Immediate and flapless implant insertion and provisionalization using autogenous bone grafts in the esthetic zone: 5-year results.

OBJECTIVES: As the 2-year results for immediately inserted and provisionalized implants have been reported, it remained an open issue, whether the initially high success rates and the esthetic outcome remain stable for longer observation periods. Therefore, this prospective study examines the 5-year hard and soft tissue changes at implants placed in the anterior maxilla. MATERIAL AND METHODS: Meanwhile, 37 microthreaded implants were placed in 21 patients into extraction sockets with and without facial bone deficiencies by a flapless approach. Facial gaps and bony defects were grafted with autogenous bone chips. The implants were immediately provisionalized. The primary outcome parameters were the interproximal marginal bone level and the thickness of the facial bony wall. Implant success and Pink Esthetic Score (PES) were considered as secondary outcome parameters. RESULTS: Two patients with four implants withdrew from the study (dropouts), and the remaining 33 implants were still in function at a follow-up period of 68 months. Marginal bone height averaged 0.04 mm coronal to the implant shoulder. The thickness of the facial bony lamellae increased significantly between pre-op examination and 1-year follow-up (p = .002) and thereafter remained stable. Within 5 years of follow-up, 24 of 33 implants were clinically stable, free of signs and symptoms, and showed bone loss less than 1 mm. The mean PES ratings improved slightly from 10.7 pre-operatively to 11.7 at the last follow-up (p = .02). CONCLUSIONS: Interproximal marginal bone levels, survival rates, and esthetic results remain stable at the 5-year follow-up in implants used in an immediate insertion, reconstruction, and provisionalization concept. Facial marginal bone levels decreased slightly; however, this reduction did not affect the PES so far.

Third Molar Complications in the Elderly-A Matched-Pairs Analysis.

PURPOSE: The aim of this study was to evaluate the perioperative morbidity of third molar (3M) removal in elderly patients in an attempt to estimate the long-term future burden of 3M-related morbidity resulting from the postponement of 3M surgery to old age. MATERIALS AND METHODS: The study design was a retrospective matched-pair analysis comparing patients at least 65 years old (group A) with a control group of 15- to 20-year-old patients (group B). Age group was the predictor variable in this study. Outcome variables were general health status as defined by the modified Charlson score (MCS) and the American Society of Anesthesiologists (ASA) score, general surgical risks from antithrombotic or antiresorptive medication, and specific local surgical risks and complications. RESULTS: Patients in group A showed substantially more comorbidities as reflected in significantly higher MCS and ASA scores (P < .001). Older patients more frequently used antithrombotic agents (P < .001), had higher rates of ankylosis (P < .001) and nerve proximity (P < .001), and showed significantly more in intra- and postoperative complications (P < .001), thus resulting in longer operations and a substantially longer hospital stay (P < .001). CONCLUSION: Within the limits of a non-epidemiologic approach, this study showed a substantially greater burden of morbidity and substantially worse outcome of 3M surgery in older adults compared with young adults. For the medical risks of an aging population, the present data suggest a veritable burst of 3M-associated morbidity when surgery is shifted to late adulthood.

What is the best position for palatal implants? A CBCT study on bone volume in the growing maxilla.

OBJECTIVE: The objectives of the present study are the following: (a) to investigate limitations (bone height, proximity to nasopalatine nerve and roots) in juvenile patients, (b) to review the recommended site for surgical insertion (level of the maxillary first premolars), and (c) to reassess the rationale behind the manufacturer's age limitation (12 years). PATIENTS AND METHODS: Cone beam CT images of 100 patients aged 10 to 20 years were analyzed. Vertical bone heights were measured in the median plane as well as 3- and 6-mm paramedian along the prospective axis of insertion, at the level of the first premolars (level 0), 3 mm anterior (level 1) and 3 mm posterior (level 2). The Mann-Whitney U test was used to compare bone heights between gender groups. RESULTS: The risk of damage to the nasopalatine nerve is highest in the median region on level 1 (46 %). The risk was lowest in the midsagittal region on level 0 (recommended insertion site; 3 %) and level 2 (0 %), as well as paramedian on levels 0 and 2. The risk of damaging roots was irrelevant for median insertion at all levels; the only critical region was 6-mm paramedian on level 1. CONCLUSIONS: The recommendation of surgical insertion at the level of the maxillary first premolars is still justified, but a slightly more posterior implant position might improve safety. We found no relevant growth-related changes in the vertical bone heights in the median palatal area. Thus, our data do not support the strict 12-year age restriction for palatal implants.

Immediately provisionalized OsseoSpeed(™) Profile implants inserted into extraction sockets: 3-year results.

OBJECTIVES: A sloped shoulder might improve the congruence between extraction socket and dental implant and may add to a better circumferential support of the peri-implant structures. Therefore, this study evaluates the 3-year clinical outcome (survival and success rates, marginal bone levels, and Pink Esthetic Score (PES)) of immediately inserted and provisionalized OsseoSpeed(™) Profile implants in the anterior maxilla. MATERIAL AND METHODS: Twenty-one implants were inserted in 16 patients. All implants were immediately placed into extraction sites with and without facial bone deficiencies. A flapless procedure was utilized, and the implants were provisionalized immediately. Facial gaps were grafted with autogenous bone chips from the mandibular ramus. Implant survival and success, the interproximal bone levels, the thickness of the facial bony wall, and the PES were evaluated. RESULTS: After a mean follow-up period of 43 months, 19 implants were still in function. One patient with 1 implant did not follow the study protocol (dropout) and 1 implant was lost at 10 weeks. Interproximal marginal bone levels measured -0.2 ± 0.4 mm (range, -1.0-0.4 mm) apical to the implant shoulder. The mean PES ratings were 11.9 ± 1.4 (range, 8-14) at the final examination. CONCLUSIONS: Clinical and radiographic results provide evidence that sloped implants can preserve the marginal bone circumferentially and are able to maintain soft tissue esthetics when inserted and provisionalized immediately, even in the presence of facial bony wall defects.

Clinical parameter of odontoma with special emphasis on treatment of impacted teeth-a retrospective multicentre study and literature review.

OBJECTIVES: Odontoma-separated into complex (CxOD) and compound (CpOD) subtypes-represents the most frequent odontogenic malformation. Retention of permanent teeth is a common symptom. Therefore, in a series of odontomas, an analysis of the management of retained teeth was conducted. MATERIALS AND METHODS: In a retrospective multicenter study of two University Medical Centers and one private praxis in Germany, demographic and clinical data regarding odontomas from 01/2000-03/2015 were obtained. In particular, the influence of operative therapy on the dentition and on the treatment of impacted teeth was analyzed. RESULTS: Forty-five patients with 15 CxOD and 30 CpOD were included. Initial symptoms were delayed eruption of permanent teeth (n = 11), pain (n = 4), and swellings (n = 2); 28 cases were discovered by incidence, all of them via panoramic radiographs. The mandible/maxilla ratio was about 1:0.55 (29/16). Thirty-five out of 45 odontomas were in close proximity of at least one tooth (n = 16 at molars). A total of 14 teeth were extracted (CxOD: n = 5; CpOD: n = 9). Extractions had to be conducted more often in older patients (mean age 39.8 vs. 25.6 years). Of the non-extracted teeth, 8 teeth were displaced and retained. Of those, 4 teeth were aligned in the dental arch via orthodontic help and 2 teeth erupted spontaneously after operation during the follow-up period. In all cases, no relapse was seen. CONCLUSION: Odontomas can cause displacement as well as malformation and resorption of the adjacent teeth. CLINICAL RELEVANCE: Mostly, removal of odontomas is conducted. Extirpation of odontoma can allow for normal tooth eruption, often rendering extractions avoidable. Orthodontic alignment, though sometimes challenging, is a reasonable therapeutic option. These findings underline the value of the panoramic radiograph in preventive dentistry in younger patients.

Maintenance of marginal bone support and soft tissue esthetics at immediately provisionalized OsseoSpeed implants placed into extraction sites: 2-year results.

BACKGROUND: Placement of implants into extraction sockets targets the maintenance of peri-implant hard and soft tissue structures and the support of a natural and esthetic contour. The main advantages of immediate implant insertion in comparison with delayed implant placement protocols are as follows: a reduced treatment time, less number of sessions, and, thus, the less invasive procedure. This study examines the clinical performance (survival rate, marginal bone levels and Pink Esthetic Score [PES]) of OsseoSpeed implants placed into extraction sockets with immediate provisionalization in the anterior maxilla after a follow-up of at least 12 months. METHODS: Twenty patients received a total number of 37 OsseoSpeed implants which were immediately inserted into extraction sockets with or without facial bone deficiencies of various dimensions. A flapless procedure was applied, and the implants were immediately provisionalized with temporary crowns without occlusal contacts. Facial gaps between implant surface and facial bone or the previous contour of the alveolar process were grafted with autogenous bone chips. Implants in diameters 3.5, 4.0, 4.5, and 5.0 with lengths of 11-17 mm were used in the study. During the course of the study, interproximal marginal bone levels, the thickness of the facial bony wall, implant success rate according to the criteria established by Buser, and the PES were assessed per implant. RESULTS: One patient with three implants did not continue the study after prosthesis delivery, the remaining 34 implants were still in function at the final follow-up (survival rate: 100%). The mean follow-up period was 27 months (range, 12-40 months). Marginal bone height at the level of the implant shoulder averaged -0.1 ± 0.55 mm (range, -1.25 to 1.47 mm) at the final follow-up. The mean PES ratings were 11.3 ± 1.8 (range, 6-14) at the final follow-up. In 78% of the patients, the PES was preserved or even improved. CONCLUSIONS: Success rates, marginal bone levels, and esthetic results suggest proof of principle for the preservation of marginal bone height at immediately placed and provisionalized OsseoSpeed implants after a follow-up of at least 12 months. Even implant sites with facial bony deficiencies can be successfully treated with a favorable esthetic outcome using the immediate implant insertion, immediate reconstruction, and immediate provisionalization technique.

Oral squamous cell carcinoma in the vicinity of dental implants.

OBJECTIVES: The study at hand presents a cohort of patients treated for carcinomas in the vicinity of dental implants for identification of potential risk factors. MATERIALS AND METHODS: The retrospective analysis covers patients treated for peri-implant carcinoma at our department between 1995 and 2011. An additional literature search focused likewise on peri-implant carcinomas. Obtained articles were screened for relevant risk factors and discussed in relation to our patient cohort. RESULTS: Fifteen patients were treated for peri-implant carcinoma. Six reported ongoing alcohol/tobacco consumption. Nine had a previously reported carcinoma of whom six had received radiotherapy after surgery. Time from implant placement until carcinoma diagnosis was 53.4 months on average. The literature search revealed 25 patients with peri-implant carcinoma and one with a sarcoma. Eight patients reported alcohol/tobacco consumption. Most patients exhibited risk factors for possible malignant transformation: previous carcinoma (n = 12), lichen (n = 4), irradiation (n = 3), and leukoplakia (n = 3). The average time until diagnosis was 51.6 months. CONCLUSIONS: Smoking, alcohol consumption, and the history of previous carcinoma characterize patients at risk for a peri-implant carcinoma. A balanced gender ratio might point at a higher risk for woman and additional risk factors promoting carcinogenesis apart from tobacco and alcohol consumption, a novel finding that has to be proven by larger patient counts. CLINICAL RELEVANCE: The incidence of carcinomas next to dental implants is low but may attain clinical relevance with raising implant figures worldwide. Patients at risk potentially profit from individualized recall intervals and careful evaluation.

ΔNp63 expression in four carcinoma cell lines and the effect on radioresistance--a siRNA knockdown model.

OBJECTIVES: This study investigated the expression of ΔNp63α in carcinoma cell lines of the upper aerodigestive tract and their potential influence on radioresistance using a small interfering RNA (siRNA) knockdown approach. MATERIALS AND METHODS: Four carcinoma cell lines were investigated for the expression of the ΔNp63 isoform by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) (0, 24, 48 h) with and without single dose irradiation of 6 Gy. Furthermore, all cell lines were transfected with siRNA against the ΔNp63α isoform over 24 h. Knockdown effectiveness was controlled by qRT-PCR and Western blot. Apoptotic events were evaluated by terminal transferase dUTP nick end labeling (TUNEL) assay and cross-checked by a test for cell viability (WST-1, Roche) over 48 h. RESULTS: All cell lines presented varying expression of the ΔNp63α isoform with and without irradiation. A sufficient knockdown rate was established by siRNA transfection. Knockdown of the ΔNp63 isoform showed an effect on radiation sensitivity proven by an increase of apoptotic events detectable by immunofluorescence (TUNEL assay) and likewise a significant reduction of formazan production (WST-1 test) in three cell lines. CONCLUSIONS: We found overexpression of ΔNp63α with and without irradiation in three cell lines, and the knockdown of ΔNp63α led to increased apoptotic events and fewer viable cells. Thus, the overexpression of ΔNp63α might protect carcinoma cells against irradiation effects. CLINICAL RELEVANCE: The present work supports the hypothesis that protein 63 might serve as a negative predictor for irradiation response and survival in a clinical setting and may be a target for future therapeutic strategies.

A spectroscopic approach to monitor the cut processing in pulsed laser osteotomy.

During laser osteotomy surgery, plasma arises at the place of ablation. It was the aim of this study to explore whether a spectroscopic analysis of this plasma would allow identification of the type of tissue that was affected by the laser. In an experimental setup (Rofin SCx10, CO(2) Slab Laser, wavelength 10.6 µm, pulse duration 80 µs, pulse repetition rate 200 Hz, max. output in cw-mode 100 W), the plasma spectra evoked by a pulsed laser, cutting 1-day postmortem pig and cow bones, were recorded. Spectra were compared to the reference spectrum of bone via correlation analysis. Our measurements show a clear differentiation between the plasma spectra when cutting either a bone or a soft tissue. The spectral changes could be detected from one to the next spectrum within 200 ms. Continuous surveillance of plasma spectra allows us to differentiate whether bone or soft tissue is hit by the last laser pulse. With this information, it may be possible to stop the laser when cutting undesired soft tissue and to design an automatic control of the ablation process.

Prognostic parameters contributing to palatal implant failures: a long-term survival analysis of 239 patients.

OBJECTIVE: To evaluate the demographic, radiological and therapeutic parameters that influence the overall clinical performance of palatal implants subjected to orthodontic loading. PATIENTS AND METHODS: The data of all patients who had received an orthodontic palatal implant for skeletal anchorage between January 1998 and December 2007 were reviewed retrospectively. The primary endpoint was the implant loss. The following parameters were assessed by univariate (log-rank test) and multivariate (Cox's regression) analysis: (a) age and gender, (b) vertical bone height along the prospective implant axis, (c) surgeon's experience and (d) implant type. RESULTS: Two-hundred and thirty-nine palatal implants were inserted in patients aged between 10 and 65 years. In all, 11/239 (4.6%) implants were lost: nine during the healing phase and two under functional loading. On univariate analysis, "surgeon's experience" was associated with a better implant survival and vice versa (P=0.0005; log-rank test). The significance of "surgeon's experience" was confirmed by Cox's regression analysis (P=0.001; Wald test). All other parameters had no impact on implant loss. CONCLUSIONS: The survival probability of palatal implants is not related to demographic and radiological parameters. Implant losses mainly occurred early in the healing phase of the palatal implant. According to our data, "surgeon's experience" is the cornerstone of palatal implant success.

Isolated Hypoglossal Nerve Palsy as an Early Symptom of a Granular Cell Tumor.

BACKGROUND: Hypoglossal nerve palsy (HNP) is rather common as a neurological disease. However, as an isolated nerve palsy it is an exceedingly rare phenomenon and points at local pathologies along the peripheral course of the nerve. In this communication we report a granular cell tumor (GCT) arising in the submandibular segment of the hypoglossal nerve. CASE-REPORT: Spontaneous isolated HNP was recognized in a female patient. First line MR-imaging identified a clivus-chordoma. However, involvement of the hypoglossal nerve was highly unlikely according to MR-findings. Finally, ultrasonographic investigation revealed a small submandibular mass which, at histological examination, turned out to be a granular cell tumor arising within the hypoglossal nerve. CONCLUSIONS: This is the report of an extremely rare GCT originating within the 12th cranial nerve. The case illustrates that isolated motoric cranial nerve palsy may result from this rare tumor entity. This report also points out the diagnostic value of a simple ultrasonographic investigation to depict pathologic lesions of the submandibular space.

Vertical palatal bone dimensions on lateral cephalometry and cone-beam computed tomography: implications for palatal implant placement.

OBJECTIVES: To evaluate the necessity of three-dimensional imaging (computed tomography [CT]/cone-beam computed tomography [CBCT]) for paramedian insertion of palatal implants. MATERIAL AND METHODS: Lateral radiographs and CBCT scans were performed from 18 human skulls. For lateral cephalometry, the nasal floor (right/left) and the oral hard palate of all skulls were lined with a tin foil for contrast enhancement. The quantity of vertical bone as measured on lateral radiographs was compared with CBCT measurements obtained in median and parasagittal planes and at minimum bone height. Spearman's rank correlation coefficients were determined for bivariate correlation analysis. RESULTS: The median palatal bone height on CBCT (mean 8.98 mm; standard deviation [SD] 3.4) was markedly higher than the vertical height seen on lateral radiographs (mean 6.6 mm; SD 3.2). Comparing lateral cephalometry with CBCT, the strongest association was observed at the minimum palatal bone height (r=0.926; P<0.001; Spearman's rank correlation coefficient). CONCLUSIONS: Lateral radiographs allow accurate and adequate assessment of vertical bone before paramedian insertion of palatal implants. The vertical bone dimension as displayed on lateral cephalometry reflects the minimum bone height rather than maximum bone in the median plane. Therefore, a preoperative CT or CBCT is only indicated when the lateral cephalometry reveals a marginal quantity of bone.

Diagnostic efficiency of differentiating small cancerous and precancerous lesions using mucosal brush smears of the oral cavity--a prospective and blinded study.

The aim of this study was to evaluate the diagnostic accuracy of oral brush biopsy to identify early malignancy. One hundred and eighty-six brush biopsies of suspicious mucosal lesions were obtained, haematoxilin and eosin (H&E)-stained and compared with the histology of conventional excision biopsies of the same site performed concomitantly. The sensitivity for identifying squamous cell carcinoma (SCC) was 88.5%. High-risk lesions including squamous intraepithelial neoplasia (SIN II, SIN III) and SCC were identified with a sensitivity of 86.4%, using a pap-analogous classification, which is considered to be carcinomatous, as well as moderate and severe dysplastic cells positive. Depending on the cytopathologic definition for malignancy and the tumour size, the test accuracy varied: Extending the cytopathologic criteria for malignancy by defining all dysplastic or malignant cytopathologic findings as positive, the sensitivity was increased to 95.2% at the expense of the specificity, which was reduced from 94.9% to 82.3%. Separately analysing SCCs of less than 20 mm, the sensitivity was reduced by 9.5% to 78%. Although small malignant lesions seem to be less reliable by the conventional oral brush biopsy, it is a useful screening instrument for early diagnosis of suspicious, epithelial lesions and could therefore contribute to improved cancer prognosis.

Effectiveness of autofluorescence to identify suspicious oral lesions--a prospective, blinded clinical trial.

Regular screening through white light inspection of the entire oral mucosa is the most important examination method to identify precancerous lesions and early oral carcinoma. Additionally, the physiologic autofluorescence of the oral mucosa has been described as a novel screening method for the detection of mucosal lesions that are not visible by white light. This study aimed to evaluate the sensitivity and specificity of the autofluorescence examination. Seventy-eight patients were examined in this study. All of them suffered from suspicious oral mucosal lesions. Two different investigation methods were applied: the standard examination by white light and an examination by a novel light source of 400 nm that evoked a green light emission (>500 nm) in normal mucosa. It was proposed that malignant oral mucosal lesions show different autofluorescence characteristics than the green autofluorescence of healthy mucosa. Red autofluorescence indicated SCC with a sensitivity of 20% and a specificity of 98%. The results showed that dysplasia and carcinoma could be identified with a sensitivity of 96% and a specificity of 18% by using the autofluorescence method. The sensitivity decreased according to the grade of mucosal keratosis and was influenced by the localisation of the lesion. In conclusion, benign as well as malignant oral lesions could not be distinguished by a diminished autofluorescence signal. A red autofluorescence signal, however, could indicate cancerous processes of the oral mucosa.

Immediate versus conventional loading of palatal implants in humans: a first report of a multicenter RCT.

This study aims to analyze the clinical performance of two loading concepts on second-generation palatal implants (Orthosystem, Straumann, Basel, Switzerland) in a prospective multicenter randomized controlled clinical trial. At the time of this interim analysis, 41 patients have been randomized on a 1:1 basis to one of two treatment groups. Group 1 underwent conventional loading of palatal implants after a healing period of 12 weeks (gold standard) while group 2 underwent immediate implant loading within 1 week after implant insertion. We report initial results at 6 months after functional loading. The primary outcome parameter was implant success (no implant mobility, no implant loss). The implants in both groups were initially stable at the time of insertion, and all were eligible for randomization. Twenty-two patients (group 1) were subjected to conventional implant loading after 12 weeks while 19 patients (group 2) received immediate functional loading within the first week after insertion. Direct (e.g. distal jet appliances) as well as indirect forms of anchorage (conventional or modified transpalatal arch) were used. The magnitude of orthodontic forces ranged between 1 and 4 N for the immediate loading group and between 1 and 5 N for the conventional loading group. One implant in group 1 was lost during the healing phase. One dropout was registered in group 2. Thirty-nine implants were functionally loaded for over 6 months now. These preliminary data provide first evidence of the fact that immediate loading of palatal implants yields equivalent success rates as conventional loading to 4 N after 6 months.

Immediate implant placement and provisionalization after long-axis root fracture and complete loss of the facial bony lamella.

The aim of this research was to explore the performance of a flapless surgical approach for immediate implant placement, simultaneous alveolar ridge augmentation, and immediate provisionalization in patients with complete loss of the facial bony lamella resulting from long-axis root fracture. Eighteen NobelPerfect implants were placed in 16 patients (follow-up, 13 to 36 months) who had sustained complete loss of the facial bony lamellae. Implants were inserted simultaneous to subperiostal bone augmentation with autogenous bone chips and underwent immediate provisionalization. Outcome variables included implant success, marginal bone levels, and pink esthetic score (PES). All implants achieved excellent primary stability. There were no implant losses. On average, interproximal marginal bone levels stabilized at 1.0 to 1.3 mm above the first thread. Postoperative cone beam computed tomography scans were available for 16 implant sites and confirmed restoration of the facial lamella in the vast majority of patients. Marginal esthetics, as assessed by the PES, was by and large preserved (mean postoperative PES, 12.5). Oral hygiene was highly predictive for the esthetic result. Survival rates, marginal bone levels, and esthetic results suggest a proof-of-principle for the new flapless immediate implant placement technique in patients with complete loss of the facial bony lamella. Oral hygiene status may be considered as a negative prognostic factor for the esthetic outcome.

Inducible NO synthase confers chemoresistance in head and neck cancer by modulating survivin.

The dual role of the inducible NO synthase (iNOS) and NO signaling in head and neck squamous cell carcinoma (HNSCC) is a complex and can both promote or inhibit tumor progression. However, the underlying molecular mechanisms are not yet resolved in detail. We show for the first time that conditions, favoring low NO levels conferred resistance against cisplatin/taxol-induced apoptosis in HNSCC cell lines. Cytoprotection was mediated by survivin, because we observed its upregulation subsequent to low doses of the NO donors S-nitroso-N-acetyl-penicillamine (SNAP) and sodium nitroprusside (SNP) or ectopic expression of physiologic amounts of iNOS. Also, RNAi-mediated depletion of survivin blocked NOs anti-apoptotic effects. Induction of survivin involves activation of the phosphatidylinositol-3-kinase/Akt (PI3K/Akt) pathway, which was antagonized by the PI3K-inhibitor LY294002. Importantly, application of the iNOS-specific inhibitor 1400W combined with RNAi-mediated downregulation of survivin cooperatively enhanced drug-induced cell death. The iNOS/survivin-axis appears to be also of clinical relevance since immunohistochemistry revealed that iNOS expression correlated with enhanced survivin levels in HNSCC specimens. In contrast, high NO concentrations suppressed survivin levels in HNSCC but also in non-malignant cells resulting in apoptosis. Cell death induced by high amounts of SNAP/SNP or by strong overexpression of iNOS involved activation of p38MAP-kinase, which was counteracted by the p38MAP-kinase inhibitor SB202190. Here, we provide evidence for a novel molecular mechanism how NO signaling may contribute to therapy resistance in HNSCC by modulating survivin expression. Our data further suggest pursuing pharmacogenetic iNOS/survivin-targeting approaches as potential therapeutic strategies in head and neck cancer.

Immediate vs. conventional loading of palatal implants in humans.

OBJECTIVES: To analyze the clinical performance and bone-to-implant contact (BIC) rate of two loading concepts on successfully healed and explanted palatal implants in humans. METHODS: From 2000 to 2006, two independent groups of patients, requiring maximum anchorage, were treated. Group 1 (n=36) was subjected to immediate functional loading within the first 24 h after insertion while group 2 (n=40) received conventional implant loading after 12 weeks. The magnitude of orthodontic forces ranged between 1 and 3 N. After orthodontic treatment, the implants were removed with a trephine drill. Histological workup by the cutting and grinding technique was performed for nearly the last third of palatal implants. Outcome variables were clinical implant survival and histological BIC rates. RESULTS: The implants in both groups were initially stable at the time of insertion. However, 3/36 in group 1 and 1/40 in group 2 were lost. The remaining implants were clinically stable and no mobility was recognized. The median BIC rates were 76% (SD, 25) in group 1 (n=10) and 84% (SD, 13) in group 2 (n=12) (P=0.262; Mann-Whitney U-test, not significant). CONCLUSIONS: The data support the concept of immediate indirect loading on palatal implants with forces of up to 3 N. On histological evaluation, immediate loading yielded similar BIC rates as conventional loading.

Success rate of second-generation palatal implants.

OBJECTIVE: To analyze the clinical outcome of a prospective two-center study of second-generation palatal implants 6 months after functional loading. MATERIAL AND METHODS: From 2005 to 2006, 30 patients aged 12 to 41 years were included in the study. In all patients, orthodontic treatment required stationary anchorage. The palatal implants (Straumann, Basel, Switzerland) were placed in the median region of the anterior palate. RESULTS: All implants were initially stable at the time of placement. However, two (6.7%) were lost during the unloaded healing period. The remaining 28 (93.3%) were subjected to functional loading after a mean healing period of 12 weeks. Typical signs of slight superficial inflammation were observed in the peri-implant mucosa (n = 28). During the orthodontic loading phase, the implants were equipped with either a modified pendulum appliance for distalization or a transpalatal arch for stationary anchorage to the posterior teeth. No implant loosening or loss was registered during the active treatment period. CONCLUSIONS: The failure rate of palatal implants of the second generation was low (6.7%). Slight inflammatory reactions of peri-implant tissue caused neither implant loss nor pain.