Soft and Hard Tissue Augmentation with/without Polydeoxyribonucleotide for Horizontal Ridge Deficiency: A Pilot Study in a Dog Model

Purpose@#To investigate the effects of simultaneous soft and hard tissue augmentation and the addition of polydeoxyribonucleotide (PDRN) on regenerative outcomes. @*Materials and Methods@#In five mongrel dogs, chronic ridge defects were established in both mandibles. Six implants were placed in the mandible, producing buccal dehiscence defects. The implants were randomly allocated to one of the following groups: 1) control: no treatment; 2) GBR: guided bone regeneration (GBR) only; 3) GBR/PDRN: GBR+PDRN application to bone substitute particles; 4) GBR/CTG: GBR+connective tissue grafting (CTG);5) GBR/VCMX: GBR+soft tissue augmentation using volume stable collagen matrix (VCMX); and 6) group GBR/VCMX/ PDRN: GBR+VCMX soaked with PDRN. The healing abutments were connected to the implants to provide additional room for tissue regeneration. Submerged healing was achieved. The animals were euthanized after four months. Histological and histomorphometric analyses were then performed. @*Results@#Healing abutments were gradually exposed during the healing period. Histologically, minimal new bone formation was observed in the dehiscence defects. No specific differences were found between the groups regarding collagen fiber orientation and density in the augmented area. No traces of CTG or VCMX were detected. Histomorphometrically, the mean tissue thickness was greater in the control group than in the other groups above the implant shoulder (IS). Below the IS level, the CTG and PDRN groups exhibited more favorable tissue thickness than the other groups. @*Conclusion@#Failure of submerged healing after tissue augmentation deteriorated the tissue contour. PDRN appears to have a positive effect on soft tissues.

Effect of Epidermal Growth Factor with Collagen Matrix on Increasing Gingival Thickness: A Pilot Preclinical Investigation

Purpose@#To investigate the effect of epidermal growth factor (EGF) with collagen matrix (CM) for increasing gingival thickness. @*Materials and Methods@#In five mongrel dogs, bilateral gingival defects were surgically made on the maxillary canines. After two months, either a subepithelial connective tissue graft (group SCTG) or CM with EGF (0.1 ug/ml, group EGF) was grafted, and the flap was coronally positioned to cover the graft materials. The animals were sacrificed after three months. Intraoral scanning was performed for soft tissue analysis. Histologic and histomorphometric analyses were performed.Result: Two animals exhibited wound dehiscence during the healing phase, leaving three for analysis. No statistically significant difference was found in soft tissue changes (P>0.05). The level of gingival margin (GM) increased in both groups (1.02±0.74 mm in group SCTG vs. 1.24±0.83 mm in group EGF). Linear increases at the GM preaugmentation in the soft tissue profile were 1.08±0.58 mm in group SCTG and 0.96±0.73 mm in group EGF. Histomorphometric parameters (keratinized tissue height, tissue thickness, and rete peg density) were not significantly different between the groups (P>0.05). @*Conclusion@#EGF loaded onto CM led to comparable gingival phenotype enhancement to SCTG.

Implant survival and risk factor analysis in regenerated bone: results from a 5-year retrospective study

Purpose@#The aims of this study were to evaluate the 5-year cumulative survival rate (CSR) of implants placed with guided bone regeneration (GBR) compared to implants placed in native bone, and to identify factors contributing to implant failure in regenerated bone. @*Methods@#This retrospective cohort study included 240 patients who had implant placement either with a GBR procedure (regenerated bone group) or with pristine bone (native bone group). Data on demographic features (age, sex, smoking, and medical history), location of the implant, implant-specific features, and grafting procedures and materials were collected.The 5-year CSRs in both groups were estimated using Kaplan-Meier analysis. Risk factors for implant failure were analyzed with a Cox proportional hazards model. @*Results@#In total, 264 implants in the native bone group and 133 implants in the regenerated bone group were analyzed. The 5-year CSRs were 96.4% in the regenerated bone group and 97.5% in the native bone group, which was not a significant difference. The multivariable analysis confirmed that bone status was not an independent risk factor for implant failure. However, smoking significantly increased the failure rate (hazard ratio, 10.7; P=0.002). @*Conclusions@#The 5-year CSR of implants placed in regenerated bone using GBR was comparable to that of implants placed in native bone. Smoking significantly increased the risk of implant failure in both groups.

Implant survival and risk factor analysis in regenerated bone: results from a 5-year retrospective study

Purpose@#The aims of this study were to evaluate the 5-year cumulative survival rate (CSR) of implants placed with guided bone regeneration (GBR) compared to implants placed in native bone, and to identify factors contributing to implant failure in regenerated bone. @*Methods@#This retrospective cohort study included 240 patients who had implant placement either with a GBR procedure (regenerated bone group) or with pristine bone (native bone group). Data on demographic features (age, sex, smoking, and medical history), location of the implant, implant-specific features, and grafting procedures and materials were collected.The 5-year CSRs in both groups were estimated using Kaplan-Meier analysis. Risk factors for implant failure were analyzed with a Cox proportional hazards model. @*Results@#In total, 264 implants in the native bone group and 133 implants in the regenerated bone group were analyzed. The 5-year CSRs were 96.4% in the regenerated bone group and 97.5% in the native bone group, which was not a significant difference. The multivariable analysis confirmed that bone status was not an independent risk factor for implant failure. However, smoking significantly increased the failure rate (hazard ratio, 10.7; P=0.002). @*Conclusions@#The 5-year CSR of implants placed in regenerated bone using GBR was comparable to that of implants placed in native bone. Smoking significantly increased the risk of implant failure in both groups.

Primary stability of implants with peri-implant bone defects of various widths: an in vitro investigation

PURPOSE: This study aimed to evaluate the effects of i) the extent of peri-implant bone defects and ii) the application of bone cement on implant stability with respect to the measurement direction. METHODS: In 10 bovine rib bones, 4 implant osteotomies with peri-implant bone defects of various widths were prepared: i) no defect (D0), ii) a 2-mm-wide defect (D2), iii) a 4-mm-wide defect (D4), and iv) a 8-mm-wide defect (D8). The height of all defects was 10 mm. Implant stability quotient (ISQ) values and Periotest values (PTVs) were measured after implant placement and bone cement application. RESULTS: With increasing defect width, decreased ISQs and increased PTVs were observed. Statistically significant differences were found between groups D0 and D8, D0 and D4, and D2 and D8. Prior to bone cement application, inconsistent PTVs were found in group D8 depending on the measurement direction. Bone cement increased the implant stability. CONCLUSION: Peri-implant bone deficits measuring around 50% of the implant surface compromised implant stability. Clinically, PTVs should be cautiously interpreted in implants with large peri-implant defects due to inconsistent recordings with respect to the measurement direction.

Cone-beam computed tomographic analysis of the alveolar ridge profile and virtual implant placement for the anterior maxilla

PURPOSE: To analyze the ridge profile of the anterior maxilla using cone-beam computed tomography and to assess the clinical significance of the ridge profile by performing virtual implant placement. METHODS: Thirty-two cone-beam computed tomography scans of anterior maxillae were included. For each tooth, a vertical line was made along the longitudinal axis, and 3 horizontal lines at 1-, 3-, and 5-mm levels below the labial bone crest were drawn perpendicularly to the vertical reference. At these levels, the thickness of the alveolar ridge (RT), and the labial (LT) and palatal bone plate (PT) were measured. Then, virtual implant placement using standard and tapered implants was performed. A generalized linear mixed model was used for statistical analysis. RESULTS: The teeth were located labially based on the proportion of LT and PT with respect to RT. At the 1-mm level, the value of LT was between 1.0±0.4 mm for central incisors and 1.3±0.6 mm for canines. A large number of teeth had area(s) with less than 1-mm-thick labial bone between the 1- and 5-mm levels below the crest. The mean PT was generally thicker than the LT in all tooth types. The greatest mean value of labial concavity was observed for canines, compared to other tooth types. Men had a greater RT than did women, but had a comparable LT. Less apical fenestration was observed when tapered implants were used. CONCLUSIONS: Most teeth in the anterior maxilla had a thin labial bone plate, with no significant difference between sexes. Tapered implants may be advantageous for the anterior maxilla.

Primary implant stability in a bone model simulating clinical situations for the posterior maxilla: an in vitro study

PURPOSE: The aim of this study was to determine the influence of anatomical conditions on primary stability in the models simulating posterior maxilla. METHODS: Polyurethane blocks were designed to simulate monocortical (M) and bicortical (B) conditions. Each condition had four subgroups measuring 3 mm (M3, B3), 5 mm (M5, B5), 8 mm (M8, B8), and 12 mm (M12, B12) in residual bone height (RBH). After implant placement, the implant stability quotient (ISQ), Periotest value (PTV), insertion torque (IT), and reverse torque (RT) were measured. Two-factor ANOVA (two cortical conditions×four RBHs) and additional analyses for simple main effects were performed. RESULTS: A significant interaction between cortical condition and RBH was demonstrated for all methods measuring stability with two-factor ANOVA. In the analyses for simple main effects, ISQ and PTV were statistically higher in the bicortical groups than the corresponding monocortical groups, respectively. In the monocortical group, ISQ and PTV showed a statistically significant rise with increasing RBH. Measurements of IT and RT showed a similar tendency, measuring highest in the M3 group, followed by the M8, the M5, and the M12 groups. In the bicortical group, all variables showed a similar tendency, with different degrees of rise and decline. The B8 group showed the highest values, followed by the B12, the B5, and the B3 groups. The highest coefficient was demonstrated between ISQ and PTV. CONCLUSIONS: Primary stability was enhanced by the presence of bicortex and increased RBH, which may be better demonstrated by ISQ and PTV than by IT and RT.

Survival of 352 titanium implants placed in 181 patients: a 4-year multicenter field study

PURPOSE: The aim of this retrospective chart review was to evaluate the four-year survival rate of a titanium implant system. METHODS: A total of 352 sand-blasted, thermally acid-etched titanium implants were inserted into 181 partially or completely edentulous patients. Their cumulative survival rate was evaluated retrospectively. Associated factors, such as the implant distribution and treatment type were included in the evaluation. RESULTS: The implants were equally distributed between the maxilla (52.3%) and the mandible (47.7%). 48 implants (13.6%) were placed in the anterior region and 304 implants (86.4%) in the posterior region. The majority of the implants were inserted into bone of type II and III quality (89.8%) and volume (quantity B and C, 87.2%). Most of the implants (70.7%) were restored as single crowns; 28.7% supported a bridge construction and 0.6% a full denture. Only one implant failed, resulting in a four-year cumulative survival rate of 99.7%. CONCLUSIONS: The implant system showed an excellent four-year survival rate. It proved to be a safe and predictable means for restoration of the dentition in partially or completely edentulous patients.

Effect of erbium-doped: yttrium, aluminium and garnet laser irradiation on the surface microstructure and roughness of sand-blasted, large grit, acid-etched implants

PURPOSE: The present study was performed to evaluate the effect of erbium-doped: yttrium, aluminium and garnet (Er:YAG) laser irradiation on sand-blasted, large grit, acid-etched (SLA) implant surface microstructure according to varying energy levels and application times of the laser. METHODS: The implant surface was irradiated by the Er:YAG laser under combined conditions of 100, 140, or 180 mJ/pulse and an application time of 1 minute, 1.5 minutes, or 2 minutes. Scanning electron microscopy (SEM) was used to examine the surface roughness of the specimens. RESULTS: All experimental conditions of Er:YAG laser irradiation, except the power setting of 100 mJ/pulse for 1 minute and 1.5 minutes, led to an alteration in the implant surface. SEM evaluation showed a decrease in the surface roughness of the implants. However, the difference was not statistically significant. Alterations of implant surfaces included meltdown and flattening. More extensive alterations were present with increasing laser energy and application time. CONCLUSIONS: To ensure no damage to their surfaces, it is recommended that SLA implants be irradiated with an Er:YAG laser below 100 mJ/pulse and 1.5 minutes for detoxifying the implant surfaces.

A comparison of different gingival depigmentation techniques: ablation by erbium:yttrium-aluminum-garnet laser and abrasion by rotary instruments

PURPOSE: The aim of this study is to compare two different gingival depigmentation techniques using an erbium:yttrium-aluminum-garnet (Er:YAG) laser and rotary instruments. METHODS: Two patients with melanin pigmentation of gingiva were treated with different gingival depigmentation techniques. Ablation of the gingiva by Er:YAG laser was performed on the right side, and abrasion with a rotary round bur on the opposite side. RESULTS: The patients were satisfied with the esthetically significant improvement with each method. However, some pigment still remained on the marginal gingival and papilla. The visual analog scale did not yield much difference between the two methods, with slightly more pain on the Er:YAG laser treated site. CONCLUSIONS: The results of these cases suggest that ablation of the gingiva by an Er:YAG laser and abrasion with a rotary round bur is good enough to achieve esthetic satisfaction and fair wound healing without infection or severe pain. Prudent care about the gingival condition, such as the gingival thickness and degree of pigmentation along with appropriate assessment is needed in ablation by the Er:YAG laser procedure.

Tissue reactions to suture materials in the oral mucosa of beagle dogs

PURPOSE: The objective of this study was to compare and evaluate the inflammatory responses of three widely used suture materials in the keratinized gingiva and buccal mucosa of beagle dogs. METHODS: Silk, polyglycolic acid, and nylon sutures were placed within the mandibular keratinized gingiva and maxillary buccal mucosa of four male beagle dogs. Biopsies were taken 3, 7, and 14 days after suturing. Specimens were prepared with hematoxylin-eosin stain for evaluation under a light microscope. RESULTS: The suture materials placed in the oral mucosa elicited more inflammatory reactions than did those placed in the keratinized gingiva. The multifilament suture materials caused more inflammatory tissue reactions than did the monofilament suture materials in the oral mucosa. CONCLUSIONS: If oral hygiene is well maintained and suture materials are placed in the keratinized gingiva, silk, nylon, and polyglycolic acid are considered to be proper suture materials for oral surgery. However, it is advisable to use monofilament suture materials if the suture site is within the oral mucosa.

The effect of erbium-doped: yttrium, aluminium and garnet laser irradiation on the surface microstructure and roughness of double acid-etched implants

PURPOSE: One of the most frequent complications related to dental implants is peri-implantitis, and the characteristics of implant surfaces are closely related to the progression and resolution of inflammation. Therefore, a technical modality that can effectively detoxify the implant surface without modification to the surface is needed. The purpose of this study was to evaluate the effect of erbium-doped: yttrium, aluminium and garnet (Er:YAG) laser irradiation on the microstructural changes in double acid-etched implant surfaces according to the laser energy and the application duration. METHODS: The implant surface was irradiated using an Er:YAG laser with different application energy levels (100 mJ/pulse, 140 mJ/pulse, and 180 mJ/pulse) and time periods (1 minute, 1.5 minutes, and 2 minutes). We then examined the change in surface roughness value and microstructure. RESULTS: In a scanning electron microscopy evaluation, the double acid-etched implant surface was not altered by Er:YAG laser irradiation under the condition of 100 mJ/pulse at 10 Hz for any of the irradiation times. However, we investigated the reduced sharpness of the specific ridge microstructure that resulted under the 140 mJ/pulse and 180 mJ/pulse conditions. The reduction in sharpness became more severe as laser energy and application duration increased. In the roughness measurement, the double acid-etched implants showed a low roughness value on the valley area before the laser irradiation. Under all experimental conditions, Er:YAG laser irradiation led to a minor decrease in surface roughness, which was not statistically significant. CONCLUSIONS: The recommended application settings for Er:YAG laser irradiation on double acid-etched implant surface is less than a 100 mJ/pulse at 10 Hz, and for less than two minutes in order to detoxify the implant surface without causing surface modification.

Clinical treatment of postoperative infection following sinus augmentation

PURPOSE: The aim of this case report is to present the successful clinical treatment of two cases of postoperative infection following maxillary sinus augmentation. METHODS: In the two cases of postoperative infection, immediate total removal of the grafted material from the sinus was conducted to stop the spread of the infection, after which a high dose of antibiotics was administrated. Re-augmentation procedures were then conducted after the infection subsided. RESULTS: No further complications occurred after sinus re-augmentation. The dental implants placed in the re-augmented sinus were clinically osseointegrated, and the implant-supported restorations in the two cases of postoperative infection have been functioning very well for over 2 years. CONCLUSIONS: In the case of infection of the grafted sinuses, it is necessary to completely remove the graft materials and then administer a high dose of antibiotics to treat the acute infection, after which sinus re-augmentation is suggested.

I-shaped incisions for papilla reconstruction in second stage implant surgery

PURPOSE: Pink gingival esthetic especially on the anterior teeth has been an important success criterion in implant-supported restoration. Inter-implant papillae are a critical factor for implant esthetics, and various techniques for inter-implant papilla reconstruction have been introduced. The aim of this study is to suggest and evaluate a surgical technique for reconstructing inter-implant papillae. METHODS: A 28-year-old man had an implant placed on the #13 and #14 area. Four months after implant placement, a second stage surgery was planned for inter-implant papilla reconstruction. At the time of the abutment connection, I-type incisions were performed on the #13i & #14i area followed by full-thickness flap elevation and connection of a healing abutment on underlying fixtures without suture. RESULTS: Two weeks after the second stage implant surgery, soft tissue augmentation between the two implants was achieved. CONCLUSIONS: I-shaped incisions for papilla reconstruction performed during the second stage implant surgery were useful for inter-implant papilla reconstruction and showed a good esthetic result.

Implant failure associated with oral bisphosphonate-related osteonecrosis of the jaw

PURPOSE: The aim of this study is to report a case of oral bisphosphonate-related osteonecrosis of the jaw (BRONJ) resulting in implant failure. METHODS: A patient suspected of having BRONJ was referred to the Department of Periodontology, Kyung Hee University School of Dentistry for the evaluation and treatment of exposed bone around implants. RESULTS: The patient, who had been taking oral bisphosphonates (BPs) for about a year, was successfully treated with systemic antibiotics, chlorhexidine mouth rinse, explantation, and surgical debridement of necrotic bone. CONCLUSIONS: The results of this case suggest that a patient taking BPs orally should be treated cautiously. Appropriate management including cessation of BPs and respective dental treatment may reduce the development of BRONJ.

Incomplete bone formation after sinus augmentation: A case report on radiological findings by computerized tomography at follow-up

PURPOSE: The aim of this case report is to present a case of incomplete bone formation after sinus augmentation. METHODS: A patient having alveolar bone resorption of the maxillary posterior edentulous region and advanced pneumatization of the maxillary sinus was treated with sinus elevation using deproteinized bovine bone in the Department of Periodontology, Kyung Hee University School of Dentistry and re-evaluated with computed tomography (CT) follow-up. RESULTS: Even though there were no significant findings or abnormal radiolucency on the panoramic radiograph, incomplete bone formation in the central portion of the augmented sinus was found fortuitously in the CT scan. The CT scan revealed peri-implant radiolucency in the apical portion of the implant placed in the augmented maxillary sinus. Nevertheless, the dental implants placed in the grafted sinus still functioned well at over 15 months follow-up. CONCLUSIONS: The result of this case suggests that patients who received maxillary sinus augmentation may experience incomplete bone formation. It is possible that 1) osteoconductive graft material with poor osteogenic potential, 2) overpacking of graft material that restricts the blood supply, and 3) bone microbial contamination may cause the appearance of incomplete bone formation after sinus augmentation. Further studies are needed to elucidate the mechanism of this unexpected result and care must be taken to prevent it.

The effect of Er:YAG laser irradiation on the surface microstructure and roughness of hydroxyapatite-coated implant

PURPOSE: The present study was performed to evaluate the effect of erbium:yttrium-aluminium-garnet (Er:YAG) laser irradiation on the change of hydroxyapatite (HA)-coated implant surface microstructure according to the laser energy and the application time. METHODS: The implant surface was irradiated by Er:YAG laser under combination condition using the laser energy of 100 mJ/pulse, 140 mJ/pulse and 180 mJ/pulse and application time of 1 minute, 1.5 minutes and 2 minutes. The specimens were examined by surface roughness evaluation and scanning electron microscopic observation. RESULTS: In scanning electron microscope, HA-coated implant surface was not altered by Er:YAG laser irradiation under experimental condition on 100 mJ/pulse, 1 minute. Local areas with surface melting and cracks were founded on 100 mJ/pulse, 1.5 minutes and 2 minutes. One hundred forty mJ/pulse and 180 mJ/pulse group had surface melting and peeling area of HA particles, which condition was more severe depending on the increase of application time. Under all experimental condition, the difference of surface roughness value on implant surface was not statistically significant. CONCLUSIONS: Er:YAG laser on HA-coated implant surface is recommended to be irradiated below 100 mJ/pulse, 1 minute for detoxification of implant surface without surface alteration.

The effects of hydroxyapatite toothpaste on tooth hypersensitivity / 대한치주과학회지

PURPOSE: The present study was performed to evaluate the effect of hydroxyapatite dental paste on tooth hypersensitivity compared to other materials. MATERIALS AND METHODS: In the general fluoride dental paste, strontium fluoride dental paste and hydroxyapatite dental paste, patient-performed VAS and VAS(ice test) were measured at baseline, 1weeks and 4weeks. RESULTS: 1. In patient-performed VAS, there were significant differences reducing of tooth hypersensitivity between general fluoride toothpaste and hydroxyapatite toothpaste. 2. In operator-performed VAS(ice test), there were significant differences reducing of tooth hypersensitivity among each group, between general fluoride toothpaste and hydroxyapatite toothpaste and between general fluoride toothpaste and strontium fluoride toothpaste. CONCLUSION: In conclusion, hydroxyapatite toothpaste can be applied for control of tooth hypersensitivity.

The evaluation of clinical outcomes on various procedures using subepithelial connective tissue graft for coverage of gingival recession / 대한치주과학회지

PURPOSE: The subepithelial connective tissue graft(SCTG) has been proven to be a highly predictable treatment modality for coverage of gingival recession. This case report was performed to evaluate the effect of various root coverage procedures using SCTG on gingival recession. MATERIALS AND METHODS: Three patients presents with Miller's class I recession defect on the maxillary canine. Each other SCTG(coronally advanced flap, Bruno's Tech., envelope Tech.) were performed for root coverage. Clinical parameters assessed included recession depth, recession width, and keratinized gingival width. Measurements were taken at baseline and 2 months and follow up end. RESULTS: The average of root coverage was 4 mm(100% of the pre-operative recession depth) at the 2, 5 months examination. The average increase of keratinized tissue between the baseline and the 2 months amounted to 3.2mm. CONCLUSION: Within the above results, various root coverage using SCTG is an effective procedure to Miller's class I recession defect and patient could be satisfied aesthetic requirement.

Root coverage using subepithelial connective tissue graft / 대한치주과학회지

PURPOSE: One of the main objectives of periodontal reconstructive surgery is the coverage of exposed roots that occur due to gingival recession. and Aestheic concerns are usually the reason to perform root coverage procedure. This case report was performed to evaluate the effect of root coverage using subepithelial connective tissue graft(SCTG) on Miller's Class I marginal tissue recession. MATERIALS AND METHODS: One patient, with two Miller's class I marginal tissue recession on both maxiallay canines, was treated with root coverage using SCTG (modified Nelson's technique). At baseline, the following measurements were recorded: 1) recession depth; 2) width of keratinized giniga. At 9, 10 months post-surgery, all clinical measurements were repeated. RESULT: 1) The mean root coverage from baseline to 9, 10 months post-surgery was 92.3%. 2) The mean recession depth decreased from 6.5 mm to 0.5 mm. 3) The mean width of keratinized gingiva increased from 1.25 mm to 3.5 mm. CONCLUSION: Within the above results, root coverage using SCTG is an effective procedure to cover Miller's class I marginal tissue recession defect. Also, patient with aesthetic concern could be satisfied with this result.