Increase In Ridge Width Research Articles

Contour Changes Following Implant Placement and Concomitant Soft Tissue Augmentation Applying a Volume-Stable Collagen Matrix.

The objective of this study was to assess volumetric and linear changes of buccal mucosal thickness at implant sites following soft tissue augmentation with a volume-stable collagen matrix (VCMX). Soft tissue augmentation using a VCMX was performed in 12 patients at the time of implant placement. Hydrocolloid impressions were taken prior to surgery and at 1 and 6 months postsurgery. Stone cast models were scanned, and stereolithography (STL) files from the three time points were uploaded to an image-analysis software. At all time points, linear and volumetric measurements of the contour changes up to 3 mm apical to the mucosal margin were performed and were analyzed statistically. At 1 mm apical to the mucosal margin, the change in soft tissue thickness between presurgery (T1) and 1 month (T2) amounted to 0.21 ± 1.22 mm, and the change between T1 and 6 months (T3) was 0.08 ± 1.47 mm. At 3 mm apical to the mucosal margin, the change in soft tissue thickness was 1.92 ± 1.70 mm between T1 and T2 and 0.31 ± 1.26 mm between T1 and T3. Contour (volumetric) changes revealed an increase of 0.58 ± 0.73 mm between T1 and T2 and an overall gain of 0.55 ± 0.73 mm between T1 and T3. Soft tissue augmentation with VCMX increased the ridge profile. The increase in ridge width was greater at 3 mm below the ridge crest than at 1 mm below the ridge crest. Remodeling processes during healing showed a decrease in the ridge contour between 1 and 6 months.

HORIZONTAL ALVEOLAR RIDGE AUGMENTATION USING XENOGENIC BONE GRAFT: A COMPARISON BETWEEN THE FLAP AND SUBPERIOSTEAL TUNNELING TECHNIQUES

Abstract Background: The aim of this study was to evaluate the prognosis of minimal invasive horizontal alveolar ridge augmentation using small incision and subperiosteal tunneling technique. Methods: This study was conducted on 10 partially edentulous patients with horizontal alveolar bone deficiency in 12 areas that need horizontal alveolar ridge augmentation for future implant placement. Cone beam computer tomography was done for sites that need implant placement preoperatively. Xenogeneic bone was used for grafting deficient horizontal alveolar ridge sites using the flap technique in 6 areas and using the subperiosteal tunneling technique in another 6 areas for future implant placement. Cone beam computer tomography was done for grafted sites immediately postoperative and 6 months postoperative. Results: This study was conducted on 10 patients and included 12 implant sites. No complications related to bone grafting were found and there was an adequate clinical prognosis. Regarding the difference from pre-operatively to 6 months post-operatively, a slightly higher increase in ridge width was recorded in subperiosteal tunnel group (1.48±0.99) in comparison to flap group (0.91±0.94), with no statistically significant difference (p=0.086). Conclusions: The bone graft material retained within a pouch formed using small incision and subperiosteal tunneling technique resulted in additional increase within the width of the alveolar ridge than the flap technique. Keywords: alveolar ridge augmentation, Dental implants, xenogeneic bone graft and subperiosteal tunneling technique.

Investigating the interplay of lateral and height dimensions influencing neuronal processes on nanogrooves

In this work, nanogroove dimensions as a design input parameter for neuronal differentiation and neurite outgrowth in brain-on-a-chip (BOC) applications are investigated. Soft lithography in polydimethylsiloxane (PDMS) is used extensively in organ-on-a-chip applications to create environments for in vitro models. As such, here it is used to fabricate cell culture substrates with nanogrooved patterns. Using a newly developed analysis method, the effect of the nanogrooved, biomimetic PDMS substrates is compared with lateral and height variations within the nanometer range as measured by means of atomic force microscopy (AFM). PDMS culture substrates were replicated from a cyclic olefin copolymer template, which was fabricated either directly by thermal nanoimprinting from a jet and flash imprint lithography (J-FIL) resist pattern (process I) on a polished silicon wafer or via an intermediate reactive ion etched all-silicon mold (process II) that was fabricated by using the J-FIL resist pattern as in process I as a mask. To study the interplay between the lateral and height dimensions of nanogrooves on the differentiation process of SH-SY5Y cells, which are a well-established model for neuronal cells that form networks in culture, the authors first characterized the feature sizes of the PDMS substrates received from both processes by AFM. On average, nanogrooved patterns from process I had a 1.8 ± 1.1% decrease in pattern period, a 15.5 ± 12.2% increase in ridge width compared to the designed dimensions, and a height of 95.3 ± 10.6 nm. Nanogrooved patterns for process II had a 1.7 ± 1.7% decrease in pattern period, a 43.1 ± 33.2% increase in ridge width, and a height of 118.8 ± 13.6 nm. Subsequently, they demonstrated that neurite outgrowth alignment was particularly strong if the pattern period was 600 nm or 1000 nm with the additional constraint for these patterns that the ridge width is <0.4 times the pattern period. Increasing pattern height increased the fraction of differentiated cells within the cell culture and increased neurite length, but had no direct impact on outgrowth alignment. This study forms the basis for optimization in the bottom-up engineering of neuronal network architecture, for which specific patterns can be selected to assist in neuronal cell differentiation and direct neurite growth and alignment. Such organized neuronal networks can aid in the design of in vitro assay systems for BOC applications by improving biological response readouts and providing a better understanding of the relationship between form and function of a neuronal network.

Lateral alveolar ridge augmentation procedure using subperiosteal tunneling technique: a pilot study

BackgroundIn this research article, we evaluate the use of sub-periosteal tunneling (tunnel technique) combined with alloplastic in situ hardening biphasic calcium phosphate (BCP, a compound of β-tricalcium phosphate and hydroxyapatite) bone graft for lateral augmentation of a deficient alveolar ridge.MethodsA total of 9 patients with deficient mandibular alveolar ridges were included in the present pilot study. Ten lateral ridge augmentation were carried out using the sub-periosteal tunneling technique, including a bilateral procedure in one patient. The increase in ridge width was assessed using CBCT evaluation of the ridge preoperatively and at 4 months postoperatively. Histological assessment of the quality of bone formation was also carried out with bone cores obtained at the implant placement re-entry in one patient.ResultsThe mean bucco-lingual ridge width increased in average from 4.17 ± 0.99 mm to 8.56 ± 1.93 mm after lateral bone augmentation with easy-graft CRYSTAL using the tunneling technique. The gain in ridge width was statistically highly significant (p = 0.0019). Histomorphometric assessment of two bone cores obtained at the time of implant placement from one patient revealed 27.6% new bone and an overall mineralized fraction of 72.3% in the grafted area 4 months after the bone grafting was carried out.ConclusionsWithin the limits of this pilot study, it can be concluded that sub-periosteal tunneling technique using in situ hardening biphasic calcium phosphate is a valuable option for lateral ridge augmentation to allow implant placement in deficient alveolar ridges. Further prospective randomized clinical trials will be necessary to assess its performance in comparison to conventional ridge augmentation procedures.

Clinical and Histomorphometric Assessment of Lateral Alveolar Ridge Augmentation Using a Corticocancellous Freeze-Dried Allograft Bone Block.

Horizontal ridge augmentation with allografts has attracted notable attention because of its proper success rate and the lack of disadvantages of autografts. Corticocancellous block allografts have not been adequately studied in humans. Therefore, this study clinically and histomorphometrically evaluated the increase in ridge width after horizontal ridge augmentation using corticocancellous block allografts as well as implant success after 12 to 18 months after implantation. In 10 patients receiving implants (3 women, 7 men; mean age = 45 years), defective maxillary alveolar ridges were horizontally augmented using freeze-dried bone allograft blocks. Ridge widths were measured before augmentation, immediately after augmentation, and ∼6 months later in the reentry surgery for implantation. This was done at points 2 mm (A) and 5 mm (B) apically to the crest. Biopsy cores were acquired from the implantation site. Implant success was assessed 15.1 ± 2.7 months after implantation (range = 12-18 months). Data were analyzed using Friedman and Dunn tests (α = 0.05). At point A, ridge widths were 2.77 ± 0.37, 8.02 ± 0.87, and 6.40 ± 0.66 mm, respectively, before surgery, immediately after surgery, and before implantation. At point B, ridge widths were 3.40 ± 0.39, 9.35 ± 1.16, and 7.40 ± 1.10 mm, respectively, before surgery, immediately after surgery, and before implantation. The Friedman test showed significant increases in ridge widths, both at point A and point B (both P = .0000). Postaugmentation resorption was about 1.5-2 mm and was statistically significant at points A and B (P < .05, Dunn). The percentage of newly formed bone, residual graft material, and soft tissue were 33.0% ± 11.35% (95% confidence interval [CI] = 24.88%-41.12%), 37.50% ± 19.04% (95% CI = 23.88%-51.12%), and 29.5%, respectively. The inflammation was limited to grades 1 or zero. Twelve to 18 months after implantation, no implants caused pain or showed exudates or pockets. Radiographic bone loss was 2.0 ± 0.7 mm (range = 1-3). It can be concluded that lateral ridge augmentation with corticocancellous allograft blocks might be successful both clinically and histologically. Implants might have a proper clinical success after a minimum of 12 months.

Lateral Ridge Augmentation with Autogenous Bone Harvested Using Trephine Drills: A Noninvasive Technique.

Purpose:The aim of this pilot study was to evaluate the success rate of a chairside ridge augmentation procedure using bone autografts harvested with trephine drills and placed without the use of screws.Methods:Thirty patients were recruited for the study. After the surgical site was anesthetized and a crestal incision was made, an envelope flap was retracted using blunt dissection limited to the graft site, and the periosteum was raised intact and undamaged from the bone. The flap was extended laterally to obtain sufficient space for the bone graft. At the donor site, bone was obtained from the external oblique ridge area. A #5 or #6 trephine drill was used to harvest one or two pieces of bone. The bone blocks were placed inside the envelope flap at the recipient site, which was then sutured and covered with periodontal dressing. Antibiotics, analgesics, and mouthwash were prescribed. Measurements of ridge width were performed using CBCT before and 3 months after surgery. The pre- and post operative results were compared using paired t test.Results:Pre- and post-operative mean ridge widths were 2.23 ± 0.79 and 5.16 ± 0.68 mm, respectively. The mean increase in width was 2.92 ± 0.89 mm(P < 0.001).Conclusion:This non-invasive and simple technique provided an acceptable increase in ridge width. As the sample was small, we recommend further clinical investigation with larger samples to confirm that this technique may be used successfully as an alternative to current invasive augmentation methods.

Delayed expansion of the atrophic mandible by ultrasonic surgery: a clinical and histologic case series.

Ridge expansion is used to widen narrow ridges with adequate height for implant placement. This human case series presents the clinical and histologic results of delayed expansion of mandibles by ultrasonic surgery. Patients with residual alveolar ridge width between 2.3 and 4.1 mm in the coronal area of the posterior mandible were included in the study. First, four linear corticotomies were carried out by ultrasonic surgical device. Four weeks later, adequate bone expansion with a combination of scalpels, thin chisels, and threaded osteotomes that did not compromise cortical vascularization was performed, and two implants per ridge were inserted. Any gaps were filled with corticospongious porcine biomaterial. Three months after implant placement, healing caps were inserted, and bone cores were harvested from the regenerated areas for histologic analysis. Crestal width was recorded at each surgery. The postoperative course was uneventful in all 32 patients (64 implants) who took part in the study, and the implant success rate was 96.88% at 3 months. The mean increase in ridge width was 5.17 ± 0.86 mm. The histologic specimens showed a mixture of new bone and particles of biomaterial, as well as newly formed bone. Histomorphometry demonstrated that 64% ± 3.1% of the specimen was composed of newly formed bone, 8% ± 0.8% was made up of marrow spaces, and 27% ± 2.6% comprised the residual grafted biomaterial. This study showed that mandibular ridge expansion using a delayed split-crest technique by means of ultrasonic surgery and association with biomaterial led to good horizontal bone gain, with no fractures of the buccal plate, and a high implant success rate. The histologic specimens showed newly formed bone and good integration of the biomaterial.

Clinical Evaluation of Freeze-Dried Cancellous Block Allografts for Ridge Augmentation and Implant Placement in the Maxilla

A number of grafting materials have been used in vertical and horizontal ridge augmentation to enable implant placement in optimal positions. Autogenous block grafts from intraoral or extraoral sites have been used with positive results. Allograft blocks with cortical bone are also used for ridge augmentation. In this case series, cancellous allograft blocks were used for horizontal augmentation of the maxilla. The observed increase in ridge width allowed subsequent implant placement after a 5-month healing period. Four months after placement, the implants were uncovered and restored. The results suggest that cancellous block allografts may be a viable alternative to autogenous block grafts or cortical allograft blocks in treatment of deficient maxillary alveolar ridges to allow subsequent implant placement in optimal position in the maxilla.

Clinical Evaluation of a Cancellous Block Allograft for Ridge Augmentation and Implant Placement: A Case Report

A number of grafting materials have been used in vertical and horizontal ridge augmentation to enable implant placement in optimal positions. Autogenous block grafts from intraoral or extraoral sites have been used with positive results. Allograft blocks with cortical bone are also used for ridge augmentation. In this case report, a cancellous allograft block was used for horizontal augmentation of the maxilla. The observed increase in ridge width allowed subsequent implant placement after a 5 month healing period. After 4 months the implant was uncovered and restored as a unit in a 4-unit fixed splinted implant reconstruction. The result suggests that cancellous block allografts may be a promising alternative to autogenous block grafts or cortical allograft blocks in treatment of deficient maxillary alveolar ridges to allow subsequent implant placement in optimal position.

Alveolar ridge augmentation using titanium micromesh: An experimental study in dogs

Purpose: Augmentation of the alveolar ridge before implant placement is frequently performed. The purpose of this study was to compare the amount and quality of bone formation under Micro Titanium Augmentation Mesh (M-TAM) when used alone for guided tissue regeneration or in combination with a porous hydroxyapatite (HA) bone graft substitute. Materials and Methods: Nine adult female dogs underwent extraction of premolars and molars and had a knife-edge ridge created. Three months later, the ridges were augmented with either M-TAM alone or M-TAM with a nonresorbable porous HA (Interpore 200; Interpore Cross International, Irvine, CA). Six months after augmentation, the dogs were killed, and the mandibles were harvested and imaged using 3-dimensional computed axial tomography. Statistical analysis was performed from the data obtained from the scans. The mandibles were then fixed, sectioned, and examined by light microscopy. Results: Dehiscence occurred in 22 of 32 experimental sites. Seven of these 22 dehisced sites showed increased ridge width. Ridge width increased in both the HA and non-HA groups. The HA group showed a greater increase in ridge width. Conclusion: A high rate of dehiscence was observed in this animal study using M-TAM for guided tissue regeneration. In animals that did not dehisce, increased width was greater when nonresorbable porous HA was used as a bone graft substitute. © 2003 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 61:347-353, 2003

Perceived roughness of a grating: correlation with responses of mechanoreceptive afferents innervating the monkey's fingerpad

Human subjects scaled gratings of alternating grooves and ridges for perceived roughness. Roughness increased with an increase in groove width and decreased with an increase in ridge width, but the effect of groove width was much greater than the effect of ridge width. In corresponding neurophysiological experiments, the gratings were moved sinusoidally across the receptive fields of single mechano-receptive afferents innervating the fingerpads of anesthetized monkeys. The measure of response used was the mean cyclic discharge rate (averaged over one cycle of the sinusoid). Slowly adapting afferents (SAs), rapidly adapting afferents (RAs), and Pacinian afferents (PCs) all showed a marked increase in response when groove width increased. An increase in ridge width had no consistent effect on the responses of SAs or RAs but resulted in a small decrease in the response of PCs. The response to a smooth surface differed significantly from the responses to the finer gratings only for the RAs. An alternative measure of response (the number of impulses elicited by each spatial cycle of the grating) increased with an increase in ridge width for all 3 fiber types. Thus, the large effect of groove width on perceived roughness can be accounted for by the mean cyclic discharge rate in the active afferent fibers. The smaller effect of ridge width can be accounted for by the number of impulses per spatial cycle of the grating.