Is alveolar ridge preservation an overtreatment?

The morphology and dimensions of the postextraction alveolar ridge are important for the surgical and restorative phases of implant treatment. Adequate new bone formation and preservation of alveolar ridge dimensions following extraction will facilitate installation of the implant in a restorative position, while preservation of soft tissue contour and volume is essential for an aesthetic and implant-supported restoration with healthy peri-implant tissues. Alveolar ridge preservation (ARP) refers to any procedure that aims to: (i) limit dimensional changes in the alveolar ridge after extraction facilitating implant placement without additional extensive bone and soft tissue augmentation procedures (ii) promote new bone formation in the healing alveolus, and (iii) promote soft tissue healing at the entrance of the alveolus and preserve the alveolar ridge contour. Although ARP is a clinically validated and safe approach, in certain clinical scenarios, the additional clinical benefit of ARP over unassisted socket healing has been debated and it appears that for some clinicians may represent an overtreatment. The aim of this critical review was to discuss the evidence pertaining to the four key objectives of ARP and to determine where ARP can lead to favorable outcomes when compared to unassisted socket healing.

13-year follow-up of a randomized controlled study on zirconia and titanium abutments.

OBJECTIVES: To assess survival rates and compare technical, biological, and esthetic outcomes of customized zirconia and titanium abutments at 13 years post loading. MATERIALS AND METHODS: Initially, 22 patients with 40 implants in posterior regions were included. The sites were randomly assigned to 20 customized zirconia abutments with cemented all ceramic crowns (ACC) and 20 customized titanium abutments with cemented metal ceramic crowns (MCC). At a mean follow-up of 13.4 years, patients were examined and implants/restorations assessed for survival and technical complications, as well as biological and esthetic outcomes (pocket probing depth [PPD], bleeding on probing [BOP], plaque control record [PCR], bone level [BL], papilla index [PAP], mucosal thickness, and recession (distance of the margo mucosae [MM]/margo gingivae MG)). Descriptive analyses were performed for all outcome measures. RESULTS: Fifteen patients with 21 abutments (13 zirconia, 8 titanium) were examined at 13 years. The drop-out rate was 25% (patient level). The technical survival rate of the abutments was 100%. The survival rate on the restorative level (crowns) was 100%. The assessed biological outcomes (PPD, PCR, BOP, BL) and esthetic outcomes (MG, PAP) were similar. CONCLUSIONS: Zirconia and titanium abutments supporting single implant-borne restorations rendered a high survival rate and minimal differences in terms of technical, biological, and esthetic outcomes at 13 years of follow-up.

The 3D emergence profile on implant-supported restorations: A method for evaluating restorative angles.

STATEMENT OF PROBLEM: Emerging evidence indicates that the emergence profile and subsequent restorative angle play a crucial role in clinical outcomes and can potentially affect the development and progression of peri-implant diseases. However, the traditional evaluation of the emergence profile and angle has been limited to mesial and distal sites using periapical x-rays, without considering the buccal sites. PURPOSE: To describe a novel 3D method to estimate the emergence profile and restorative angles around single implant-supported crowns including buccal sites. MATERIALS AND METHODS: A total of 30 implant-supported crowns (11 molars, 8 premolars, 8 central incisors and 1 canine) were extra-orally scanned using an intraoral scanner and the STL files produced were imported into a 3D software. The crown/abutment interface of each crown was delineated, and apico-coronal lines were automatically drawn following the shape of the crown. Three reference points were defined on the apico-coronal lines at the transition edge of the biological (BC) and the esthetic zone (EC) and the resulting angles were then calculated. The reliability of the measurements (2D and 3D) were assessed using the intraclass correlation coefficient (ICC). RESULTS: In anterior restorations, the mean angle of the esthetic zone amounted to 162 ± 14° at mesial sites, to 140 ± 10° at buccal sites and to 163 ± 11° at distal sites. The corresponding angles at the biological zones, amounted to 155 ± 13° at mesial sites, 139 ± 15° at buccal sites and 157 ± 5° at distal sites. In posterior restorations, the mean angle of the esthetic zone amounted to 162 ± 12° at mesial sites, to 157 ± 13 at buccal sites and to 162 ± 11 at distal sites. The corresponding angles at the biological zone, amounted to 158 ± 8 at mesial sites, 150 ± 15° at buccal sites and 156 ± 10 at distal sites. The ICC for all measurements ranged between 0.77 and 0.99 indicating a good intra-examiner reliability. CONCLUSION: Within the limitations of the present study, the 3D analysis seems to be a reliable and applicable method for the quantitative evaluation of the emergence profile in daily practice. Future randomized clinical trials are needed to assess whether a 3D analysis with the ensuing the emergence profile serves as a predictor for clinical outcomes. CLINICAL SIGNIFICANCE: The development and implementation of a 3D workflow will provide technicians and dentists with the ability to assess the restorative angle of implant-supported restorations during the provisional phase and the final restoration. This approach may help achieve an aesthetically pleasing restoration while minimizing potential clinical complications.

The L-shape technique in guided bone regeneration with simultaneous implant placement in the esthetic zone: A step-by-step protocol and a 2-14 year retrospective study.

OBJECTIVES: To describe the methodology of the "L-shape" technique in guided bone regeneration (GBR) with simultaneous implant placement and report on the clinical, esthetic, and patient satisfaction outcomes up to 14 years of follow-up. MATERIAL AND METHODS: Fourteen patients treated with the "L-shape" technique were included in this retrospective study. The L-shape technique was performed by trimming and placing a soft-type bone block made of deproteinized bovine bone mineral with 10% collagen at the buccal-occlusal aspect of the dental implant. The remaining gaps were filled with deproteinized bovine bone mineral granules and the augmented area was covered with a collagen membrane. The following parameters were recorded:  probing depth (PD), bleeding on probing (BOP), plaque index (PI), keratinized tissue width (KT) and marginal bone level (MBL). Esthetic outcomes were assessed according to the pink esthetic score (PES) and the white esthetic score (WES). Patient satisfaction was evaluated by means of a numerical rating scale (0-10). The stability of each augmented site was assessed by measuring the volumetric changes between baseline (crown delivery) and the respective follow-up. RESULTS: A total of 13 maxillary incisors and one maxillary canine in 14 patients were included. The mean follow-up period was 7.7 ± 3.8 years. PES values amounted to 10.7 ± 3.3 and WES to 8.8 ± 1.4. Patient satisfaction reached 9.4 ± 0.8. Mean PD at implant sites were 2.7 ± 0.7 mm while BOP amounted to 15.0 ± 0.2% and Pl to 5.0 ± 0.0%. Volumetric analyses revealed minimal changes at the augmented sites irrespective of the region of interest. Radiographic MBL remained relatively stable. CONCLUSIONS: Within the limitation of the present study the L-shape augmentation procedure seems to be a reliable technique when performing GBR with simultaneous implant placement in the esthetic zone. Outcomes encompassed stable clinical and esthetic results accompanied by high levels of patient satisfaction. Future randomized controlled trials are warranted to confirm possible benefits of the L-shape technique over traditional approaches. CLINICAL SIGNIFICANCE: The L-shape appears to be a simple yet promising technique in GBR with simultaneous implant placement that can easily be translated into clinical practice.

Peri-implant tissue changes at sites treated with alveolar ridge preservation in the aesthetic zone: Twenty-two months follow-up of a randomized clinical trial.

AIM: To compare tissue changes at implant sites previously treated with two biomaterials for alveolar ridge preservation (ARP) in the aesthetic zone, 1 year after restoration. MATERIALS AND METHODS: Sixty-six participants were treated with ARP using demineralized bovine bone mineral (DBBM) or DBBM +10% of collagen (DBBM-C), both covered with a collagen matrix (CM). Dental implants were placed, and definitive crowns were installed. Silicon impressions were taken before tooth extraction (T0), 2 weeks after crown insertion (T1) and 1 year after restoration (T2). Mid-facial mucosal level change (MLC), soft tissue thickness changes (TT), and marginal bone loss (MBL) were analysed using inter-group comparisons. RESULTS: Fifty-four participants were included in the analysis. The mid-facial level change between T0-T1 and T1-T2 showed no statistical difference between DBBM and DBBM-C. Between T0 and T1 for soft tissue thickness, DBBM performed significantly better at 3 and 5 mm below the mucosal margin. From T1 to T2, no significant differences between groups were found at any level for soft tissue thickness and MBL. CONCLUSION: At the aesthetic zone, advanced recession from tooth extraction to crown placement can be expected at sites treated with ARP regardless of biomaterial used. However, after crown insertion, tissue stability can be predicted.

Clinical outcomes of all-ceramic single crowns and fixed dental prostheses supported by ceramic implants: A systematic review and meta-analyses.

OBJECTIVE: To analyze the clinical outcomes of all-ceramic single crowns (SCs) and fixed dental prostheses (FDPs) supported by ceramic implants. MATERIALS AND METHODS: Based on a focused question and customized PICO framework, electronic (Medline/EMBASE/Cochrane) and manual searches for studies reporting the clinical outcomes of all-ceramic SCs and FDPs supported by ceramic implants ≥12 months were performed. The primary outcomes were reconstruction survival and the chipping proportion. The secondary outcomes were implant survival, technical complications, and patient-related outcome measurements. Meta-analyses were performed after 1, 2, and 5 years using random-effect meta-analyses. RESULTS: Eight of the 1,403 initially screened titles and 55 full texts were included. Five reported on monolithic lithium disilicate (LS2) SCs, one on veneered zirconia SCs, and two on veneered zirconia SCs and FDPs, which reported all on cement-retained reconstructions (mean observation: 12.0-61.0 months). Meta-analyses estimated a 5-year survival rate of 94% (95% confidence interval [CI]: 82%-100%) for overall implant survival. Reconstruction survival proportions after 5 years were: monolithic LS2, 100% (95%CI: 95%-100%); veneered zirconia SCs, 89% (95%CI: 62%-100%); and veneered zirconia FDPs 94% (95%CI: 81%-100%). The chipping proportion after 5 years was: monolithic LS2, 2% (95%CI: 0%-11%); veneered zirconia SCs, 38% (95%CI: 24%-54%); and veneered zirconia FDPs, 57% (95%CI: 38%-76%). Further outcomes were summarized descriptively. CONCLUSIONS: Due to the limited data available, only tendencies could be identified. All-ceramic reconstructions supported by ceramic implants demonstrated promising survival rates after mid-term observation. However, high chipping proportions of veneered zirconia SCs and, particularly, FDPs diminished the overall outcome. Monolithic LS2 demonstrated fewer clinical complications. Monolithic reconstructions could be a valid treatment option for ceramic implants.

Accuracy of computer-assisted, template-guided implant placement compared with conventional implant placement by hand-An in vitro study.

OBJECTIVES: To compare free-hand to computer-assisted implant planning and placement (CAIPP) regarding planned to achieved implant position. MATERIAL AND METHODS: Forty-eight cast/bone models were mounted in mannequin heads. On each side, a tooth gap of different sizes was created. In the test group (T), study implants were placed using a CAD-CAM guide based on virtual planning. In the control (C), free-hand implant placement was performed. After CBCT scanning, the implant position was compared with the planned position. Descriptive statistics were applied, and ANOVA was used to identify differences between groups and gaps. (p < .05). RESULTS: In C, mean lateral deviations at the implant base amounted to 0.7 mm (max. 1.8) (large gap) and 0.49 mm (1.22) (small gap). In T, 0.18 mm (0.49) and 0.24 mm (0.52) were recorded. At the apex, 0.77 mm (2.04) (large gap) and 0.51 mm (1.24) (small gap) were measured in C, and 0.31 mm (0.83)/0.34 mm (0.93) in T. Mean vertical deviations in C measured 0.46 mm (1.26) (large gap) and 0.45 mm (1.7) (small gap). In T, 0.14 mm (0.44) and 0.28 mm (0.78) were recorded. Mean angular deviations of 1.7° (3.2°) were observed in C (large gap) and 1.36° (2.1°) (small gap). In T, mean values were 1.57° (3.3°) and 1.32° (3.4°). Lateral and vertical deviations were significantly different between groups (not gaps), angular between gaps (not groups). CONCLUSIONS: CAIPP protocols showed smaller deviations irrespective of the size of the tooth gap. In C, the gap size had an influence on the error in angulation only.

Soft tissue contour and radiographic evaluation of ridge preservation in early implant placement: A randomized controlled clinical trial.

OBJECTIVES: To compare two ridge preservation techniques and spontaneous healing in terms of hard and soft tissue changes 2 months after tooth extraction. MATERIAL AND METHODS: The study was designed as a randomized controlled trial and included 75 patients. After single tooth extraction in the maxillary incisor/premolar area, patients were randomly allocated to one of the following groups: (a) ridge preservation with a xenogeneic bone substitute covered with a collagen matrix (CM-group), (b) ridge preservation with a xenogeneic bone substitute covered with a free palatal graft (PG-group) or (c) spontaneous healing (control). Eight weeks after tooth extraction, implants were placed and clinical, profilometric and radiographic evaluations were performed. In addition, the need for further guided bone regeneration (GBR) at implant placement was assessed. The differences between the treatment groups were compared with the One-way ANOVA or Kruskal-Wallis test with the corresponding post hoc analysis. The proportions of the categorical parameters were compared with the Fisher´s exact test. RESULTS: Seventy-five patients underwent early implant placement 8 weeks after tooth extraction and were evaluated. CM-group (-0.9 SD 0.6 mm) and PG-group (-1.0 SD 0.8 mm) showed less horizontal bone resorption compared to the control group (-3.2 SD 2.1 mm) (p < .001). Moreover, the necessity of GBR at implant placement was significantly less in CM-group (32%) and PG-group (24%) when compared to control group (72%) (p = .001). Patients in CM-group experienced less pain than PG-group, one week after tooth extraction (p = .042). No significant differences were found regarding graft evaluation, post-operative complications, and soft tissue contour. CONCLUSIONS: Ridge preservation using a xenogeneic bone substitute covered with a collagen matrix or a palatal graft, results in less bone resorption and fewer GBR procedures at early implant placement compared to spontaneous healing.

Comparison of a polyethylene glycol membrane and a collagen membrane for the treatment of bone dehiscence defects at bone level implants-A prospective, randomized, controlled, multicenter clinical trial.

OBJECTIVES: The aim of the present randomized, controlled clinical multicenter trial was to compare a polyethylene glycol (PEG) and a native collagen membrane (BG) for simultaneous guided bone regeneration at bony dehiscence-type defects around bone level titanium implants. MATERIAL AND METHODS: The study enrolled 117 patients requiring implant treatment in the posterior maxilla or mandible with expected buccal bony dehiscence-type defects at the placed titanium implants. According to a parallel groups design, defects were filled with a synthetic bone filler and randomly assigned to either PEG or BG membrane. As primary parameter, the relative vertical bone fill was assessed at baseline and at re-entry after 6 months of healing. As secondary parameters, the marginal bone level (MBL) was assessed radiographically and soft tissue conditions were recorded up to 18 months postloading. RESULTS: Both groups showed comparable vertical bone fill revealing a relative change in defect height of 59.7% (PEG) and 64.4% (BG). The absolute mean reduction in defect size was 2.5 mm in the PEG group and 3.2 mm in the BG group. Although both groups revealed a statistically significant mean defect reduction (p < .001), a comparison between the two groups did not show statistical significances. The non-inferiority test with inferiority limit of -5% could not be rejected, based on the 90% confidence interval of the differences of the two means with lower limit -15.4%. After 18 months, an MBL increase of 0.45 ± 0.43 mm in the PEG group and 0.41 ± 0.81 mm in the BG group was detected (p < .001). Soft tissue complications were observed in both groups without showing statistical significance. CONCLUSIONS: Both membranes supported bone regeneration at dehiscence-type defects and obtained vertical bone fill with a relative change in defect height of 59.7% (PEG) and 64.4% (BG); however, the non-inferiority of PEG could not be shown.

Conventional versus flap-protected free gingival graft: a multicenter randomized clinical trial.

The purpose of this study was to compare the outcomes of a modified gingival graft technique, in which the released flap is positioned and sutured over the graft, with the conventional free gingival graft (FGG) procedure, when both are used for gingival augmentation. A 12-month, multicenter parallel randomized controlled trial was conducted. Subjects with buccal RT2 gingival recessions and keratinized tissue width (KTW) < 2 mm in at least one mandibular incisor were randomized to control group (n = 20; conventional FGG) or test group (n = 20; modified FGG; flap sutured over FGG using sling sutures). The primary outcome (KTW) was measured at baseline and after 3, 6 and 12 months, as was keratinized tissue thickness (KTT). Postoperative pain (POP) and analgesic intake were also recorded. Both techniques promoted a significant increase in KTW and KTT when compared to baseline (p < 0.05) with no significant differences between groups (KTW change of 6.1±1.5 mm and 5.4±1.6 mm, for control and test, respectively; p=0.16). However, test group patients reported less POP after 7 days and used less analgesic medication than control group patients (p < 0.05). We concluded that the modified FGG was comparable to conventional FGG in augmenting keratinized tissue width and thickness at mandibular incisors, but resulted in less patient morbidity.

Simultaneous Assessment of Soft and Hard Tissue Behaviors After Alveolar Ridge Preservation Using Bone Substitutes.

This study aimed to simultaneously assess hard and soft tissues alterations and their proportions after alveolar ridge preservation (ARP). Participants (n = 65) who were previously enrolled in a clinical trial investigating ARP healing were selected. The CBCT DICOM (Digital Imaging and Communications in Medicine) and the cast STL (stereolithographic) files of each subject were imported, segmented, and superimposed. A cross-section view of the superimposed image presented the outlines from each DICOM and STL file. The center of preserved ridge was selected in the superimposed image and used to draw the reference lines to realize the measurements. Horizontal linear measurements determined ridge width (RW) and its respective hard/soft tissue proportion (H:S) at 1, 3, 5, and 7 mm below the buccal bone crest immediately after ARP and at the 4-month follow-up. At 1 mm, the baseline RW was 11.6 mm and reduced to 10 mm after 4 months. The baseline H:S was 65%:35% and was 43%:57% at the 4-month follow-up. Considering only the buccal half of the ridge, baseline H:S was 77%:23%, while after 4 months it shifted to 58%:42%. A similar pattern was observed at 3, 5, and 7 mm but with decreased resorption degree. The present study showed that hard tissue is mostly responsible for RW loss after healing, especially in the first 3 mm below the buccal bone crest. Soft tissue partially compensated for the hard tissue shrinkage, gaining thickness in the analyzed areas.

Randomized-controlled clinical trial of customized zirconia and titanium implant abutments for single-tooth implants in canine and posterior regions: 3-year results.

OBJECTIVES: The aim was to test whether or not zirconia abutments exhibit the same survival and technical/biological outcome as titanium abutments. MATERIAL AND METHODS: Twenty-two patients receiving 40 single-tooth implants in canine and posterior regions were included. The implant sites were randomly assigned to 20 zirconia and 20 titanium abutments. All-ceramic and metal-ceramic crowns were fabricated. At baseline, 6, 12 and 36 months, the reconstructions were examined for technical and biological problems. Probing pocket depth (PPD), plaque control record (PCR) and bleeding on probing (BOP) were assessed at abutments (test) and analogous contralateral teeth (control). Standardized radiographs of the implants were made and the bone level (BL) was measured referring to the implant shoulder on mesial (mBL) and distal sides (dBL). The difference of color (DeltaE) of the peri-implant mucosa and the gingiva of control teeth was assessed with a spectrophotometer. The data were statistically analyzed with Mann-Whitney Rank and Student's unpaired t-tests. RESULTS: Eighteen patients with 18 zirconia and 10 titanium abutments were examined at a mean follow-up of 36 months (range 31.5-53.3 months). No fracture of an abutment or loss of a reconstruction was found. Hence, both exhibited 100% survival. At two metal-ceramic crowns supported by titanium abutments chipping of the veneering ceramic occurred. No difference of the biological outcome of zirconia and titanium abutments was observed: PPD (meanPPD(ZrO(2)) 3.2 +/- 1 mm, mPPD(Ti) 3.4 +/- 0.5 mm), PCR (mPCR(ZrO(2)) 0.1 +/- 0.2, mPCR(Ti) 0.1 +/- 0.2) and BOP (mBOP(ZrO(2)) 0.4 +/- 0.4, mBOP(Ti) 0.2 +/- 0.3). Furthermore, the BL was similar at implants supporting zirconia and titanium abutments (mBL(ZrO(2)) 1.7 +/- 1, dBL(ZrO(2)) 1.6 +/- 1; mBL(Ti) 2 +/- 1, dBL(Ti) 2.1 +/- 1). Both, zirconia and titanium abutments induced a similar amount of discoloration of the mucosa compared with the gingiva at natural teeth (DeltaE(ZrO(2)) 9.3 +/- 3.8, DeltaE(Ti) 6.8 +/- 3.8). CONCLUSIONS: At 3 years, zirconia and titanium abutments exhibited same survival and technical, biological and esthetical outcomes.

Randomized controlled clinical trial of customized zirconia and titanium implant abutments for canine and posterior single-tooth implant reconstructions: preliminary results at 1 year of function.

OBJECTIVES: The aim of this study was to test whether or not customized zirconia abutments exhibit the same survival rates in canine and posterior regions as titanium abutments, and to compare the esthetic result of the two abutment types. MATERIAL AND METHODS: Twenty-two patients with 40 implants in posterior regions were included and the implant sites were randomly assigned to 20 customized zirconia and 20 customized titanium abutments. All-ceramic (AC) and metal-ceramic (MC) crowns were fabricated. In all except two cases, the crowns were cemented on the abutments using resin or glass-ionomer cements. Two zirconia reconstructions were screw retained. At baseline, 6 and 12 months, the reconstructions were examined for technical and biological problems. Probing pocket depth (PPD), plaque (Pl) and bleeding on probing (BOP) were assessed and compared with natural control teeth. Furthermore, the difference of color (DeltaE) of the peri-implant mucosa and the gingiva of control teeth was evaluated by means of a spectrophotometer (Spectroshade). The data were analyzed with Student's unpaired t-test, ANOVA and regression analyses. RESULTS: Twenty patients with 19 zirconia and 12 titanium abutments were examined at a mean follow-up of 12.6+/-2.7 months. The survival rate for reconstructions and abutments was 100%. No technical or biological problems were found at the test and control sites. Two chippings (16.7%) occurred at crowns supported by titanium abutments. No difference was found regarding PPD (meanPPD(ZrO2) 3.4+/-0.7 mm, mPPD(Ti) 3.3+/-0.6 mm), Pl (mPl(ZrO2) 0.2+/-0.3, mPl(Ti) 0.1+/-1.8) and BOP (mBOP(ZrO2) 60+/-30%, mBOP(Ti) 30+/-40%) between the two groups. Both crowns on zirconia and titanium abutments induced a similar amount of discoloration of the soft tissue compared with the gingiva at natural teeth (DeltaE(ZrO2) 8.1+/-3.9, DeltaE(Ti) 7.8+/-4.3). CONCLUSIONS: At 1 year, zirconia abutments exhibited the same survival and a similar esthetic outcome as titanium abutments.

In vitro study of the influence of the type of connection on the fracture load of zirconia abutments with internal and external implant-abutment connections.

PURPOSE: To determine whether zirconia abutments with an internal connection exhibit similar fracture load as zirconia abutments with an external connection. MATERIALS AND METHODS: The following zirconia abutments were divided into four groups of 20 each: StraumannCARES abutments on Straumann implants (group A), Procera abutments on Branemark implants (group B), Procera abutments on NobelReplace implants (group C), and Zirabut SynOcta prototype abutments on Straumann implants (group D). The abutments were fixed on their respective implants either internally via a secondary abutment (A) or a metallic coupling (C) (two-piece) or directly externally (B) and internally (D) (one-piece). In each group, 10 abutments were left unrestored (A1 to D1). Ten received glass-ceramic crowns (A2 to D2). Static loading was performed according to the ISO norm 14801 until failure. The bending moment was calculated for comparison of the groups and subjected to statistical analysis (Student t test). RESULTS: The mean bending moments of the unrestored abutments were 371.5 +/- 142.3 Ncm (A1), 276.5 +/- 47.6 Ncm (B1), 434.9 +/- 124.8 Ncm (C1), and 182.5 +/- 136.5 Ncm (D1). Two-piece internally connected abutments exhibited higher bending moments than one-piece internally (C1 versus D1 P = .003, A1 versus D1 P = .03) or externally (C1 versus B1 P = .004) connected abutments. The groups with restorations did not show different bending moments than those without restorations. The mean bending moments of the restored abutments were 283.3 +/- 44.8 Ncm (A2), 291.5 +/- 31.7 Ncm (B2), 351.5 +/- 58 Ncm (C2), and 184.3 +/- 77.7 Ncm (D2). Group C2 exhibited the highest bending moment (P < .05). Internally connected one-piece abutments (D2) were weaker than all other groups (D2 versus A2 P = .002; D2 versus B2 P = .001; D2 versus C2 P = .0003). CONCLUSIONS: The type of connection significantly influenced the strength of zirconia abutments. Superior strength was achieved by means of internal connection via a secondary metallic component.

Single-Tooth Replacement Using Dental Implants Supporting All-Ceramic and Metal-Based Reconstructions: Results at 18 Months of Loading.

The aim of this study was to compare customized zirconia and titanium abutments with respect to survival rates and technical, biologic, and esthetic outcomes. A total of 28 patients with single implants were randomly assigned to 12 customized zirconia (test, AC) and 16 customized titanium (control, MC) abutments. Technical, biologic, and esthetic outcomes were assessed after a mean follow-up time of 18 months. No biologic complications were observed, and no statistical difference for the bone-to-implant distance was found at 18 months (AC -0.05 ± 0.51 mm vs MC -0.28 ± 0.77 mm; P = .40). A similar discoloration of the peri-implant mucosa was observed (ΔEAC 9.6 ± 5.4, ΔEMC 7.6 ± 5.3; P = .46). The mean papilla score values evaluation presented no statistically significant differences between the test and control groups (AC 2.07 ± 0.94, MC 1.96 ± 0.84). At 18 months, reconstructions based on zirconia and titanium abutments exhibited similar survival rates and similar clinical outcomes.

Tissue integration of zirconia and titanium implants with and without buccal dehiscence defects.

PURPOSE: The purpose of the present study was to validate an experimental model for assessing tissue integration of titanium and zirconia implants with and without buccal dehiscence defects. METHODS: In 3 dogs, 5 implants were randomly placed on both sides of the mandibles: 1) Z1: a zirconia implant (modified surface) within the bony housing, 2) Z2: a zirconia implant (standard surface) within the bony housing, 3) T: a titanium implant within the bony housing, 4) Z1_D: a Z1 implant placed with a buccal bone dehiscence defect (3 mm), and 5) T_D: a titanium implant placed with a buccal bone dehiscence defect (3 mm). The healing times were 2 weeks (one side of the mandible) and 6 weeks (the opposite side). RESULTS: The dimensions of the peri-implant soft tissue varied depending on the implant and the healing time. The level of the mucosal margin was located more apically at 6 weeks than at 2 weeks in all groups, except group T. The presence of a buccal dehiscence defect did not result in a decrease in the overall soft tissue dimensions between 2 and 6 weeks (4.80±1.31 and 4.3 mm in group Z1_D, and 4.47±1.06 and 4.5±1.37 mm in group T_D, respectively). The bone-to-implant contact (BIC) values were highest in group Z1 at both time points (34.15%±21.23% at 2 weeks, 84.08%±1.33% at 6 weeks). The buccal dehiscence defects in groups Z1_D and T_D showed no further bone loss at 6 weeks compared to 2 weeks. CONCLUSIONS: The modified surface of Z1 demonstrated higher BIC values than the surface of Z2. There were minimal differences in the mucosal margin between 2 and 6 weeks in the presence of a dehiscence defect. The present model can serve as a useful tool for studying peri-implant dehiscence defects at the hard and soft tissue levels.

Maxillary sinus floor pneumatization and alveolar ridge resorption after tooth loss: a cross-sectional study.

This is a cross-sectional study that aimed to estimate maxillary sinus floor (MSF) pneumatization in single missing tooth of posterior maxilla, by using cone-beam computed tomography (CBCT). CBCT images were analyzed bilaterally and divided into 2 groups: edentulous site (EdS) - edentulous single region of upper second premolar, first or second molars; Tooth site (TS) - contralateral region homologous to the EdS region, with tooth present. Variables evaluated were: sinus height (SH), estimated sinus pneumatization (eSP: ∆ EdS - TS), healed ridge height (HR) and presence of localized sinus pneumatization (LSP) in molars teeth at TS. HR were categorized according to therapeutic option for posterior maxilla. 183 CBCT scans were included and it was observed that EdS presented a higher SH than the TS (p < 0.001) showing an eSP of 0.9 ± 2.93 mm. First molars presented the highest SH for both sides, although significant differences were detected when compared to second molars. First molars were mostly affected by LSP at TS (36 out of 43). Individuals with LSP at TS presented lower HR than the ones without LSP (p < 0.05). 54% of the cases presenting LSP obtained HR < 5 mm, which indicates sinus lift surgery. The present study showed that tooth loss in posterior maxilla favors sinus pneumatization and the identification of LSP at molar roots seems to indicate a greater necessity for sinus lift surgeries.

Conventional versus flap-protected free gingival graft: a multicenter randomized clinical trial

Abstract The purpose of this study was to compare the outcomes of a modified gingival graft technique, in which the released flap is positioned and sutured over the graft, with the conventional free gingival graft (FGG) procedure, when both are used for gingival augmentation. A 12-month, multicenter parallel randomized controlled trial was conducted. Subjects with buccal RT2 gingival recessions and keratinized tissue width (KTW) < 2 mm in at least one mandibular incisor were randomized to control group (n = 20; conventional FGG) or test group (n = 20; modified FGG; flap sutured over FGG using sling sutures). The primary outcome (KTW) was measured at baseline and after 3, 6 and 12 months, as was keratinized tissue thickness (KTT). Postoperative pain (POP) and analgesic intake were also recorded. Both techniques promoted a significant increase in KTW and KTT when compared to baseline (p < 0.05) with no significant differences between groups (KTW change of 6.1±1.5 mm and 5.4±1.6 mm, for control and test, respectively; p=0.16). However, test group patients reported less POP after 7 days and used less analgesic medication than control group patients (p < 0.05). We concluded that the modified FGG was comparable to conventional FGG in augmenting keratinized tissue width and thickness at mandibular incisors, but resulted in less patient morbidity.

Maxillary sinus floor pneumatization and alveolar ridge resorption after tooth loss: a cross-sectional study

Abstract This is a cross-sectional study that aimed to estimate maxillary sinus floor (MSF) pneumatization in single missing tooth of posterior maxilla, by using cone-beam computed tomography (CBCT). CBCT images were analyzed bilaterally and divided into 2 groups: edentulous site (EdS) - edentulous single region of upper second premolar, first or second molars; Tooth site (TS) - contralateral region homologous to the EdS region, with tooth present. Variables evaluated were: sinus height (SH), estimated sinus pneumatization (eSP: ∆ EdS - TS), healed ridge height (HR) and presence of localized sinus pneumatization (LSP) in molars teeth at TS. HR were categorized according to therapeutic option for posterior maxilla. 183 CBCT scans were included and it was observed that EdS presented a higher SH than the TS (p < 0.001) showing an eSP of 0.9 ± 2.93 mm. First molars presented the highest SH for both sides, although significant differences were detected when compared to second molars. First molars were mostly affected by LSP at TS (36 out of 43). Individuals with LSP at TS presented lower HR than the ones without LSP (p < 0.05). 54% of the cases presenting LSP obtained HR < 5 mm, which indicates sinus lift surgery. The present study showed that tooth loss in posterior maxilla favors sinus pneumatization and the identification of LSP at molar roots seems to indicate a greater necessity for sinus lift surgeries.

Use of a new cross-linked collagen membrane for the treatment of peri-implant dehiscence defects: a randomised controlled double-blinded clinical trial.

PURPOSE: The aim of this randomised controlled double-blinded clinical trial was to determine the efficacy of a new cross-linked membrane (VN) in guided bone regeneration (GBR) around exposed dental implants compared to a native collagen membrane (BG). MATERIAL AND METHODS: A total of 16 patients in need of implant treatment at two different sites with osseous defects were planned for this split-mouth study. After inserting the dental implants, peri-implant defects were treated according to the GBR technique using a VN membrane with prolonged resorption time in the randomised test site and a BG membrane in the control site. After a healing time of 6 months, mucoperiosteal flaps were elevated for the evaluation of the primary (vertical bone fill [ΔDL] and quality of newly formed tissue [QT]) and secondary outcome variables (infrabony defect height [DH], defect width [DW], defect depth [DD] and augmentation depth [AD]) and the sampling of biopsies apical to the implant shoulder. RESULTS: A total of 16 patients fulfilled the initial non-surgical inclusion and exclusion criteria. However, the study was discontinued early after 9 surgically treated patients because unacceptable safety issues arose and severe infection related to the VN membranes. The VN membrane revealed statistically significantly more soft tissue dehiscence than the BG membrane (56% and 11%, respectively, P = 0.0455). In 3 of these 9 patients the VN membrane had to be removed due to infection early after the first follow-up visit. For the statistical analyses these sites were designated as the value of the baseline. The mean ΔDL values were 1.8 ± 1.6 mm at the VN site and 4.7 ± 3.3 mm at the BG site. The ΔDD values were 0.6 ± 1.0 mm and 1.1 ± 1.2 mm, respectively, and reached statistical significance (P = 0.0208, CI 95% = -2.9 [-5.2;-0.6]). The corresponding linear defect fill (DF) values were 44% and 78%, respectively. The clinical assessment of QT showed comparable median values at sites treated with VN (3, interquartile range: 0; 3.5) and BG (3, interquartile range: 3; 4) without statistical significance. The histomorphometric analysis showed an average area density of 24.4% (SD 10.3, range 8-35%) newly formed bone at the test sites and of 35.0% (SD 20.6, range 8-60%) at the control sites. The histological data showed only some trends and did not reach statistical significance. CONCLUSION: In the present study, the VN membranes with prolonged resorption time demonstrated significantly more adverse events and insufficient bone regeneration compared to the native BG membranes and no advantages in favour of the VN membranes were detectable.