity, dehiscence or perforation), type of edentulism, antibiotics prescription, fenestration of the implant in the sinus/nasal cavity, immediate implant placement, apical lesion detection and insertion torque. RESULTS AND CONCLUSION: A global failure rate of 1.9% was recorded. Owing to the very few failures, no definitive conclusion concerning statistical significance can be achieved. However, a tendency for more failures was noticed for apical lesions, vicinity with natural dentition, smoking, hormone replacement, gastric problems, Crohn's disease, diabetes I and radical hysterectomy.

Asepsis during periodontal surgery involving oral implants and the usefulness of peri-operative antibiotics: a prospective, randomized, controlled clinical trial.

OBJECTIVES: This randomized clinical trial compares the usefulness of pre- and post-operative antibiotics while strict asepsis was followed during periodontal surgery. MATERIAL AND METHODS: Two groups of 40 consecutive patients each with fully or partially edentulous jaws were enrolled. Antibiotics group (GrAB(+)): 23 men, mean age 60, 128 implants, received oral amoxicillin 1 g, 1 h pre-operatively and 2 g for 2 days post-operatively. Non-antibiotics group (GrAB(-)): 20 men, mean age 57, 119 implants, received no antibiotics. Bacterial samples were taken from the peri-oral skin before and at the end of surgery. In 12 patients in each group, samples were also taken from the nares. A VAS questionnaire evaluated symptoms of infection/inflammation by both the patient and the periodontologist at suture removal. RESULTS: There were no significant differences between both groups, neither for the clinical parameters nor for the microbiota. Staphylococcus aureus was detected in the nares of one patient only. The patients' subjective perception of post-operative discomfort was significantly smaller in the group receiving antibiotics. Three patients lost one or two implants. CONCLUSIONS: Antibiotics do not provide significant advantages concerning post-operative infections in case of proper asepsis. It also does not reduce peri-oral microbial contamination. It does on the other hand reduce post-operative discomfort.