Biomedical subjects

Periklis Proussaefs

Publications and source records attributed to Periklis Proussaefs.

At least 19 recordsLinked to original sources

PubMed2006

Use of titanium mesh for staged localized alveolar ridge augmentation: clinical and histologic-histomorphometric evaluation.

The use of titanium mesh for localized alveolar ridge augmentation was evaluated by clinical, radiographic, laboratory, and histologic-histomorphometric evaluation. Seventeen patients participated in this study. All patients required localized alveolar ridge augmentation before placement of dental implants. An equal mixture of autogenous bone graft and inorganic bovine mineral (Bio-Oss) was used as a bone graft material. Autogenous bone graft was harvested intraorally. Titanium mesh was submerged for 8.47 months (SD 2.83). Impressions were taken intraorally before bone grafting, 6 months after bone grafting, and 6 months after implant placement. Impressions were used to measure the volume of alveolar ridge augmentation and provide linear laboratory measurements regarding the results of bone augmentation. Bone quality (type II-IV) was recorded during implant surgery. Standardized linear tomographs were taken before bone grafting and before implant placement. A biopsy was harvested with a trephine bur from the grafted area during implant surgery for histologic-histomorphometric evaluation. In all cases the grafted area had adequate bone volume and consistency for placement of dental implants. Early mesh exposure (2 weeks) was observed in 2 patients, and late exposure (>3 months) was observed in 4 patients. Volumetric laboratory measurements indicated 0.86 cc (SD 0.69) alveolar augmentation 1 month after bone grafting, 0.73 cc (SD 0.60) 6 months after bone grafting, and 0.71 cc (SD 0.57) 6 months after implant placement. This indicated 15.11% resorption 6 months after bone grafting, and no further resorption occurred after implant placement. Linear laboratory measurements indicated vertical augmentation of 2.94 mm (SD 0.86) 1 month after bone grafting, 2.59 mm (SD 0.91) 6 months after bone grafting, and 2.65 mm (SD 1.14) 6 months after implant placement. The corresponding measurements for labial-buccal augmentation were 4.47 mm (SD 1.55), 3.88 mm (SD 1.43), and 3.82 mm (SD 1.47). Radiographic evaluation indicated 2.56 mm (SD 1.32) vertical augmentation and 3.75 mm (SD 1.33) labial-buccal augmentation. Histomorphometric evaluation indicated 36.47% (SD 10.05) new bone formation, 49.18% (SD 6.92) connective tissue, and 14.35% (SD 5.85) residual Bio-Oss particles; 44.65% (SD 22.58) of the Bio-Oss surface was in tight contact with newly formed bone. The use of titanium mesh for localized alveolar ridge augmentation with a mixture of autogenous intraorally harvested bone graft and Bio-Oss offered adequate bone volume for placement of dental implants. Intraorally harvested autogenous bone graft mixed with Bio-Oss under a titanium mesh offered 36.47% new bone formation, and 15.11% resorption occurred 6 months after bone grafting.

Adolescent↗

PubMed2006

Clinical and histologic evaluation of the use of mandibular tori as donor site for mandibular block autografts: report of three cases.

The present paper reports on three patients who underwent localized alveolar ridge augmentation using block autografts harvested from the mandibular tori. Autogenous particulate bone graft was placed at the periphery of the block. Resorbable collagen membrane was placed above the graft material. Implant placement surgery followed at 6 to 16 months after bone grafting. During implant surgery, a biopsy was taken from the block autograft. Clinical evaluation revealed incorporation of the graft material at the recipient site. No donor site complication was noted. Histologic evaluation suggested that the block autograft was vital and in an active remodeling phase at the time of implant placement. Impressions were made intraorally before and 6 months after bone grafting. Laboratory measurements revealed 13% resorption at 6 months after bone grafting while 0.53 mL of ridge augmentation was achieved 6 months after bone grafting. Linear tomographs indicated 4.33 mm of lateral alveolar ridge augmentation. This report suggests that block autografts harvested from the mandibular tori may have the potential to maintain their vitality after bone grafting, while they may demonstrate resorption rates similar to those of autografts harvested from other intraoral donor sites.

Absorbable Implants↗

PubMed2005

Inferior alveolar nerve transposing in a situation with minimal bone height: a clinical report.

Previous studies have indicated that at least 5 mm of bone is needed above the canal when performing transposing of the inferior alveolar nerve (TIAN). In this clinical report, TIAN was performed in a situation where minimal (< 2 mm) bone height was present above the canal of the IAN. Preoperative examination with computerized tomography scan revealed 2 mm of bone above the canal at the area of teeth #18 to #20, #30, and #31. The TIAN was performed by opening a lateral access window along the lateral side of the mandible. Five threaded hydroxyapatite-coated root form implants were placed at the area of teeth #18 to #20, #30, and #31. Autogenous bone from the lateral access window that was removed en block was particulated and placed around the implants. A resorbable collagen membrane was placed around the graft material. Implants were restored with cement-retained implant-supported metal-ceramic crowns. Three-year post-loading examination revealed minimal bone loss (< 1 mm).

Alveolar Ridge Augmentation↗

PubMed2005

The use of intraorally harvested autogenous block grafts for vertical alveolar ridge augmentation: a human study.

This study presents a clinical, radiographic, laboratory, and histologic/histomorphometric analysis of the use of mandibular block autografts for vertical alveolar ridge augmentation. Twelve patients were included in the study. The autogenous block autografts were fixated at the recipient sites with screws, and a mixture of autogenous bone marrow and inorganic bovine mineral (Bio-Oss) was used at the periphery. At re-entry surgery, all the grafts appeared well incorporated at the recipient sites. Radiographic measurements revealed an average of 5.75 +/- 1.29 mm vertical ridge augmentation at 1 month after surgery and 4.75 +/- 1.29 mm at 4 to 6 months after surgery. This indicated 17.4% resorption. Laboratory volumetric measurements revealed an average of 0.84 +/- 0.34 mL of alveolar ridge augmentation 1 month after surgery and 0.71 +/- 0.28 mL at 6 months postoperatively. The resorption rate according to the laboratory volumetric measurements was 15.5%. Linear laboratory measurements revealed 5.92 +/- 1.38 mm of vertical ridge augmentation 1 month postoperatively and 4.08 +/- 1.01 mm at 4 to 6 months after surgery. Histologic evaluation of the block autografts indicated signs of active remodeling activity in 10 of the 12 specimens. In one case the block graft became exposed and infected, and in another case the block autograft became dislodged during implant placement surgery. Histomorphometric analysis of the peripheral particulate bone indicated bone present at 33.99% +/- 8.82% of the graft surface, while 42.43% +/- 11.06% of the area was occupied by fibrous tissue and 23.89% +/- 9.12% was made up of residual Bio-Oss particles. Residual Bio-Oss particles were in tight contact with newly formed bone along 58.57% +/- 15.22% of their perimeter.

Aged↗

PubMed2004

The effectiveness of auxiliary features on a tooth preparation with inadequate resistance form.

STATEMENT OF PROBLEM: No study has evaluated the efficacy of auxiliary tooth preparation elements for crowns with originally reduced resistance form. PURPOSE: This study evaluated the effects of different auxiliary preparation features on the resistance form of crowns with reduced axial wall and total occlusal convergence. MATERIAL AND METHODS: An Ivorine tooth was prepared on a milling machine with 20-degree total occlusal convergence (TOC), 2.5 mm of occlusocervical dimension, and a shoulder finish line. This design lacked geometric resistance form. The crown preparation was subsequently modified to include mesiodistal grooves, mesiodistal boxes, buccolingual grooves, occlusal inclined planes, an occlusal isthmus, and reduced TOC in the axial wall from 20 to 8 degrees TOC in the cervical 1.5 mm of the axial wall. The grooves and boxes were placed into the tooth with the same 20-degree TOC as the initial axial walls. Ten standardized metal dies were used for each preparation design. Standardized complete metal crowns were fabricated for all specimens. The metal crowns were cemented on metal dies with resin-modified glass ionomer cement. A strain gauge was placed at the mid-lingual cervical area of each crown preparation margin. The resistance of each specimen was evaluated when force was applied at a 45-degree angulation to the long axis of the die in a lingual to buccal direction. The peak loads during crown dislodgment, as well as the tensile stress at the mid-lingual cervical area, were measured using a universal testing machine (Kgs) for each specimen. The control group consisted of 10 dies, with the original crown preparation having no geometric resistance form and no auxiliary preparation features. Strain gauges provided the force (Kgs) that resulted in electric currency disrupt at the crown/die interface, thus providing data regarding the force required for slight crown micromovement (2 microm). Data between control and experimental groups were compared using the Mann-Whitney U test (alpha=.05). RESULTS: Proximal grooves, proximal boxes, buccolingual grooves, occlusal inclined planes, and occlusal isthmuses were not effective at increasing a crown's resistance to dislodgement when the tooth preparation lacked resistance. The only crown modification that offered enhanced resistance form when compared with the control group was the reduced TOC in the cervical half of the axial wall. CONCLUSION: Within the limitations of this in vitro study the crown preparation modification that significantly enhanced the resistance form of a compromised tooth preparation was reducing the TOC at the cervical aspect of the axial wall. Placing auxiliary retentive features such as grooves and boxes into a compromised tooth preparation (2.5 mm occlusocervical dimension and 20-degree TOC) was not effective when these retentive features possessed the same 20-degree TOC as the prepared axial walls.

Cementation↗

PubMed2004

Immediate loading of hydroxyapatite-coated implants in the maxillary premolar area: three-year results of a pilot study.

STATEMENT OF THE PROBLEM: Although immediate loading of implants in the edentulous mandible has been described in the literature, there is limited information regarding immediate loading of single implants. PURPOSE: This prospective clinical study evaluated the clinical parameters of immediately loaded single-threaded hydroxyapatite-coated (HA) root form implants. MATERIAL AND METHODS: Ten human subjects were included in this report. In all situations, a screw-retained provisional acrylic resin crown was placed in the maxillary premolar area immediately after implant surgery. Definitive screw-retained metal-ceramic prostheses were placed 6 months after surgery. Standardized periapical radiographs were made before implant surgery, immediately after surgery, and 1, 3, 6, 12, and 36 months after implant surgery. Mobility (measured with the Perio-Test), distance from implant platform to the gingival crevice, distance from the implant platform to the depth of the sulcus, peri-implant probing depth, and bleeding on probing index were recorded at 3, 6, 12, and 36 months after implant placement. For clinical measurements, a 5-mm healing abutment was placed. RESULTS: All implants appeared clinically osseointegrated. Standardized radiographs demonstrated mean marginal bone loss of 0.6, 0.7, 0.8, 0.9, and 1.0 mm at 1, 3, 6, 12, and 36 months after implant surgery, respectively. Mean implant mobility was -3.3 at the day of surgery and -3.8, -3.4, -3.6, and -4.2 at 3, 6, 12, and 36 months, respectively. The distance from implant platform to the gingival crevice was 2.8, 2.4, 2.4, and 3.1 mm at 3, 6, 12, and 36 months, respectively. The distance from the implant platform to the depth of the sulcus was 0.8, 0.9, 0.9, and 1.1 mm at 3, 6, 12, and 36 months, respectively. The peri-implant probing depth was 3.6, 3.3, 3.2, and 4.3 mm at 3, 6, 12, and 36 months, respectively. The bleeding on probing index was 0.4, 0.4, 0.4, and 0.1 at 3, 6, 12, and 36 months, respectively. CONCLUSION: The results of this prospective pilot study provide initial evidence that single root form implants may be immediately loaded when placed at the maxillary premolar area.

Adult↗

PubMed2004

Histologic evaluation of a 12-year-old threaded hydroxyapatite-coated implant placed in conjunction with subantral augmentation procedure: a clinical report.

This clinical report presents a histologic evaluation of a threaded hydroxyapatite-coated root-form implant retrieved from the posterior maxillary area of a patient after being in function for 12 years. The implant had been placed in conjunction with subantral augmentation. Histologically, the portion of the implant that was examined under light microscopy appeared to be integrated with the surrounding bone; 74.3% of the surface of the implant had close bone apposition at the interface. The residual graft particles were present and in close proximity to the implant surface. These observations suggest that subantral augmentation procedure performed simultaneously with the placement of a hydroxyapatite-coated implant by using hydroxyapatite as a graft material may result in osseointegration between the implant and the surrounding bone that can be maintained under long-term function.

Aged↗

PubMed2004

Crowns cemented on crown preparations lacking geometric resistance form. Part II: effect of cement.

PURPOSE: This study evaluated the effect of different cements on resistance to dislodgment of crowns cemented on preparations lacking geometric resistance form. MATERIALS AND METHODS: A preparation that offered no geometric resistance form, with 20 degrees total occlusal convergence (TOC), 0.9 mm wide shoulder finish line, and a 2.5 mm axial wall height was created on an ivorine tooth using a milling machine. Ten metal test specimen die replicas and 10 standardized metal crowns with recipient sites for the application of external forces through a universal testing machine were fabricated. The crowns were cemented on the dies under 5 and 10 kg external loads, the marginal openings measured, loaded to dislodgment, and cleaned of cement. The process was repeated using zinc oxide and eugenol (ZOE), zinc phosphate (ZPh), resin modified glass ionomer (RMGI), and composite resin (CR) cements. RESULTS: Marginal openings under 5 kg cementation loads were 74.63 (+/-15.04) for ZOE, 75.98 (+/-18.20) microm for ZPh, 98.58 (+/-22.62) microm for RMGI, and 105.82 (+/-20.07) microm for CR cements respectively; under 10 kg cementation loads they were 57.62 (+/-15.86) microm, 59.55 (+/-15.41) microm, 95.00 (+/-19.52) microm, 101.30 (+/-12.52) microm respectively. Oblique dislodgment forces, measured with a Universal testing machine, were 40.18 (+/- 6.76) N for ZOE, 215.65 (+/-45.79) N for ZPh, 165.43 (+/-19.53) N for RMGI, and 181.54 (+/-30.75) N for CR respectively when crowns were cemented under 5 kg loads. The corresponding values for 10 kg loads were 38.62 (+/-4.19), 274.86 (+/-54.22), 139.70 (+/-21.71), and 160.40 (+/-21.21) respectively. Only zinc phosphate cement produced statistically enhanced resistance when crowns were cemented under 10 kg force (p value = 0.035). CONCLUSIONS: Under the conditions of the present study only crowns cemented with zinc phosphate displayed increased resistance to dislodgment on preparations lacking resistance form.

Cementation↗

PubMed2004

Clinical and laboratory steps for the fabrication of a fixed, cement-retained, implant-supported, complete-arch maxillary prosthesis.

The fabrication of a complete-arch maxillary prosthesis has been associated with several prosthetic complications and difficulties. Although it has been reported that phonetics, esthetics, and proper lip support are difficult to achieve, there is a scarcity of literature on the clinical and laboratory procedures necessary to minimize these complications. The current article provides clinical and laboratory steps that may enable the clinician to achieve more predictable restorative results when fabricating a cement-retained, implant-supported, complete-arch maxillary prosthesis.

Cementation↗

PubMed2003

The use of resorbable collagen membrane in conjunction with autogenous bone graft and inorganic bovine mineral for buccal/labial alveolar ridge augmentation: a pilot study.

STATEMENT OF PROBLEM: No study provides human histologic evidence regarding the use of resorbable collagen membrane for a 2-stage localized alveolar augmentation procedure. PURPOSE: The purpose of this pilot study was to evaluate the potential of use of a resorbable collagen membrane in conjunction with an autogenous bone graft and inorganic bovine mineral (IBM) for labial/buccal alveolar ridge augmentation prior to placing dental implants. Material and methods Seven consecutively treated human patients participated in the study. All patients received labial/buccal alveolar ridge augmentation. An autogenous block graft was secured at the recipient site with fixation screws and a mixture of autogenous particulate with IBM was placed at the periphery. Resorbable collagen membrane was used as a barrier. Radiographic and laboratory measurements were made to quantify ridge augmentation and resorption rate. Preoperative and postoperative stone casts were used to quantify alveolar ridge augmentation. Volumetric evaluation was measured in mL whereas linear laboratory evaluation was measured in millimeters. Measurements were made 1 and 6 months after bone grafting. Histologic and histomorphometric analysis from the grafted area evaluated new bone formation, and osteoconductivity of IBM. RESULTS: For all patients Type II to III bone quality was achieved at the augmented sites. The implant survival rate was 100% at second-stage surgery. No complication was observed at the recipient sites. Radiographic evaluation revealed 4.65 mm labial/lingual augmentation, whereas laboratory analysis revealed 4.57 mm. Volumetric laboratory analysis demonstrated 1.00 (+/- 0.29) mL alveolar ridge augmentation 6 months after bone grafting and 13.79% resorption between months 1 and 6. Histomorphometric analysis revealed that on average, the area occupied by bone was 34.28% (range 24 to 50; +/-9.05),] soft tissue 46.00% (+/-9.20%; range 30% to 55%), and IBM particles 19.71% (+/-11.74%, range 3% to 42%). The proportion of the surface of the IBM particles in contact with bone was 47.14% (range 15% to 64%; SD 17.21%). CONCLUSIONS: Resorbable collagen membranes may be used as barriers for labial/buccal alveolar ridge augmentation procedures.

Absorbable Implants↗

PubMed2003

Histologic evaluation of an immediately loaded titanium provisional implant retrieved after functioning for 18 months: a clinical report.

Histologic evaluation of a single immediately loaded titanium provisional implant that was in function for 18 months revealed 81.3% bone-to-implant contact of the surface evaluated, whereas 9.6% of the implant surface evaluated was opposed by marrow and 9.1% by connective tissue. The bone appeared to be in active remodeling stage and in close contact with the implant surface.

Bone Marrow↗

PubMed2003

The "Loma Linda stent": a screw-retained resin stent.

This article describes a technique in which an acellular dermal allograft is used in combination with a photopolymerized acrylic resin stent to increase the zone of keratinized tissue around osseointegrated dental implants. During the second-stage surgery, a split thickness labial flap is reflected and apically repositioned by being sutured onto the periosteum and connective tissue. The acellular dermal allograft is then sutured onto the recipient site. The acrylic resin is trimmed and secured with temporary abutments to the implants, fitting passively over the graft and then photopolymerized intraorally. The stent is left for 1 week to secure the graft in place. This technique offers an alternative mucogingival procedure for increasing the zone of keratinized tissue around osseointegrated dental implants.

Acrylic Resins↗

PubMed2003

Effects of sealing the perforated sinus membrane with a resorbable collagen membrane: a pilot study in humans.

The effects of repairing the perforated sinus membrane with collagen membrane are unknown. The purpose of this pilot study was to clinically, histologically, and histomorphometrically evaluate the results of repairing the perforated sinus membrane with resorbable collagen membrane. A split-mouth design was followed in the current study. Five subjects requiring bilateral sinus grafting were included in the study, where one site was accidentally perforated during sinus augmentation procedures and the other site was not perforated. The perforated sites were repaired with a resorbable collagen membrane. Dental implants were placed at a second stage and biopsies were harvested from both sinuses. New bone formation was measured for all sites. Implant survival was recorded at second-stage surgery. Nonperforated sites demonstrated significantly more bone formation (34.40%) than perforated sites (12.80%) (P = .016). Implant survival at second-stage surgery was significantly inferior in perforated sites (54.5%) when compared with nonperforated sites (100%) (P = .0146). The study demonstrated that perforation and repair of the Schneiderian membrane can compromise new bone formation and implant survival rate.

Absorbable Implants↗

PubMed2003

The use of titanium mesh in conjunction with autogenous bone graft and inorganic bovine bone mineral (bio-oss) for localized alveolar ridge augmentation: a human study.

This study evaluated the effects of using a titanium mesh for localized alveolar ridge augmentation. Seven consecutively treated human subjects participated in the study. Clinical, radiographic, laboratory, and histologic/histomorphometric analysis revealed the efficacy of using the titanium mesh in conjunction with intraorally harvested autogenous bone graft and inorganic bovine bone mineral (Bio-Oss). Radiographic measurements detected that a 2.86-mm vertical and 3.71-mm buccolabial ridge augmentation was achieved, while histomorphometry demonstrated that 36.4% of the grafted area consisted of bone. Laboratory measurements revealed 15.08% resorption of the graft for the first 6 months, which appeared to consolidate after placement of the implants. Exposure of the mesh did not appear to compromise the result.

Adult↗

PubMed2003

The "Loma Linda pouch": a technique for repairing the perforated sinus membrane.

A technique, the "Loma Linda pouch," is introduced for repairing the perforated maxillary sinus membrane during sinus grafting procedures. A collagen membrane is placed against the perforated site and subsequently covers the internal surface of the maxillary sinus. The collagen membrane is then folded along the lateral access window to form a pouch that surrounds and isolates the graft material.

Collagen↗

PubMed2002

The use of healing abutments for the fabrication of cement-retained, implant-supported provisional prostheses.

This article describes the intraoral preparation of healing abutments for use as prefabricated abutments for a cement-retained, implant-supported prosthesis. After the healing abutments are prepared, an impression is made with irreversible hydrocolloid, and the provisional restoration is fabricated indirectly. This technique is an easy and economical alternative for the fabrication of provisional fixed partial dentures or crowns but may be contraindicated for severely misaligned implants.

Acrylic Resins↗

PubMed2002

Histologic evaluation of a threaded hydroxyapatite-coated root-form implant located at a dehisced maxillary site and retrieved from a human subject: a clinical report.

This clinical report describes the microscopic analysis of a threaded hydroxyapatite-coated root-form implant retrieved from an 89-year-old subject after 10 months of service. The implant was never loaded and was removed because it was nonrestorable. Clinically, the buccal area of the implant was covered by soft tissue, whereas the palatal side was covered by bone. Light microscopic evaluation revealed tight contact between hydroxyapatite and bone with no sign of coating dissolution. Osteocytes were present, and Haversian canals were in close proximity to the implant surface. The buccal side of the implant demonstrated mild to moderate inflammatory infiltrate and signs of hydroxyapatite coating dissolution. These observations suggest that hydroxyapatite coatings can resist degradation in contact with bone but may be more prone to dissolution in contact with soft tissue.

Aged↗

PubMed2002

A maxillary screw-retained, implant-supported diagnostic wax pattern.

This article describes the fabrication of a screw-retained, implant-supported wax pattern that enables the restorative dentist to predict the outcome of the final prosthesis. The wax pattern also affords the patient an opportunity to evaluate and approve the design of the planned prosthesis, thereby enhancing communication between the dentist and patient.

Dental Impression Materials↗