Transsinusoidal lateral nasal floor augmentation for implant placement in the atrophic premaxilla: A within-patient, 5-year, prospective comparative study.

OBJECTIVES: To evaluate the clinical outcome for implants placed with transsinusoidal-lateral nasal cavity augmentation (NA) compared to implants placed in maxillary sinus augmentation (SA). MATERIALS AND METHODS: In 28 atrophic edentulous maxillary regions (14 patients bi-maxillary), a lateral window approach was used to perform transsinusoidal-lateral NA (TSLNA) combined with maxillary SA. After healing period of about 6 months, each patient received bimaxillary one anterior implant located in the pre-maxilla having lateral NA and 2-3 implants in the maxillary posterior region with SA. In a prospective follow-up evaluation, clinical implant outcome (survival/success rates) and peri-implant health (mucositis/peri-implantitis) were assessed and compared between implants placed in TSLNA (n = 28) and SA (n = 58). RESULTS: At the year-1, year-3, and year-5 evaluation, neither patient-based nor implant-based comparisons revealed differences for marginal bone level reduction between implants placed in TSLNA (5-year overall: 1.11 ± 0.26 mm) and SA (5-year overall: 1.07 ± 0.30 mm), although with a significant (p < .001) continuous reduction over the observation time. At the year-5 evaluation, all implants (n = 86) and restorations (n = 14) were still in situ (survival 100%) and showed an implant-based incidence of peri-implant mucositis/peri-implantitis of 14.3%/0% in TSLNA and 6.9%/3.4% in SA corresponding to 21.4%/0% and 28.6%/7.1% for implant-based evaluation. In addition, the implant success rate did not differ between NA and SA at implant- (100%/ 98.8%) and patient-based (100%/97.6%) evaluation. CONCLUSION: The findings obtained show TSLNA as an effective method for implant placement of adequate length and direction in the atrophic premaxilla providing for success rates comparable to those of implants placed in SA.

Clinical, radiographic, and histological/histomorphometric analysis of maxillary sinus grafting with deproteinized porcine or bovine bone mineral: A randomized clinical trial.

OBJECTIVE: The present study aimed to compare histomorphometrically evaluated new bone formation, radiographically measured graft stability, and clinical implant outcome between maxillary sinus grafting with either deproteinized porcine bone mineral (DPBM) or deproteinized bovine bone mineral (DBBM). MATERIALS AND METHODS: Thirty maxillary sinuses were initially included and randomly assigned to the test group (TG; DPBM, n = 15) or control group (CG; DBBM, n = 15). After a healing period (6 months), axially retrieved bone biopsies of the molar region were used for histological/histomorphometric analysis of new bone formations. Additionally, radiographically measured graft stability and clinical implant outcome were assessed. RESULTS: Twenty-three sinus sites with 10 sinuses of the TG and 13 of the CG were ultimately available for data and statistical analysis. In the TG, a slightly, but yet significantly (p = .040) higher proportion of new bone formation (TG: 27.7 ± 5.6% vs. CG: 22.9 ± 5.1%) and a lesser (p = .019) amount of connective (non-mineralized) tissue (TG: 47.5 ± 9.5% vs. CG: 56.1 ± 9.5%) was found than in the CG. However, both xenografts showed comparable (n.s.) residual bone graft (TG: 23.7 ± 7.2% vs. CG: 21.1 ± 9.85.6%), bone-to-graft contacts (TG: 26.2 ± 9.8% vs. CG: 30.8 ± 13.8%), similar graft height reduction over time (TG: 12.9 ± 6.7% CG: 12.4 ± 5.8%) and implant survival/success rate (100%). At the 3-year post-loading evaluation, the peri-implant marginal bone loss (TG: 0.52 ± 0.19 mm; CG: 0.48 ± 0.15 mm) and the peri-implant health conditions (TG: 87.5%/CG: 81.2%) did not differ between implants inserted in both xenografts used. CONCLUSIONS: The use of DPBM or DBBM for maxillary sinus augmentation is associated with comparable bone formation providing stable graft dimension combined with healthy peri-implant conditions.

Platelet-rich fibrin vs. buccal advancement flap for closure of oroantral communications: a prospective clinical study.

OBJECTIVES: The primary aim was to evaluate the success of the defect closure (tight or open) of oroantral communications (OAC) after treatment with platelet-rich fibrin (PRF) clots or a buccal advancement flap (BAF). Secondary outcome measurements were the evaluation of the wound healing, the displacement of the mucogingival border (MGB), and the pain level. MATERIAL AND METHODS: Fifty eligible patients with an OAC defect larger than 3 mm were randomly assigned to either PRF (test group, n = 25) or BAF (control group, n = 25) for defect closure. In a prospective follow-up program of 21 days, the defect closure healing process, the wound healing course using Landry's wound healing index (score: 0-5), the displacement of the MGB, and the postoperative pain score were evaluated. RESULTS: Five patients in each group were lost to follow-up resulting in 40 patients (20 in each group) for continuous evaluation. On postoperative day 21 (study endpoint), no difference regarding success rate (defined as closure of OAC) was noticed between the test (90%; 18/20) and control group (90%; 18/20). A univariate analysis showed significant differences for age and defect size/height for the use of PRF between successful-tight and open-failed defect healing. At the final evaluation, a significantly (p = 0.005) better wound healing score, a lower displacement of the MGB as well as lower pain-score were seen for the use of PRF. CONCLUSIONS: Based on the findings of the current study, the use of platelet-rich fibrin represents a reliable and successful method for closure of oroantral communications. The use of PRF clots for defect filling is associated with lowered pain levels and less displacement of the mucogingival border. CLINICAL RELEVANCE: The defect size should be taken into account when choosing the number and size of PRF plugs.

Forced surgical extrusion using an axial tooth extraction system as a practicable technique for preserving severely destroyed teeth? - Clinical outcomes up to 4.8 years.

OBJECTIVE: Several extrusion techniques have been described to restore teeth with insufficient coronal tooth structure and to avoid their extraction. Still, there is little evidence for a treatment concept combining surgical extrusion using an atraumatic axial extraction system. MATERIALS AND METHODS: A total of nine patients, each with an iso- or subgingival fractured tooth, were retrospectively examined. Treatment of the damaged tooth comprised an atraumatic forced surgical extrusion performed with an axial tooth extraction system and a more coronal positioning within the socket. The teeth were initially splinted and subsequently restored. The follow-up period was up to 57.1 months and averaged 36.5 (SD: ±13.5) months. RESULTS: All nine teeth were still in situ, without signs of inflammation. During the period of the provisional restoration, six prosthetic complications occurred, which were resolved with little effort, whereas, success rate for the definitive restoration was 100%. No biological complications were observed concerning the root apex or soft tissue. The radiographically measured mean extrusion distance was 3.4 (SD: ±1.0) mm, so that a sufficient prosthetic ferrule could be reestablished. CONCLUSIONS: Surgical extrusions using an axial tooth extraction system demonstrate low biological and prosthetic complications rates over observation time. CLINICAL SIGNIFICANCE: The presented extrusion approach preserves soft and hard tissue and is an efficient treatment option for severely destroyed teeth. Saving hopeless teeth by this relatively predictable and feasible procedure has hardly any disadvantages for patients, and in case of failure, an implant or fixed partial denture are still an option.

Immediately loaded implants simultaneously placed in fresh extraction and healed sites supporting four-implant-supported fixed mandibular prostheses using the all-on-4 concept: A 5-year prospective study.

OBJECTIVES: To evaluate the peri-implant marginal bone level for immediately loaded implants placed simultaneously in both fresh extraction sites (FES) and healed sites (HS) supporting a 4-implant supported mandibular fixed prosthesis (4-ISFMP) using the all-on-4 concept. MATERIAL AND METHODS: A 5-year prospective study was conducted in 24 patients (96 implants) treated with 4-ISFMP including 55 implants inserted in FES and 41 implants in HS. At implant placement (baseline) and at the 1st -, 3rd - and 5th -year follow-up examinations, peri-implant marginal bone level was evaluated radiographically and compared between placement in FES and HS. Marginal bone loss was calculated as the difference in the marginal bone level evaluated at the follow-up periods. Additionally, implant and prosthesis survival rates as well as the presence of peri-implant mucositis (bleeding on probing+[BOP]) and peri-implantitis (BOP+ >2 mm MBL) were evaluated. RESULTS: 22/24 patients with 88/96 implants (dropout rate: 8.3%) were continually followed for 5 years (survival rate: 100%). Radiographically measured marginal bone level differed significantly between FES and HS at implant placement (1.46 ± 0.80 mm vs. 0.60 ± 0.70 mm; p < .001), at the 1-year (-0.04 ± 0.14 mm vs. -0.18 ± 0.20 mm; p = .002) and 3-year (-0.26 ± 0.49 mm vs. -0.58 ± 0.48 mm, p = .049), but not at the 5-year evaluation (-0.90 ± 0.66 mm vs. -1.00 ± 0.59 mm, p = .361). The marginal bone loss differed significantly (p < .001) between FES and HS between implant placement and the 1-year evaluation but not for the 1- to 3-year (p > .99) and the 3- to 5-year period (p = .082). At the 5-year follow-up evaluation, no implant/prosthesis failed (100% survival) and peri-implant mucositis and peri-implantitis were noted in 41.2% and 11.7% at patient level and in 17.6% and 4.5% at implant level respectively. CONCLUSION: Implants placed in FES showed a prolonged peri-implant remodelling process but provided for similar peri-implant marginal bone levels as implants placed in HS at the 5-year evaluation for immediately loaded 4-ISFMP.

Use of amniotic membrane for radial forearm free flap donor site coverage: clinical, functional and cosmetic outcomes.

OBJECTIVE: To evaluate the clinical, functional and aesthetic outcomes for radial forearm free flap (RFFF) donor sites covered with amniotic membrane (AM). MATERIAL AND METHODS: The healing process of patients with RFFF donor sites covered with AM was prospectively followed for 1 year. Additionally at the 12-month evaluation, objective scoring systems were used to assess the aesthetic (Vancouver scar scale, VSS: range 1-13) and functional outcome (skin sensibility, hand/wrist functionality [goniometer], grip strength [score 1 = excellent, 5 = poor]). By using a subjective rating system (score 1 = excellent, 5 = poor), the patient-reported aesthetic and functionality outcome was correlated with objective data analysis. RESULTS: Twenty-one out of 23 patients were followed for 12 months (dropout: 2 patients at 3 months). In 17/23 (73.9%) patients RFFF defect covered with AM showed an uneventful healing period (< 3 months). Prolonged healing periods (> 3 months < 6) for 6 patients (26.1%) were attributed to wound infections (4×), seroma (1×) and inflammation (1×). At the 1-year evaluation, there was a significant (p < 0.01) correlation between subjective (2.0 ± 0.71) and objective aesthetic scores (VVS 3.74 ± 2.18), and a successful grip strength (score 1.67 ± 0.86); however, thumb hyposensibility in 76.2% was seen. A high body mass index (BMI) was in conjunction with a negative (p = 0.012) and the use of antihypertensive medications provided positive effects (p = 0.041) on the aesthetic outcome. CONCLUSION: RFFF donor site defects covered using AM show excellent clinical, aesthetic and functional outcome representing patient comorbidities (BMI, antihypertensive drugs) might affect the aesthetic outcome. CLINICAL RELEVANCE: In relation to the excellent outcomes found, the use of AM offers an alternative treatment procedure for RFFF defect covering.

Mechanical stability of all-ceramic abutments retained with three different screw materials in two-piece zirconia implants-an in vitro study.

OBJECTIVES: To measure the abutment rotation and fracture load of two-piece zirconia implants screwed with three different abutment screw materials. MATERIAL AND METHODS: Thirty-six zirconia implants with 36 zirconia abutments were distributed into 3 test groups: group G connected with gold screws, group T with titanium screws, and group P with peek screws. In the first part of the study, the rotation angle of the abutments was measured. The second part of the study measured the maximum fracture force of adhesively bonded lithium disilicate crowns after artificial aging and fracture modes were reported. RESULTS: In group G, the median rotation angle was 8.0°, in group T 11.6°, and in group P 9.5°. After artificial aging, no screw loosening, crown, abutment, or implant fracture occurred. The median fracture force in group G was 250 N, in group T 263 N, and in group P 196 N. CONCLUSIONS: Rotation angles and fracture loads of two-piece zirconia implants with gold, titanium, or peek screws showed no significant differences; however, fracture loads showed inferior results for group P. CLINICAL RELEVANCE: The indication for the material peek as an abutment screw is still questionable and should be considered carefully.

Accuracy and reproducibility of four cone beam computed tomography devices using 3D implant-planning software.

OBJECTIVE: To measure the deviations of four different cone beam computed tomography (CBCT) devices in three dimensions by means of a three-dimensional (3D) implant-planning program. MATERIALS AND METHODS: A master radiographic template with two vertical, two transverse, and two sagittal radiopaque markers was fabricated for a human dry skull. The lengths of the markers were measured with a high-precision caliper. The skull and the template were scanned in each of the four CBCT devices (1. Gendex GXCB-500; 2. Sirona Galileos Comfort; 3. Sirona Orthophos XG 3D; 4. Carestream CS 9300) 19 times (10 scans without moving the skull, and 9 scans with repeated repositioning of the skull in the device, according to the manufacturers' instructions). A 3D implant-planning program was used to measure the lengths of the six markers digitally. Actual and digital measurements were compared to determine device-specific errors. The repositioning of the skull examined the reproducibility of the CBCT devices. Linear measurements were analyzed statistically (P < 0.05). RESULTS: Mean deviations without moving the skull (vertical/sagittal/transverse) for device 1 were 0.023 mm/0.000 mm/0.025 mm (0.07%/0.19%/0.24%), for device 2 were 0.410 mm/0.115 mm/0.080 mm (-1.75%/0.32%/0.88%), for device 3 were -0.665 mm/-0.215 mm/-0.675 mm (-2.71%/-1.82%/-4.42%), and for device 4 were -0.045 mm/-0.135 mm/-0.410 mm (-0.45%/-1.54%/-2.57%). The overall mean deviation for device 1 was 0.028 mm (0.16%), for device 2 was 0.072 mm (-0.95%), for device 3 was 0.518 mm (-2.97%), and for device 4 was -0.197 mm (-1.53%). The mean deviation after repositioning for device 1 was 0.004 mm (-0.65%), for device 2 was -0.250 mm (0.95%), for device 3 was 0.496 mm (-2.66%), and for device 4 was -0.265 mm (-1.92%). Thus, apart from device 3, the deviations increased. CONCLUSION: Deviations from the actual measurements were detected with each device. Therefore, respecting safety distances when placing implants is crucial.

Precise Placement of Single-Retainer Resin-Bonded Fixed Dental Prostheses with an Innovative Splint Design.

Single-retainer resin-bonded fixed dental prostheses (RBFDPs) are difficult to position due to the pressure of soft tissue at the pontic area and the single-retainer design. This clinical report describes an innovative technique for the insertion of single-retainer RBFDPs. An incisal inserting splint is used to position the RBFDPs reliably. With the help of grooves in the buccal and incisal area of the splint, the precise positioning of the splint on the adjacent teeth and the RBFDP can be controlled. Also, a hole in the retainer wing region of the splint gives access for pressure application on the wing during the bonding process. With the aid of this method, 25 single-retainer FBFDPs were inserted in the correct position in a case series. The splint described here allows the precise insertion of single-retainer RBFDPs and simplifies delivery.

Factors affecting peri-implant bone resorption in four Implant supported mandibular full-arch restorations: a 3-year prospective study.

BACKGROUND: Peri-implant marginal bone-level (MBL) alteration represents one of the parameters included in the criteria for determining implant health. OBJECTIVE: Factors affecting peri-implant MBL alteration for 4-implant-supported fixed mandibular prostheses (4-ISFMP) were assessed. MATERIAL & METHODS: A 3-year prospective, cohort study was conducted on 44 mandibularly edentulous patients treated with 4-ISFMP. Peri-implant MBL alteration was evaluated radiographically at the 12-, 24- and 36-month follow-ups considering to patient-related risk factors [age, gender, diabetes mellitus, smoking, cardiovascular disease (CVD), rheumatic disorders (RD)] and implant/prosthesis-related features (implant location, keratinized gingiva, denture cantilever length, prosthesis supporting zone, opposing dentition) as well as to peri-implant biological parameters (plaque-, bleeding-, calculus index). RESULTS: 148/176 implants (37 patients, drop-out: 15%) were followed for 3 years showing significant (p < 0.001) annual differences of MBL alterations over time. The univariate analysis demonstrated differences of MBL alterations for smokers (p = 0.014), for patients with CVD (p = 0.001) and RD (p = 0.011). In the 3-year multivariate analysis, MBL alteration was influenced by time (p < 0.001) and showed relationship with risk factors as smoking (p < 0.002; OR = 18.965), CVD (p < 0.021; OR = 5.172), RD (p < 0.006; OR = 50.171) and plaque-index (p = 0.034; OR = 3.252). CONCLUSIONS: Although peri-implant MBL alteration increased annually, significant odds ratios, were found for patients-related risk factors identifying them potentiating the alterations.

Maxillary Sinus Augmentation with Anorganic Bovine Bone Mineral of Different Particle Sizes: A Split-Mouth Study with Histomorphometric, Radiographic, and Clinical Analyses.

PURPOSE: The aim of the present study was to compare the histomorphometrically evaluated new bone formation (NB), the radiographically measured graft stability, and the clinical implant outcome for maxillary sinus augmentation grafted with deproteinized bovine bone mineral (DBBM) with either small (Bio-Oss-S, Geistlich) or large (Bio-Oss-L, Geistlich) particles. MATERIALS AND METHODS: Using a split-mouth study design, bilateral maxillary sinus augmentation was performed in 13 patients either with Bio-Oss-S particles (0.25 to 1 mm) or Bio-Oss-L particles (1 to 2 mm). After a healing period of 6 months, bone biopsies were axially retrieved in the molar region for histologic/histomorphometric analysis of NB, including subsequent staged implant placement. To determine graft stability, the maxillary sinus augmentation vertical graft heights were radiographically measured immediately after sinus augmentation, at implant placement, and at the 2- and 4-year post-augmentation follow-ups. In addition, the clinical implant-prosthodontic outcome (survival/ success/marginal bone loss) was assessed at 1 and 3 years post-loading. RESULTS: A total of 22 sinuses from 11 patients with split-mouth evaluation were ultimately available for data and statistical analysis. Histomorphometric analysis of the axially retrieved bone biopsies revealed the presence of NB (S: 25.5% ± 7.0% vs L: 23.6% ± 11.9%; P = .640), residual graft particles (S: 19.6% ± 9.2% vs L: 17.5% ± 6.3%; P = .365) as well as connective tissue (S: 54.9% ± 9.2% vs L: 58.9% ± 12.5%; P = .283), without significant differences between the use of small (Bio-Oss-S) and large (Bio-Oss-L) particles. However, there was significantly (P = .021) higher bone-to-graft contact (BGC) for the small-particle graft sites (27.9% ± 14.8%) compared to the large-particle graft sites (19.9% ± 12.9%), representing a significantly higher osteoconductivity. Both particle sizes showed significant (P < .01) vertical graft height reduction over time (4 years) of about 10%, with predominant graft reduction in the time period between sinus augmentation and implant placement compared to any follow-up periods after implant placement. At the 3-year post-loading implant evaluation, all implants and prostheses survived (100%), and the peri-implant marginal bone loss (S: 0.52 ± 0.19 mm; L: 0.48 ± 0.15 mm) as well as the peri-implant health conditions (S: 87.5%, L:81.2%) did not differ between implants inserted with the two different xenograft particles used. CONCLUSIONS: The use of small and large bovine xenograft particles for maxillary sinus augmentation provides for comparable bone formation, ensuring stable graft dimensions combined with high implant success and healthy peri-implant conditions. However, small particle size resulted in a higher BGC, providing for higher osteoconductivity than with the larger particle size.

Efficacy of Labial Split-Thickness Eversion Periosteoplasty for Soft Tissue Management in Posterior Mandibular Horizontal Ridge Augmentation Procedures: A Prospective Clinical Study.

Purpose: To evaluate the efficacy of split-thickness labial eversion periosteoplasty (EPP) for soft tissue closure in horizontal ridge augmentation of posterior mandibular regions using a bone shell onlay grafting technique. Materials and Methods: Sixteen patients (12 female and 4 male; mean age: 46.2 ± 8.7 years) with 18 horizontal bone defects in posterior mandibular regions were included for lateral onlay bone grafting using the bone shell technique. After lateral bone augmentation, the EPP was used for soft tissue closure and was prospectively followed up for wound healing efficacy using a modified scoring index. The scoring index included dichotomous (yes: 0 / no: 1) evaluation of the following items: (1) bleeding on palpation or spontaneously, (2) tissue color difference, (3) presence of hematoma, (4) presence of granulation tissue, (5) incomplete incision margin closure, (6) dehiscence with visible augmentation material, (7) presence of exudation, and (8) presence of suppuration. In addition, a visual analog scale (VAS) was used to quantify and record the amount of pain and swelling (0 = no pain/swelling and 5 = severe pain/swelling); VAS scores of 0, 1, and 2 were rated as 1 in the dichotomous scoring index, and VAS scores of 3, 4, and 5 were rated as 0. A summarized wound healing score consisting of all 10 items was assessed at days 2, 7, and 14 and at months 1 and 4 postoperatively, including a comparison of the follow-up evaluations. Results: The summarized healing score increased significantly (P < .01) between day 2 (score: 6.6 ± 1.1) and day 7 (score: 8.9 ± 1.0) but showed little difference between day 14 (score: 9.6 ± 0.6) and the 1- and 4-month follow-ups (score: 10.0 ± 0). There was no wound dehiscence and no incomplete incision margin adaptation. For the individual parameters evaluated, bleeding on palpation, hematoma, and exudation were the most frequent side effects at day 2 at 50%, 100%, and 22.2%, respectively, and at day 7 at 16.7%, 55.6%, and 22.2%, respectively. The average pain score and the swelling/edema score were initially 4.0 ± 0 and 3.0 ± 0.77 on day 2, with a significant decrease (P < .001) by day 7 (pain: 2.0 ± 0; edema/swelling: 2.0 ± 0.59) and day 14 (pain: 1.0 ± 0.42; edema/swelling: 2.0 ± 0.79) and complete absence (score: 0) at months 1 and 4. Conclusions: Labial split-thickness EPP facilitates flap advancement and enables tight soft tissue coverage in large horizontal posterior mandibular bone augmentations as a result of offset double-layer wound closure. Although this procedure is shown to be surgically demanding, the postoperative complication rate may be reduced significantly.

Removable four implant-supported mandibular overdentures rigidly retained with telescopic crowns or milled bars: a 3-year prospective study.

PURPOSE: The present study evaluated implant survival/success rate, peri-implant parameters and prosthodontic maintenance efforts for four implant-supported mandibular overdentures (IOD) rigidly retained on either milled bar or double crowns (telescopic) attachments. MATERIAL AND METHODS: In a randomized prospective trial, 51 patients with edentulism received four mandibular interforaminal implants and complete maxillary dentures. For IOD, rigid denture stabilization was chosen randomly selecting 26 patients for milled bars (group I) and 25 patients for double (telescopic) crowns (group II). During a 3-year follow-up period, implant survival/success, peri-implant parameters (marginal bone resorption, pocket depth, plaque-, bleeding-, gingival index [BI and GI], calculus) and prosthodontic maintenance efforts were evaluated and compared between both retention modalities used. RESULTS: Forty-five patients (23 group I, 22 group II) were available for a 3-year follow-up (dropout rate: 11.8%) presenting a high implant survival/success rate (100%). Peri-implant marginal bone resorption, pocket depth as well as BI and GI did not differ for both rigid retention modalities. However, annually higher values for plaque- (NS) and calculus index (P<0.035) were noticed for the bar (group I) than for the telescopic crown (group II) attachments. Prevalence of prosthodontic maintenance did not differ between both retention modalities (group I: 0.41/maintenance efforts/year/patients vs. group II; 0.45 maintenance/efforts/year/patients). However, prosthodontic adaption for handling mechanism showed benefits for the bar retention. CONCLUSION: Rigid anchoring of IOD retained either by bar or telescopic attachments showed high implant success rates and minor prosthodontic maintenance efforts regardless of retention modalities used. Stable denture retention presented healthy peri-implant structure for implants in bar and telescopic anchoring systems. Drawbacks such as higher plaque/calculus for bar retention and less favorable handling properties (output) for telescopic crown attachment leave the decision on the selection at the discretion of the clinician.

The influence of different forms of sinus membrane perforation on the prevalence of postoperative complications in lateral window sinus floor elevation: A retrospective study.

BACKGROUND: Maxillary sinus membrane perforation (SMP) during lateral window sinus floor elevation (SFE) might be associated with postoperative complications (PC). OBJECTIVES: To evaluate the prevalence of PC and clinical implant outcome for different forms of SMP with lateral window SFE. MATERIAL AND METHODS: The prevalence of PC such as maxillary sinusitis, graft necrosis and wound infection was retrospectively evaluated for 434 lateral window SFE (334 patients) with 331 SFE (241 patients) without and 103 SFE (93 patients) with SMP. SMP was additionally classified into four subgroups regarding to membrane perforation size (small-moderate [<10 mm] vs. large [>10 mm]) and membrane biotype ([BT] thin vs. thick). Additionally, patient- and surgery-related risk factors affecting PC and the 1-year implant survival rate were evaluated for SFE without and with SMP and subgroups. RESULTS: A significantly higher prevalence including significant odds ratios of PC such as maxillary sinusitis (10/103 [9.7%] vs. 4/331 [1.2%]; p < 0.021; OR: 8.85; p < 0.021) and graft necrosis (7/103[6.8%] vs. 1/103[0.3%]; p < 0.017; OR:7.43; p < 0.017) was found for SFE with than without SMP. The SMP subgroup with large size and thin BT involved significantly (p < 0.005) more PC (15/20[75%]) than all other SMP subgroups (5/20[25%]). For the risk factors evaluated the univariate analysis demonstrated differences of PC for the presence versus absence of SMP (p < 0.001) and for thin versus thick sinus mucosa (p < 0.038; p < 0.006) but not for sex, smoking, sinus septa and surgical stage. In the multivariate risk factors analysis, PC were significantly related to risk factors such as large size with thin BT (OR:18.049; p < 0.007). The 1-year implant survival rate did not differ between SFE without (99.5%) and with SMP (99.1%), regardless of successfully repaired subtype of SMP. CONCLUSION: The synopsis of perforation size and membrane biotype is crucial in differentiating different forms of SMP assessing and anticipating different prevalences of PC in lateral window SFE.

Influence of butt joint connections with long guiding areas on the stability of single crowns and 3-unit bridges - an in-vitro-study.

Purpose The aim of this study was to evaluate the stability of single crowns and 3-unit bridges in relation to the implant-abutment complex with and without tube in tube connection.Methods 60 specimens with a total of 90 implants (diameter 3.8 mm) were fabricated and distributed into 4 groups: CST (Crown with short tube), CLT (crown with long tube), BNT (Bridge without tube) and BLT (bridge with long tube). All superstructures consisted of one-piece hybrid abutment restorations out of monolithic zirconia, bonded on prefabricated titanium bases and were directly screwed into the implants. Specimen underwent artificial aging (2.000.000 cycles, 120 N, 30° off axis) and were subsequently loaded in an universal testing machine at an angle of 30° until failure. The specimens were examined for damage during and after artificial aging.Results During artificial aging, one test specimen of group CLT and two test specimens of group BNT failed. The average failure load was 498.8 (± 34.4) N for CLT, 418.8 (± 41.5) N for CST, 933.1 (± 26.2) N for BLT and 634.4 (± 29.0) N for BNT, with a statistical differences (p ˂ 0.001) between the crown and bridge groups. All tested samples exhibited macroscopic deformations at the implant shoulder, which were more pronounced in the specimens without a tube in tube connection.Conclusions Single crowns and 3-unit bridges with a long tube in tube connection showed significantly higher fatigue fracture strength compared to restorations with short or without tube in tube connection.

Prevalence, risk factors, and repair mechanism of different forms of sinus membrane perforations in lateral window sinus lift procedure: A retrospective cohort study.

OBJECTIVES: To evaluate prevalences, affecting risk factors and efforts for repair mechanism for different forms of sinus membrane perforations (SMP) during sinus floor elevation (SFE) using the lateral window technique (LWT). MATERIAL AND METHODS: For 334/434 patients, SFE undergoing LWT prevalence of SMP was retrospectively evaluated including a subselection based on membrane perforation size (<10 mm: small-moderate/≥10 mm: large) and biotype (BT; thick BT/thin BT) into four subgroups (SMP1: thick BT/small-moderate; SMP2: thin BT/small-moderate; SMP3: thick BT/large; SMP4: thin BT/large). For the various subgroups, patient- and surgery-related/anatomic risk factors affecting SMP were evaluated and the scope of sinus membrane repair (SSMR) mechanisms rated with 1 (easy) to 5 (complex) was compared. RESULTS: For 103/434 SMP (27.6%) in 93/334 patients (30.8%) the prevalence of various forms of SMP differed significantly (p < 0.001) among the four subgroups. SMP4 with a prevalence of 45.6% (n = 47) was the most frequent type, while SMP3 had low prevalence with 4.85% (n = 5). Small/moderate SMPs with thick (SMP1: n = 26) or thin BT (SMP2: n = 23) were seen in 26.2% and 23.3%, respectively. Univariate analysis showed significant differences between subgroups with large perforations (SMP3/SMP4) and those with small/moderate perforations (SMP1/SMP2) regarding anatomic risk factors such as residual ridge height (p = 0.023) and history of previous oral surgical interventions (OSI; p = 0.026). Most evidently, multivariate analysis showed that induction of large SMP with thin biotype (SMP4) was significantly affected by the presence of sinus septa (p < 0.022, OR: 2.415), reduced residual ridge height (p < 0.001, OR: 1.842), and previous OSI (p < 0.001, OR: 4.545). SSMR differed significantly (p < 0.001) between SMP4 (4.62 ± 0.49) and the subgroups SMP1 (1.11 ± 0.32), SMP2 (1.08 ± 028), and SMP3 (2.2 ± 0.55). CONCLUSION: The most frequently found type of SMP had characteristics of thin biotype and large size associated with risk factors such as sinus septa, reduced residual ridge, and previous surgical interventions and required challenging repair mechanisms assessing clinical impact.

Dental implants in patients with rheumatoid arthritis: clinical outcome and peri-implant findings.

PURPOSE: Implant prosthodontic treatment outcomes for patients suffering from autoimmune rheumatoid arthritis (RA) with or without concomitant connective tissue diseases (CTD) were evaluated. MATERIAL AND METHODS: Thirty-four female patients' (25 isolated RA; nine RA+CTD) implant survival/success rate, peri-implant conditions (marginal bone loss, pocket depth, plaque index, gingiva index and bleeding index) and incidence of prosthodontic maintenance were retrospectively evaluated. RESULTS: Implants evaluated presented a high implant survival (100%) and a 3.5-year success (93.8%) rate during the follow-up programme (mean 47.6 month) without difference between isolated RA (94.6%) and RA and concomitant CTD (92.3%), respectively. In isolated RA, acceptable marginal bone resorption (mean: 2.1 mm; SD: 0.5 mm), pocket depth (mean: 2.8 mm; SD:3.2 mm) and healthy soft-tissue conditions (plaque/bleeding/gingiva index Grade 0 in 80%) were noticed. However, patients with RA+CTD presented increased bone resorption (mean: 3.1 mm; SD: 0.7 mm) and more vulnerable soft-tissue conditions (higher bleeding index) differing significantly to patients with isolated RA (p<0.01). Peri-implant parameters were significantly influenced by the patients' underlying disease (RA, RA+CTD; Kruskal-Wallis test, Jonckheere-Terpstra test). CONCLUSIONS: In contrast to isolated RA, in RA patients with concomitant CTD, differences in the peri-implant parameters such as pronounced marginal bone resorption and bleeding may be anticipated and appear to be significantly influenced by the patients' underlying disease.

Removable implant-prosthodontic rehabilitation of the edentulous mandible: five-year results of different prosthetic anchorage concepts.

PURPOSE: The present study evaluated implant and peri-implant outcomes as well as prosthodontic maintenance efforts for implant/bar-supported mandibular prostheses with different prosthesis anchorage systems. MATERIALS AND METHODS: Seventy-six patients who received two or four interforaminal implants were assigned to one of three different bar designs and subsequently to different prosthesis supporting systems. Forty-nine patients received implants and a mucosa-supported implant-retained overdenture (OD) with an ovoid bar (two implants; design 1) or multiple ovoid bars (four implants; design 2). Twenty-seven patients received four implants and a rigid implant-supported prosthesis (ISP) with a milled bar (design 3). Implant survival, peri-implant parameters (marginal bone resorption, pocket depth, and plaque, bleeding, gingival, and calculus indices), and postinsertion prosthodontic maintenance were followed over a 5-year period and compared among the different retention modalities. At the most recent follow-up examination, subjective patient satisfaction was additionally evaluated using a simplified scoring system (ranging from 1 = not satisfactory to 5 = excellent). RESULTS: Implant survival rates (100%) and all peri-implant parameters evaluated showed no differences among the three designs used for implant prosthesis anchorage. Prosthodontic maintenance did not differ between the different ODs (OD design 1: average of 1.04 maintenance visits/year/patient; OD design 2: 1.2 maintenance visits/year/patient), but it was significantly lower for the dentures that were rigidly stabilized with milled bars (ISP: 0.37 maintenance visits/year/patient). A high subjective satisfaction rate (range: 4.5 to 5.0) was registered at the final examination, without any differences among the designs used. CONCLUSIONS: Rigid anchorage with milled bars on four-implant prostheses combined with a metal-reinforced framework showed a lower extent of prosthodontic maintenance issues than round bars on two- or four-implant overdentures with resilient denture stabilization. Nevertheless, implants and peri-implant structures were not negatively affected by either resilient or rigid anchorage mechanisms.

Clinical outcome of root-shaped dental implants of various diameters: 5-year results.

PURPOSE: The aim of this retrospective study was to evaluate the long-term survival and success rates of screw-type root-shaped (Camlog) implants of various diameters and their implant-prosthodontic reconstructions for more than 5 years of clinical use. MATERIALS AND METHODS: A retrospective study of patients receiving root-shaped screw-type dental implants placed between May 2001 and July 2003 was conducted. The cumulative implant survival and success rates and peri-implant conditions (marginal bone loss, pocket depth, Plaque Index, Gingival Index, Bleeding Index) as well as the prosthodontic maintenance requirements were evaluated. RESULTS: In all, 541 implants (3.8 mm: 237 implants; 4.3 mm: 211 implants, 5/6 mm: 93 implants) were placed and restored for implant prosthodontic rehabilitation in 216 patients (134 women, 82 men; mean age 54.3 +/- 9.1 years). Of the original 216 patients enrolled, 198 (91.6%; 510/541 implants [94.2%]) were available for a follow-up evaluation after 5 to 7 years (mean follow-up, 68.8 +/- 7.4 months). The overall cumulative 5-year survival and success rates were 98.3% and 97.3%, respectively. A failure rate of 3.7% (9/237) was seen for 3.8-mm-diameter implants; the corresponding figures for the 4.3-mm and wide-diameter (5.0/6.0-mm) implants were 1.4% (3/211) and 1.0% (1/93), respectively. For implants classified as successful, the average peri-implant marginal bone resorption value was 1.8 +/- 0.4 mm, with no differences among the different implant diameters evaluated. Peri-implant soft tissue conditions such as plaque, bleeding, and pocket depth were also satisfactory. All prostheses were functional throughout the observation period, with no fractures of implants, abutments, or screws. Abutment screw (4.5%) or isolated crown loosening (9.8%) for single-tooth restorations requiring recementation, retightening of screws, and adaptation of removable prostheses were the most frequent prosthodontic maintenance needs. CONCLUSION: The root-shaped implants and the associated prosthetic constructions used in this study showed excellent survival and success rates.