Time management in multistep periodontal and implant treatments: a practical guide

In addition to the proper selection of techniques, appropriate treatment sequencing and prioritization are prerequisites for successful periodontal and implant procedures. The aim of this study was to provide evidence-based time frames for various procedures pertaining to periodontal and implant treatment. A literature review was conducted to collect data on tissue healing; in areas in which data were lacking, the viewpoints of experienced clinicians were solicited to establish a consensus. This review reports recommended time frames for the healing processes associated with surgical crown-lengthening procedures (both functional and esthetic), fresh socket management, alveolar ridge management, soft tissue management, sinus floor augmentation, implant loading, and peri-implant defect management.

Clinical efficacy of intraoral ultrasonography versus transgingival probing for measurement of gingival thickness in different gingival biotypes: a clinical trial

BACKGROUND

Transgingival probing is conventionally used for gingival thickness (GT) measurement. However, invasiveness is a major drawback of transgingival probing. Thus, researchers have been in search of alternative methods for measurement of GT. This study compared the clinical efficacy of intraoral ultrasonography and transgingival probing for measurement of GT in different biotypes.

MATERIALS AND METHODS

This clinical trial was conducted on 34 patients requiring crown lengthening surgery. GT was measured at 40 points with 2- and 4-mm distances from the free gingival margin (FGM) of anterior and premolar teeth of both jaws in each patient by an intraoral ultrasound probe. For measurement of GT by the transgingival probing method, infiltration anesthesia was induced, and a #25 finger spreader (25 mm) was vertically inserted into the soft tissue until contacting bone. The inserted length was measured by a digital caliper with 0.01 mm accuracy. All measurements were made by an operator with high reliability under the supervision of a radiologist. Data were analyzed by t-test, Power and Effect Size formula, and intraclass correlation coefficient (ICC).

RESULTS

The two methods were significantly different in measurement of GT in both thick and thin biotypes at 2- and 4-mm distances (P < 0.001). The two methods had a significant difference in both the mandible (P < 0.001) and maxilla (P < 0.001) and in both the anterior (P < 0.003) and premolar (P < 0.003) regions. Although the difference was statistically significant in t-tests, the power and effect formula proved it to be clinically insignificant. Also, the ICC of the two methods revealed excellent agreement.

CONCLUSION

The results showed optimal agreement of ultrasound and transgingival probing for measurement of GT.

TRIAL REGISTRATION

The study was approved by the ethics committee of Shahid Beheshti University of Medical Sciences on 2021-12-28 (IR.SBMU.DRC.REC.1400.138) and registered in the Iranian Registry of Clinical Trials on 2022-03-14 (IRCT20211229053566N1).

Periodontal phenotype modification in orthodontic patients

OBJECTIVE

The purpose of this study was to assess the feasibility of phenotype modification in orthodontic patients using combined bone and soft tissue grafting substitutes.

CLINICAL CONSIDERATION

The surgical procedure was conducted on 18 patients (3 males, 15 females). Periodontal phenotype modification was conducted using demineralized freeze-dried bone allograft and a xenogeneic collagen matrix. The following parameters were recorded for each tooth at baseline and 12-month follow-up: O'Leary plaque index (PI), probing depth (PD), bleeding on probing (BOP), gingival thickness (GT), keratinized tissue width (KTW), gingival recession (GR), and vestibular depth (VD). The results showed a statistically significant increase in GT (2.02 ± 0.39 mm), KTW (1.11 ± 0.82 mm), and VD (0.18 ± 1.16 mm) (p < 0.05). GR was also significantly decreased (1.02 ± 0.99 mm) (p < 0.05).

CONCLUSION

Within the limitation of this study, the proposed approach enhanced the periodontal condition in orthodontic patients. However, further studies with a larger sample size are needed to ensure long-term stability.

CLINICAL SIGNIFICANCE

Hard and soft tissue conditions have paramount importance for long-term periodontal stability. Phenotype modification in orthodontic patients can diminish the probability of adverse consequences and result in optimal esthetic outcomes. The proposed technique using combined bone and soft tissue substitutes indicated promising results and could be recommended in orthodontic patients with thin periodontal phenotypes.

Comparison of the Volume and Histological Properties of Newly Formed Bone after the Application of Three Types of Bone Substitutes in Critical-Sized Bone Defects

This study aimed to compare the volume and quality of the newly formed bone following application of two types of xenografts and one synthetic material in bone defects in rabbit calvaria from histological and micro-CT aspects. Four 8-mm defects were created in 12 rabbit calvaria. Three defects were filled with bone substitutes and one was left unfilled as the control group. The newly formed bone was evaluated histologically and also by micro-CT at 8 and 12 weeks after the intervention. The percentage of osteogenesis was comparable in histomor-phometric assessment and micro-CT. Histological analysis showed that the percentage of the newly formed bone was 10.92 ± 5.17%, 14.70 ± 11.02%, 11.47 ± 7.04%, and 9.45 ± 5.18% in groups bovine 1, bovine 2, synthetic, and negative control, respectively after 8 weeks. These values were 33.70 ± 11.48%, 26.30 ± 18.05%, 22.92 ± 6.30%, and 14.82 ± 8.59%, respectively at 12 weeks. The difference in the percentage of the new bone formation at 8 and 12 weeks was not significant in any group (P > 0.05) except for bovine 1 group (P < 0.05). Micro-CT confirmed new bone formation in all groups but according to the micro-CT results, the difference between the control and other groups was significant in this respect (P < 0.05). All bone substitutes enhanced new bone formation compared with the control group. Micro-CT assessment yielded more accurate and different results compared with histological assessment.

Evaluation of matrix metalloproteinase-1, -2, -3, -7, and -13 gene polymorphisms in patients with chronic periodontitis and healthy controls

OBJECTIVES

The current study aimed to investigate the association of matrix metalloproteinase- (MMP-) 1, -2, -3, -7, and -13 gene polymorphisms with chronic periodontitis (CP) in an Iranian population.

MATERIALS AND METHODS

In this case-control study, 87 subjects with CP and 89 periodontally healthy subjects were allocated to case and control groups, respectively. Subjects' venous blood samples (5 cc) were collected, and DNA extraction was performed. A spectrophotometer was utilized to assess the concentration of extracted DNAs. The desired gene polymorphisms were examined using restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) followed by electrophoresis. Statistical analyses were done using the Pearson Chi-Square test, odds ratio, and t-Test using SPSS Version 28.

RESULTS

The MMP-1 (-1607 1G/2G) rs1799750, MMP-3 (-1171 5A/6A) rs3025058, and MMP-7 (-181 A/G) rs11568818 gene polymorphisms significantly differed between case and control groups (PV = 0.019, 0.007, and 0.028, respectively). In contrast, the gene polymorphisms of MMP-2 (-1306 C/T) rs243865 and MMP-13 (-77 A/G) rs2252070 did not make a significant difference. Regarding allele frequencies, the presence of the 2G allele in the MMP-1 (-1607) rs1799750 genotype increased the CP susceptibility significantly, while subjects with the 6A allele in their MMP-3 (-1171) rs3025058 genotype showed significantly lower susceptibility to CP (PV = 0.008 and < 0.001, respectively).

CONCLUSION

In the studied population, gene polymorphisms in the DNA sequences of MMP-1 (-1607 1G/2G) rs1799750, MMP-3 (-1171 5A/6A) rs3025058, and MMP-7 (-181 A/G) rs11568818 may have impacts on CP incidence.

CLINICAL RELEVANCE

Clinicians should be cautious about the association between MMP-1, MMP-3, and MMP-7 gene polymorphisms and the incidence of chronic periodontitis during periodontal treatment planning.

Immediate implant placement in compromised sockets: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Immediate implant placement provides a popular therapeutic option. However, compromised sockets may jeopardize the treatment outcome.

PURPOSE

The purpose of this systematic review and meta-analysis was to investigate the treatment outcome in terms of the implant survival rate and success parameters of immediate implant placement in compromised extraction sockets.

MATERIAL AND METHODS

An electronic search was conducted in PubMed, Embase, Cochrane Library, and ISI Web of Science up to January 2021. Studies evaluating implant survival rate and main success parameters were included for a qualitative and quantitative analysis (risk ratio and mean difference).

RESULTS

In total, 43 studies with analysis of 4825 sockets were included. Compared with the noncompromised sockets, the compromised group showed no significant differences in implant survival rates (risk ratio=0.992; 95% confidence interval (CI)=0.979 to 1.005; P=.246). No significant statistical differences were found in marginal bone level at ≤12 months (mean difference [MD]=0.033; 95% CI=-0.012 to 0.078; P=.154) or esthetic parameters.

CONCLUSIONS

Immediate implant placement in compromised sites does not appear to decrease the survival and success rates. However, randomized clinical trials with large sample sizes should be conducted to draw a definite conclusion about the efficacy and safety of this treatment protocol in compromised sockets.

Short-term and long-term success and survival rates of implants supporting single-unit and multiunit fixed prostheses: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Whether placing implants to replace each missing tooth or using implant-supported fixed partial dentures provides better outcomes is unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to assess the success and survival rates of implants supporting single-unit and multiunit fixed prostheses by using conventional protocols for placement and loading in short- and long-term follow-ups.

MATERIAL AND METHODS

An electronic search was conducted in PubMed, Scopus, and Web of Science for studies published up to March 17, 2022. Comparative studies that reported the success or survival rates of both single-unit and splinted multiunit prostheses were considered for qualitative and quantitative analyses.

RESULTS

A total of 68 publications comprising 11 271 implants were included. Compared with the single prostheses, the splinted multiunit group showed no significant differences in implant success rates in the short-term (risk difference=-0.004; 95% confidence interval (CI)=-0.033 to 0.025; P=.780) and long-term (risk difference=0.003; 95% confidence interval (CI)=-0.029 to 0.034; P=.874) follow-ups. Significant statistical differences were also not found in terms of the survival rates of the 2 groups (short-term risk difference=-0.004; 95% CI=-0.031 to 0.023; P=.779, long-term risk difference=-0.002; 95% CI=-0.029 to 0.025; P=.887).

CONCLUSIONS

Implants supporting single-unit or splinted multiunit prostheses seem to be a predictable treatment in terms of survival and success over short and long periods. Nonetheless, it seems that cantilever and nonsplinted multiunit prostheses should be used with more caution.

Evaluation of interleukin 10, interleukin 1-beta, and tumor necrosis factor-alpha gene polymorphisms in patients with periodontitis and healthy controls

Background

Chronic periodontitis (CP) is a prevalent infectious disease caused by an interplay between pathogens and immune responses. Gene polymorphisms are among the factors that affect susceptibility to CP. This study aimed to assess the association between CP and single nucleotide polymorphisms (SNPs) of interleukin-10 (IL-10), interleukin 1ß (IL-1ß), and tumor necrosis factor-α (TNF-α) genes.

Methods

A total of 87 patients with CP and 89 healthy controls were included in this study. Venous blood samples were obtained, and DNA was extracted and purified. Segments containing the relevant genes were amplified by polymerase chain reaction (PCR). Electrophoresis was performed after restriction fragment length polymorphism (RFLP) to determine genotype and allele frequencies.

Results

The CP group showed significantly different allele and genotype frequencies for three out of five SNPs: IL-10 ─ 592 C/A, IL-10 ─ 819 C/T, and IL-1ß + 3954 C/T (p < 0.05). Additionally, the frequency of the TNF-α ─ 857 AA genotype was significantly lower in patients compared with controls (p = 0.034); however, no significant differences were found in allele frequencies (p > 0.05). Logistic regression analysis revealed that carriers of IL-10 ─ 592 A allele and IL-1ß + 3954 T allele are at higher risk of CP (p < 0.001). Allele and genotype frequencies for TNF-α ─ 308 G/A did not differ significantly between patients and controls (p > 0.05).

Conclusions

This study showed specific genotypes of IL-10 ─ 592 C/A, IL-10 ─ 819 C/T, IL-1ß + 3954 C/T, and TNF-α ─ 857 G/A SNPs may be associated with an increased risk of CP development.

Soft and Hard Tissue Changes Subsequent to Spontaneous Healing of the Extraction Sockets Using Cone-Beam Computed Tomography: A Cross-Sectional Study

Objective

This study sought to compare the thickness of hard and soft tissues between edentulous and contralateral tooth sites.

Materials and Methods

This split-mouth study evaluated 153 partially edentulous patients. The measurements were made on cone-beam computed tomography (CBCT) scans. The soft tissue thickness was measured at the cementoenamel junctional (CEJ) level, and at 2, 4, and 6 mm apical to the CEJ in the facial and palatal aspects. The bone thickness of the opposite quadrant was also recorded at 2, 4, and 6 mm apical to the CEJ. The Mann-Whitney U test and the Spearman's rank correlation coefficient were applied for further statistical analyses.

Results

At the edentulous sites, significant soft tissue loss was noted at the CEJ level (p < 0.0001) and a considerable gain was noted at 2, 4, and 6 mm apical to the CEJ (p = 0.004, p < 0.0001, p ≤ 0.0001, respectively). A significant hard tissue loss was noted at 2 mm apical to the CEJ but a significant hard tissue gain was observed at the edentulous sites (p < 0.0001). The soft tissue gain at 6 mm apical to the CEJ was significantly associated with an increase in buccolingual diameter (p = 0.004) while the hard tissue loss at 2 mm apical to the CEJ was significantly correlated with a reduction in buccolingual diameter (p = 0.020).

Conclusion

Different amounts of tissue thickness alterations occurred in different levels of socket.

Determination of the Volume and Density of Mandibular Ramus as a Donor Site Using CBCT

Introduction

This study aimed to assess the quantity and quality of available bone to provide the autologous bone graft from mandibular ramus.

Material and Methods

CBCT scans were collected and mandibular ramus was evaluated by measuring a variety of parameters including volume, bone height, cortical, and cancellous bone thickness. Data analysis was performed using descriptive statistics and inferential statistics. We used the Kolmogorov-Smirnov test for the evaluation of data normality. We then applied Pearson correlation and independent t-test for normal variables, and Spearman and Mann-Whitney correlation tests for abnormal variables. Statistical analysis was performed using SPSS version 19 and P value < 0.05 was considered significant.

Results

A total of 52 women and 32 men (aged 21 to 70) were included in this study. The mean bone volume was 2.7 ± 0.70 cm3 [95%confidence interval (CI) 1.3-4.5]. The mean bone density in the middle section was 1016.36 ± 231.58 Gy value (95% CI 475.6-1520.9). Kolmogorov-Smirnov test revealed that the variables such as apical cortical/cancellous ratio (P = 0.005), middle-cancellous bone thickness (P = 0.016), and middle cortical/cancellous ratio (P = 0.005) were abnormal and the rest were normal. Bone density, as well as the amount of cortical bone in the middle and apical regions, had a significant reverse correlation with age (P < 0.001).

Conclusion

The volume, density, and cortical/cancellous ratio are independent of sex. The reverse relationship between age and bone density, as well as the amount of cortical bone in several parts, indicates a decrease in bone quality with aging.

A systematic scoring system to determine the long-term prognosis for severely damaged teeth

Many of the criteria commonly considered in treatment planning for severely damaged teeth are well known to clinicians. However, a systematic approach to decision-making is lacking. The purpose of this article is to introduce a quantitative systematic risk assessment scoring system (RASS) to determine the long-term prognosis for severely damaged teeth based on several important factors. Before any treatment decision is made, the dentist should take into account the role of systemic parameters such as the medical condition of the patient, smoking status, psychological factors, patient expectations with regard to the duration and overall cost of treatment, and periodontal health. In the assessment of local factors, emphasis should be placed on 5 parameters: crown to root ratio, root condition, risk of furcation involvement, complexity of the final restoration, and esthetic results. In the proposed RASS, each of these parameters is ranked using 4 color-coded levels of risk: optimal (green), favorable (blue), unfavorable (yellow), or hopeless (red). The presence of even 1 parameter in the red zone is sufficient to consider tooth extraction. If no parameter is in the red zone, the final decision should be made after the possible effects of all of the clinical conditions are weighed and the overall risk of treatment failure is determined. Clinical decision-making with regard to the preservation or extraction of severely damaged teeth is a challenging, multifactorial process. The RASS introduced in this article focuses on 5 main factors to simplify and organize the decision-making process; however, many other parameters may affect the final treatment decision. Moreover, no decision-making system can be definitively applied to all clinical scenarios, and the entire process depends on the knowledge, experience, and expertise of the clinician.

A comparison of human dental pulp stem cell activity cultured on sandblasted titanium discs decontaminated with Er:YAG laser and air-powder abrasion: an in vitro study

Decontamination of implant surfaces is important to the treatment of peri-implantitis. Er:YAG laser and air-powder abrasion system are regarded as the most effective means of decontamination of implant surfaces. The aim of this in vitro study was to compare the activity of human dental pulp stem cells (hDPSCs) cultured on decontaminated sandblasted titanium discs using Er:YAG laser irradiation and air-powder abrasion. Forty-five titanium discs were contaminated with Escherichia coli (E. coli) bacteria and fifteen titanium discs served as sterile control groups. Thirty contaminated titanium discs were decontaminated with Er:YAG laser or air-powder abrasion system and fifteen contaminated discs were used as contaminated control group. Afterwards, hDPSCs were seeded on all sixty experimental titanium discs. The effects of two decontamination tools on hDPSCs viability were evaluated by MTT assay. Alkaline phosphatase (ALP) activity assay, quantitative real-time PCR analysis and alizarin red staining method were performed to assess hDPSCs osteogenic differentiation. Scanning microscope electron (SEM) was also used to evaluate the effects of two different decontaminated methods on cellular morphology. Our study showed that decontamination using Er:YAG laser caused maximum cell viability. However, the ALP activity was not different in laser and air-abrasion groups. The significant expression of an osteoblastic marker and stronger Alizarin red staining were observed in laser irradiation groups. In addition, SEM observation indicated that grown cells were more stretched and more filopodia in Er:YAG-treated discs. In the present study, Er:YAG laser and air-powder abrasion improved the activity of the cells cultured on the decontaminated titanium discs. However, in comparison with air-powder abrasion, Er:YAG laser was more effective.

Effects of Two Protocols of Low-Level Laser Therapy on the Proliferation and Differentiation of Human Dental Pulp Stem Cells on Sandblasted Titanium Discs: An In Vitro Study

Introduction: Stem cell activities have different effects on tissue response and its outcomes. Low-level laser therapy (LLLT) can be considered a trigger to modify stem cell activities. The objective of the present experimental investigation was to study the effects of two protocols of LLLT on the proliferation and differentiation of human dental pulp stem cells (hDPSCs) cultured on sandblasted titanium discs. Methods: Cells obtained from human dental pulp were seeded/cultured on titanium discs and were set in 2 main groups: (i) Radiated cells using the gallium-aluminium-arsenide (GaAlAs) diode laser at a continuous wavelength of 808 nm at 3 J/cm² for 12 sec or 5 J/cm² for 20 seconds, and (ii) Non-irradiated cells serving as control groups. The impact of LLLTs on hDPSC-proliferation and viability was investigated using the MTT assay after 24, 72 and 96 hours. The alkaline phosphatase activity was studied with p-nitrophenylphosphate after 14 and 28 days. The ability of hDPSCs to express osteocalcin was investigated using real-time polymerase chain reaction after 28 days, while their attachment was observed under a scanning electron microscope (SEM) after 14 and 28 days. Results: Our study showed that LLLTs caused maximum cell proliferation in 96 hours (P<0.001) with 3 J/cm² resulting in a higher proliferation rate. The highest activity of alkaline phosphatase and osteocalcin expression was observed in the laser radiation groups after 28 days. Conclusion: The outcomes of the current study showed that cultured hDPSCs on sandblasted titanium discs had a tendency towards increased cellular activity in response to LLLTs. Thus, LLLTs could regulate the activities of hDPSCs on bone repair surrounding the sandblasted titanium discs.

CBCT Evaluation of the maxillary palatine process as a donor site for the regeneration of periodontal defects

Background

The maxillary palatine process (MPP) is an excellent source of autogenous bone transplants for anterior maxillary reconstruction. This research aimed to determine the quantity and quality of accessible MPP as a donor location.

Methods

Cone-beam computed tomography (CBCT) scans of patients referred to the School of Dentistry were evaluated by a certified examiner. The harvestable MPP was defined as the space between the distal surfaces of maxillary first premolars. OnDemand 3D Imaging software was used to determine bone properties. SPSS software was used to investigate the following variables: Bone characteristics are correlated with age and gender, accessible volume, and palatal width and height. P<0.05 was defined as the level of statistical significance.

Results

This study was performed on CBCT scans of 81 subjects (41 females and 40 males). MPP volume and palatal heights were 1.33±0.53 cm3 and 20.86±5.51 mm, respectively. Maximum bone density was observed around lateral incisors. Palatal width was 33.81±2.42 mm between canines and 41.81±2.66 mm between premolars. The MPP volume was significantly greater in males (P<0.001). Additionally, there was a positive correlation between the volume and palatal width (P<0.05).

Conclusion

Within the constraints of this research, there is a limited supply of MMP accessible for use as a graft source, and it is best suited for treating localized bone lesions. The favorable link between palatal breadth and harvestable volume aids the surgeon in estimating the quantity of bone accessible during the first evaluation.

Effect of Soft Tissue Condition on Peri-implant Health and Disease: A Retrospective Clinical Study

This study retrospectively evaluated the effect of soft tissue condition on peri-implant health. Clinical variables (Plaque Index, keratinized tissue width, gingival biotype, and vestibular depth) were recorded. Probing depth, soft tissue recession, bleeding on probing, and radiographic marginal bone loss were assessed in relation to independent variables. Statistical analysis was performed using Mann-Whitney U test or Kruskal-Wallis rank test and a logistic regression model at the implant level. A total of 139 implants in 43 patients were assessed. Bleeding on probing was recorded at 54.7% sites, which was significantly related to the biofilm accumulation. Gender, history of periodontal disease, patient adherence to recall visits, and the presence of plaque were associated with higher peri-implant probing-depth values. The maximum soft tissue recession was recorded at sites with a thin biotype and shallow vestibular depth (P = .0). The logistic regression analysis revealed that plaque (P = .002) and vestibular depth (P = .043) were significantly associated with peri-implantitis. Within the study limitations, patients with high plaque accumulation and shallow vestibular depth are more prone to peri-implant disease.

Interactive Effects of Five Dental Implant Design Parameters on the Peak Strains at the Interfacial Bone: A Finite Element Study

PURPOSE

The aim of this study was to evaluate and compare the effect of changing five macrostructural design parameters of dental implants on the peak strains experienced by the interfacial bone.

MATERIALS AND METHODS

Five geometric variables, including three body-related (implant length, diameter, and taper) and two thread-related (thread depth and thread angle) parameters, were defined. The alveolar bone was modeled as a block with anisotropic and linearly elastic properties with 20-mm height and 12-mm buccolingual and mesiodistal dimensions. Oblique occlusal loads (100-N vertical and 20-N horizontal) were applied to the abutment surface. A total of 162 models with different designs were defined by implementation of a full-factorial design. The peak values of the compressive and tensile principal strains in the cortical and cancellous bones were calculated by finite element analysis (FEA).

RESULTS

Implant diameter and length had maximum and minimum effects on the peak compressive and tensile strains at the cortical interface, respectively. Implant diameter and thread depth had maximum and minimum effects on the maximum compressive strain at the cancellous interface, while thread angle and length had maximum and minimum significant effects on the maximum tensile strain at the cancellous interface.

CONCLUSION

The interaction of thread parameters and taper has the greatest effect on the peak compressive and tensile strains at the cancellous interface and also on the peak tensile strain at the cortical interface, while body-related parameters are more effective on the peak compressive strain at the cortical interface.

Physicochemical Changes of Contaminated Titanium Discs Treated With Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) Laser Irradiation or Air-Flow Abrasion: An In Vitro Study

Introduction: Peri-implantitis is a common complication of dental implant treatment. A cause-and-effect relationship has been previously documented between microbial plaque and peri-implantitis and implant failure. A difference has been reported in the disinfection efficacy of erbium laser irradiation and air-flow abrasion for contaminated titanium surfaces. Also, the surface changes caused by lasers and air-flow abrasion have not been well studied. Thus, the purpose of this study was to compare the surface changes of contaminated titanium discs following decontamination by erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation and air-flow abrasion. Methods: Twenty-eight intact, sandblasted, and acid-etched (SLA) titanium discs were used. Twenty-four titanium discs were contaminated with Escherichia coli. Then, they were decontaminated by using Er:YAG laser irradiation and air-flow abrasion. Four discs remained intact. The mean and standard deviation of the contact angle and the weight percentage of aluminum, titanium, oxygen, carbon, phosphorus, and calcium were measured. Qualitative changes in surface topography of titanium discs were assessed by scanning electron microscopy (SEM). Results: The mean weight percentage of carbon in the air-flow abrasion group (4.98%) experienced a significant reduction compared with the contaminated (positive control) group (P=0.035). The contact angles were 46.54° and 38.67° in the laser and air-flow abrasion groups respectively, which were significantly lower than the value in the positive control group (75.15°) (P ≤0.001). SEM micrographs showed no significant change in the surface area in either technique. Conclusion: Air-flow abrasion was more successful in improving the surface characteristics of titanium discs with no alteration in surface topography or elements, compared with Er:YAG laser irradiation. Further studies regarding the safety of the Er:YAG laser for the decontamination of titanium surfaces are recommended.

Peri-implant tissue health and disease in the pre- and post-loading phases

Considering the widespread use of dental implants, a precise definition for peri-implant tissue health and an appropriate classification for peri-implant diseases are imperative for researchers and dental clinicians. However, absence of a unanimous definition and an efficient classification system has created controversies in the published reports regarding the epidemiology and prevalence of peri-implant diseases. Moreover, lack of a standard system for differentiation of different grades of peri-implantitis further complicates the interpretation of reports regarding the diagnosis prevalence, treatment, and outcome of such conditions, and highlights the need for a classification system based on the severity of disease. Almost all of the currently available classification systems focus on the assessment of health or disease status of the tissues around loaded implants. The purpose of the present study is to propose a classification/scoring system for peri-implant tissue health before and after prosthetic loading. This grading system can aid the researchers and dental clinicians in assessment of peri-implant tissue condition both before and after prosthetic loading of dental implants.

Sinus floor elevation and simultaneous implant placement in fresh extraction sockets: a systematic review of clinical data

Combining different procedures to reduce the number of surgical sessions and patient discomfort in implant placement and sinus floor elevation has been recommended, and evidence supports good outcomes. The aim of this study was to review the results of clinical studies on sinus floor elevation through extraction sockets and simultaneous immediate posterior implant placement. An electronic search was carried out in PubMed, Scopus, and Web of Science to find English articles published in or before August 2020. A manual search was also performed. Titles, abstracts, and the full-text of the retrieved articles were studied. Thirteen studies met our eligibility criteria: 6 retrospective case series, 3 case reports, 2 prospective cohort caseseries, 1 prospective case series, and 1 randomized controlled trial. Overall, 306 implants were placed; 2 studies reported implant survival rates of 91.7% and 98.57%. The others either did not report the survival rate or reported 100% survival. Sinus floor elevation through a fresh extraction socket and simultaneous immediate implant placement appears to be a predictable modality with a high success rate. However, proper case selection and the expertise of the clinician play fundamental roles in the success of such complex procedures.

Effect of Schneiderian Membrane Thickening on the Maxillary Sinus Augmentation and Implantation Outcomes: A Systematic Review

Background

Schneiderian membrane thickness may influence the final clinical outcome of sinus augmentation and dental implantation. Mucosal thickening has been regarded as a contributing factor for post-treatment complications. This study aimed to systematically review the available literature on the association between mucosal thickening and potential complications related to sinus augmentation and implant placement.

Methods

An electronic search was carried out in MEDLINE, Embase, and Web of Science by two independent reviewers. It was complemented by manual search of the reference lists of all relevant studies. The studies reporting on sinus augmentation and dental implantation in cases with preoperative mucosal thickening were considered eligible for this study.

Results

The initial search yielded 1032 articles. Five hundred and sixty-four records were screened by title and abstract, and 57 studies succeeded the inclusion criteria for full-text evaluation. Finally, 10 records remained for data extraction. The included studies assessed sinus augmentation and implantation procedures in 765 patients, 324 (42.3%) of them showed mucosal thickening. Increased membrane thickness did not significantly elevate the frequency of sinus augmentation complications. In addition, the overall implant survival rate was 99.03%.

Conclusions

Within the limitations of the present study, the presence of mucosal thickening might not be a risk factor for sinus augmentation and implant survival rate.

Histopathological characterization of peri-implant diseases: A systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review of the inflammatory elements in peri-implantitis (PI) and peri-implant mucositis (PM) in comparison with healthy peri-implant tissues (HI) and periodontal disease.

DESIGN

The PubMed, Embase, Web of Science, and Scopus databases were searched up to December 2020. English articles that evaluated human soft tissue biopsies of PI or PM were included. Values reported for the surface area of the infiltrated connective tissue (ICT) were pooled using the random-effect model meta-analysis to estimate the mean (95% CI).

RESULTS

A total of 33 articles were included. Of 30 studies on PI, the majority evidenced significantly increased vascularization and inflammatory cell counts dominated by plasma cells in PI compared with HI. Studies that compared PI with chronic periodontitis primarily reported more severe inflammatory infiltrates in PI. This was confirmed by the meta-analysis results since the surface area of the ICT was significantly larger in PI (p < 0.001). Only seven studies analyzed the PM lesions and reported increased inflammatory infiltrates and vascularization in PM compared with HI. Based on the meta-analysis results, the surface area of the ICT was 3.00 [1.50, 4.51] mm ² in PI and 0.23 [0.02, 0.44] mm ² in PM lesions. Based on the available evidence, presence of foreign body particles considerably increased the inflammatory infiltrate; however, smoking did not have a significant effect.

CONCLUSIONS

There was controversy regarding the prevalence of various inflammatory cell types in peri-implant diseases; however, a considerably high ICT surface area in PI indicates the aggressive nature of the disease.

Clinical and radiographic evaluation of jumping distance management using a collagen matrix in flapless immediate implant placement

BACKGROUND

Improvement in implant design has made implant dentistry a challenging treatment modality worldwide.

OBJECTIVES

This study aimed to investigate the efficacy of a xenogeneic collagen matrix in managing 3-4-millimeter gaps in flapless immediate implant placement.

MATERIAL AND METHODS

Twenty-two patients received 39 immediate implants via the flapless approach. Patients with intact bony walls, buccal bone thickness ≥2 mm and a jumping distance of 3-4 mm were included in this study. The gap between the implant and the socket walls was filled with a xenogeneic collagen matrix (Collacone®). The final clinical and radiographic evaluations were performed at least 24 months following functional loading.

RESULTS

There was no early or late failure, and the implants showed a 100% survival rate. The mean mesial (0.28 ±0.39 mm) and distal (0.28 ±0.39 mm) marginal bone loss (MBL) at the site of incisors was not significantly different from the values at the site of premolars and molars (0.30 ±0.42 mm and 0.34 ±0.48 mm, respectively). The evaluation of the implant success index (ISI) score revealed no difference between the mandible and the maxilla (p = 0.700), or incisors compared with premolars and molars (p = 0.420). The only significant difference was in terms of distal MBL, which was higher in the maxilla (0.39 ±0.49 mm) than in the mandible (0.12 ±0.23 mm) (p = 0.040).

CONCLUSIONS

Within the limitations of this study, it seems that the application of a xenogeneic collagen matrix to manage 3-4-millimeter gaps in carefully selected cases may bring promising outcomes.

Bone quality and quantity of the mandibular symphyseal region in autogenous bone grafting using cone-beam computed tomography: a cross-sectional study

BACKGROUND

Bone volume plays a pivotal role in the success of dental implant treatment. Autogenous bone grafts should be harvested from reliable sites in the maxillofacial region. This study sought to assess the quantity and quality of bone in the mandibular symphysis for autogenous bone graft harvesting using cone-beam computed tomography (CBCT).

METHODS

This cross-sectional study evaluated the CBCT scans of 78 adults presenting to three oral and maxillofacial radiology centers. The vertical (VD) and horizontal (HD) alveolar bone dimensions, cortical thickness (CT), and cancellous to cortical bone ratio (C/C) were measured in the interforaminal region of the mandible at the sites of central incisor to first premolar teeth. The interforaminal distance (ID) and the anterior loop length were also measured. Nonparametric statistical tests were used to analyze the data with respect to sex, age, and tooth position.

RESULTS

The median VD, HD, and CT of the symphysis were 20.21 (3.26), 4.13 (0.37), and 2.25 (0.23) mm, respectively. The median C/C was 1.51 (0.11). The median ID was 52.24 (8.24) mm, and the median anterior loop length was 1.82 (1.06) mm. Significant differences were observed in all parameters among different teeth. Most of the measured parameters were greater in males compared with females. There were significant differences in ID, VD, and CT between different age groups.

CONCLUSIONS

The quantity and quality of the available bone in the mandibular symphysis for bone graft harvesting vary by gender, age, and harvesting site, necessitating careful preoperative evaluation.

Clinical Efficacy of Gingival Thickening Following the Use of Allogeneic Acellular and Xenogeneic Collagen Matrix: A 12-Month Randomized Clinical Trial

This randomized controlled clinical trial with a 1-year follow-up evaluated gingival thickness changes around teeth after use of dermal allograft and xenograft matrix. A total of 116 teeth (19 patients) were separated into two groups. One group received xenogeneic collagen matrix (n = 48), while the other received allogeneic acellular dermal matrix (n = 68) via a coronally advanced flap (CAF). Gingival thickness (GT), keratinized gingival width (KGW), pocket depth (PD), and clinical attachment loss (CAL) were measured on the day of surgery (baseline) and at 3 weeks, 2 months, 6 months, and 1 year postoperative. The two groups were compared using repeated-measures ANOVA (P < .05). The mean GT at 1 year was 1.59 ± 0.31 mm in the xenogeneic group and 1.63 ± 0.33 mm in the allogeneic group (P = .60). The mean change in GT was 1.08 mm in the xenogeneic group and 1.13 mm in the allogeneic group, which was clinically relevant and statistically significant compared to baseline values (P < .001). However, changes in GT were not significantly different between the two groups at any time point (P > .05). The GT increased in all cases treated with allogeneic and xenogeneic enriched collagen matrix. Both soft tissue substitutes were equally effective in acheiving optimal GT.

Bacterial Microleakage at the Implant-Healing Abutment Interface in Two Different Implant Designs: Platform Switching versus Platform Matching

This in vitro study aims to assess inward bacterial microleakage at the implant-healing abutment (IHA) interface in two different implant designs, namely platform switching (PS) and platform matching (PM). Five samples were collected from each of the PS and PM implant systems. In the first phase, healing abutments were tightened onto the implants by 10 Ncm torque. Next, IHA assemblies were immersed in an Escherichia coli (E. coli) suspension for 24 hours and 7 and 14 days. The healing abutments were then unscrewed, and samples were collected from the internal part of the implants and streak-cultured on culture media. After 1 day of incubation, the number of grown colonies was counted. In the second phase, the aforementioned steps were repeated for the assemblies that were torqued by 20 Ncm. Data were analyzed by the Kruskal-Wallis and Mann-Whitney tests (α = 0.05). The mean colony count was found to increase over time in the PM group torqued by 10 and 20 Ncm; however, this increase was only significant for 10 Ncm torque (P = 0.02). In the PS group, the colony count did not follow a certain pattern over time, neither in the 10 Ncm nor in the 20 Ncm torque. The mean colony count in the PS group was lower than that in the PM group at all time points in both torques. This difference was not significant at day 1, irrespective of torque value, but it was significant at 7 and 14 days, in both 10 and 20 Ncm torques (P < 0.05). Thus microleakage is lower in PS than PM design. The selection of a PM or PS design is a more important factor than the applied torque (10 or 20 Ncm) for reduction of bacterial microleakage in Tube-in-Tube implant systems with screw-retained connections.

Management of extensive peri-implant defects with titanium meshes

PURPOSE

Peri-implantitis is a biofilm-induced pathological condition, and different approaches have been proposed to manage this condition. This study introduces a surgical technique in accordance with the concept of guided bone regeneration for implants with extensive peri-implant defects.

METHODS

This pilot study was conducted on 7 patients with 11 implants (4 females and 3 males; 32 to 61 years). In this technique, we used a titanium mesh, a combination of autogenous bone, allogenic graft material, and acellular dermal matrix to reconstruct the peri-implant defects. All implants were placed submerged, and the second-stage surgery was conducted after 8 months. Soft tissue augmentation and vestibuloplasty were performed in the second-stage surgery, if required.

RESULTS

The mean function time of implants was 60.5 ± 29.4 months. The mean baseline probing pocket depth was 5.7 ± 1.4 mm, and soft tissue recession was observed at two sites (18%). The mean recession and keratinized tissue width (KTW) values were 0.4 ± 0.8 mm and 3 ± 1.6 mm, respectively. The mean marginal bone loss and bone gain were 4.4 ± 1.2 mm and 2.9 ± 0.9 mm, respectively, which showed a significant improvement.

CONCLUSION

Our preliminary evaluations showed favorable results in terms of radiographic defect fill and soft tissue condition. It appears that this technique may lead to promising outcomes in cautiously selected patients seeking to retain their failing implants. However, long-term results following functional loading are required before recommending this technique for daily practice.

Assessment of IL-10, IL-1ß and TNF-α gene polymorphisms in patients with peri-implantitis and healthy controls

Peri-implantitis (PI) is a multifactorial condition caused by the interactions of pathogens and the host immune response. Previous studies have demonstrated a relationship between PI and specific gene polymorphisms, particularly cytokine genes involved in the pathogenesis of PI. This study aimed to evaluate the frequency of single nucleotide polymorphisms (SNPs) of interleukin-10 (IL-10), interleukin 1ß (IL-1ß), and tumor necrosis factor-α (TNF-α) genes in PI patients and healthy controls. A total of 50 patients with PI and 89 periodontally healthy controls were recruited for this study. Venous blood samples (5 cc) were collected, and DNA was extracted. After DNA purification, the relevant gene segments were amplified by polymerase chain reaction (PCR). Restriction fragment length polymorphism (RFLP) and electrophoresis were performed to assess the polymorphisms of the related genes. The analysis revealed that allele and genotype frequencies of IL-10 ─ 819 C/T, IL-10 ─ 592 C/A, and IL-1ß + 3954 C/T significantly differed between PI patients and healthy controls. The analysis revealed no significant association between TNF-α ─ 857 G/A and TNF-α ─ 308 G/A polymorphisms and PI. Our results indicated that specific gene polymorphisms of IL-10 ─ 819 C/T, IL-10 ─ 592 C/A, and IL-1ß + 3954 C/T may play a role in the pathogenesis of PI, and increase its risk of occurrence.

Does COVID-19 Affect Periodontal and Peri-Implant Diseases?

COVID-19 has imposed tremendous burden on the healthcare systems and healthcare professionals worldwide. As periodontitis and peri-implantitis are chronic diseases, regular recall visits play a critical role in management of these conditions; however, the current situation may stop patients from attending their regular maintenance. Therefore, it may be necessary to reconsider and revise the treatment protocols.

Aphthous Stomatitis as an Uninvited Guest after Dental Implant Surgery: A Case Series

Objectives - Aphthous stomatitis is one of the most common ulcerative lesions in the oral cavity. The aim of this study was to report the characteristics of patients with aphthous stomatitis after dental implantation. Patients and Method - The study included 14 patients who were diagnosed with aphthous stomatitis. The subjects were analyzed with the respect to age, sex, patient's general health status, type, number, location, and duration of the ulcers and the number of dental implants. Results - Of the 14 cases, 64.3% were female and 35.7% were male. The mean age of patients was 57.7. In terms of general health status, 64.3% of patients did not have a remarkable disease; however, 14.3%, 14.3%, and 7.1% of cases had diabetes, hypothyroidism, and cardiac disease, respectively. The majority of the lesions have been presented as minor type (85.7%) and the mean number of the ulcers was 2.5. Labial mucosa has been affected more frequently (71.4%), followed by tongue and floor of the mouth. The most lesions (42.8%) were occurred one day after dental implant surgery. The mean number of dental implants was 3.1. Conclusion - Presence of apthous ulcers should be considered by dentists as a potential postoperative complication of dental implantation.

In Vitro Activity of Dental Pulp Stem Cells versus the Bone Marrow Stem Cells Cultured in Presence of a Bone Allograft

Introduction - Scaffolds and cells are two important components in bone tissue engineering. There is a gap of information about stem cell activity next to bone substitutes. Thus, the aim of this in vitro study was to compare the proliferation and differentiation of bone marrow stem cells (BMSCs) and dental pulp stem cells (DPSCs) in presence of freeze-dried bone allograft (FDBA). Method and Materials - DPSCs and BMSCs were cultured and placed on mineralized bone allograft. Cell proliferation was analyzed by the methyl thiazolyl tetrazolium (MTT) assay after 24, 48, and 72 h. To compare the enzymatic activity and mineralization of cells, the alkaline phosphate (ALP) test and alizarin red staining were performed at 30 days. Data were analyzed by ANOVA. Results - The rate of proliferation of DPSCs was higher at 48 and 72 h. ALP activity was significantly higher in DPSCSs (P < 0.05), while alizarin red staining did not show any significant difference between the groups in formation of calcified nodules. DPSCs showed higher cell proliferation and osteoblastic differentiation than BMSCs. Conclusion - Considering the easier and less invasive isolation of DPSCs, a combination of DPSCs and allograft can be a good choice for bone regeneration, especially in the dentoalveolar area.

Comparison of Periodontally Compromised Splinted Teeth and Implant Supported Fixed Partial Denture: A Three-Dimensional Finite Element Analysis on Bone Response

Introduction - This study aimed to compare the amount and pattern of stress and strain distributed around periodontally compromised splinted teeth and the two-implant abutments supported six-unit fixed partial denture (FPD) using finite element analysis (FEA). Methods and Materials - Six mandibular anterior teeth of a dental model were scanned and the scans were transferred to 3D CAD design and finite element software. Jaw bone was also designed and the teeth were splinted by fiber-reinforced composite (FRC) band. In another model, two implants were placed at the site of canine teeth and a six-unit FPD was designed over them. Models were transferred to finite element software and after meshing and fixing, they were subjected to 100- and 200-N loads under 0 and 30° angles. Results - Apical areas and crestal bone showed the highest accumulation of stress and strain in periodontally compromised splinted teeth. Crestal bone and bone between crestal microthread and the first thread of implant body had the highest accumulation of stress and strain in the implant supported six-unit FPD. Conclusion - The results showed significantly higher shear stress, von Mises stress and von Mises strain in peri-implant bone compared with bone around periodontally compromised teeth. Increase in applied load magnified this difference. Also, a greater difference was noted in stress and strain in bone around teeth and implants when oblique load was applied.

Structural and chemical features of xenograft bone substitutes: A systematic review of in vitro studies

Xenograft bone substitutes are obtained from different species and prepared by various procedures including heat treatment, hydrazine, and chemical and hydrothermal methods. These grafts are utilized widely because of similar structure and properties to human bone, proper bone formation, and biocompatibility. The aim of this systematic review was to evaluate different xenografts from structural and chemical aspects. In vitro studies published in English language, which assessed xenografts' features, met the inclusion criteria. Electronic search of four databases including PubMed, Google Scholar, Scopus, and Web of Science and a hand search until September 2020 were performed. The irrelevant studies were the ones which focused on cell adhesion and effect of growth factors. Finally, 25 studies were included in the review. Nineteen studies used bovine xenografts, and 12 studies applied heat treatment as their preparation method. Particles showed various morphologies, and their largest size was observed at 5 mm. From 18 studies, it is found that the smallest pore size was 1.3 µm and the highest pore size was 1000 µm. There is large heterogeneity of porosity, crystallinity, Ca/P ratio, and osteogenesis based on the preparation method. Proper porosity and the connection between pores affect bone regeneration. Therefore, biomaterial selection and outcomes evaluation should be interpreted separately.

Effect of Low- Level Laser Therapy on Bone Regeneration of Critical-Size Bone Defects: A Systematic Review of In Vivo Studies and Meta-Analysis

OBJECTIVE

Low-level laser therapy is a method for osteogenesis since it stimulates cell proliferation, vascularization and osteoblastic activity. Various protocols applying low-level laser with different outcomes exist. The aim of the present study was to review the result of different methods on bone formation in critical-size defects of in vivo studies.

DESIGN

According to PRISMA statement, electronic search of PubMed, google scholar, Scopus and Web of Science and a hand search limited to in vivo English language studies until December 2019. Studies used low-level laser therapy in bone regeneration of critical-size defects met the inclusion criteria and which used high power lasers or a defect size smaller than 5 mm, were excluded.

RESULTS

Finally, 18 studies were included. Fourteen studies utilized low-level laser with a wavelength ranging from 606 to 980 nm and 53 % of studies applied low-level laser in a single session. Ten studies utilized continuous wave mode of laser. Highest and lowest values of power density were 1.5 W/cm² and 0.1 W/cm² in order. Eleven studies evaluated low-lever laser therapy on defects of 5 mm in calvaria. Meta-analysis showed the positive effect of low-level laser therapy on osteogenesis after 30 days compared to control group and no significant difference after 60 days.

CONCLUSIONS

New bone formation can be increased in early stage by applying low-level laser therapy through stimulating osteoblasts and fibroblasts' proliferation. This effect would be more remarkable by combining with bone substitutes. Hence, for each case, protocol selection should be performed according defect's properties, attentively.

A compound of concentrated growth factor and periodontal ligament stem cell-derived conditioned medium

The aim of this study was to determine the in vitro effect of a compound of concentrated growth factor (CGF) and periodontal ligament stem cell-derived conditioned medium (PDLSCs-CM) as a potential product for future applications in periodontal tissue regeneration. Isolated PDLSCs were characterized using flow cytometry and differentiation into osteoblasts and adipocytes cells. PDLSCs-CM and CGF were prepared and lyophilized. To determine the optimal concentration of the CGF-CM compound, the proliferation of PDLSCs after exposure to a wide range of different concentrations of CGF, CM, or their combination (CGF + CM) was investigated by methyl thiazol tetrazolium assay. Successful isolation of PDLSCs was confirmed by high expression of mesenchymal surface markers and differentiation into osteoblasts and adipocytes. PDLSCs showed higher proliferation in the 6.25 mg/mL concentration of CM and 94 μg/mL concentration of CGF. High concentrations of CGF and CM markedly inhibited the proliferation of PDLCs (p < 0.05). The exposure of PDLSCs to the compound of 10% CM + 90% CGF significantly increased the cell proliferation (p < 0.05). The results showed that CGF, CM, or their combination exert a proliferative effect on cells at a certain concentration. Further investigation on the synergistic effect of this compound may approve its application for periodontal regeneration.

Comparison of osteopromoting ability of human tooth powder with the demineralized freeze-dried bone allograft, a bovine xenograft, and a synthetic graft: An in vitro study

Background

The present study aimed to evaluate the osteopromoting ability of human tooth powder and compare it to a bovine xenograft, a synthetic material, and the DFDBA allograft.

Methods

In this in vitro study, 30 teeth without caries, inflammation, and infection, which had been extracted for orthodontic reasons, were collected. The crowns were removed, pulpectomy was carried out, and the samples were ground to a powder with particles <500 µm. Osteoblast-like cells of MG-63 were cultured with the tooth powder, Cerabone, DFDBA, and Osteon II. Cell proliferation was assessed by the MTT assay at 24- and 72-hour intervals. The alizarin red test was carried out after three and five days. The alkaline phosphatase level was measured after 24, 48, and 72 hours to assess the osteoblastic activity. The results were analyzed with one-way ANOVA.

Results

According to the MTT assay, all the materials exhibited a higher proliferation rate than the control group in 24 hours. In 72 hours, DFDBA had the lowest cell proliferation rate at concentrations of 40 and 80 mg/mL. DFDBA and the positive control group were able to create calcified nodules by the alizarin red test. At the 48- and 72-hour intervals, DFDBA had the lowest alkaline phosphatase activity at a concentration of 40 mg/mL. At the 72-hour interval, bovine xenograft had the highest alkaline phosphatase level, followed by the synthetic material and tooth powder.

Conclusion

The tooth powder was able to increase cell proliferation in comparison with the bovine xenograft, the synthetic graft, and the DFDBA. However, its osteopromoting ability was less than that of the osteogenic materials.

Association of haptoglobin and natural resistance-associated macrophage protein 1 alleles with heme-consuming periodontal pathogens in chronic periodontitis and peri-implantitis: A pilot study

Background

This study aimed to assess the association of haptoglobin (HP) and natural resistance-associated macrophage protein 1 (NRAMP1) alleles with the presence of heme-consuming periodontal pathogens in a group of Iranian patients with chronic periodontitis and peri-implantitis.

Methods

This cross-sectional study evaluated 69 eligible chronic periodontitis and peri-implantitis patients selected from Shahid Beheshti Dental School. The periodontally diseased individuals had at least three teeth with clinical attachment loss of ≥3 mm and a probing pocket depth (PPD) of ≥3 mm in at least two quadrants. Peri-implant PPD of at least one site was ≥5 mm with or without suppuration and bleeding on probing. A plaque index of >20% and a radiographic crestal bone loss was present in at least one site around the implant. The paper point method was used for sampling from the deepest periodontal/peri-implant pocket of each tooth or implant for the DNA checkerboard hybridization technique. Statistical analyses were performed with PASW Statistics 18.0. The variables were presented as absolute and relative frequencies (%).

Results

An Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) score of 1–2 was 5.8 times more frequent in HP 2, rs1723540 G, and rs2276631 G alleles. A Porphyromonas gingivalis (P. gingivalis) score of 1–2 was 4.8 times more common in the subjects carrying HP 2, rs1723540 G, and rs2276631 G alleles compared with HP 1, rs1723540 A, and rs2276631 A alleles.

Conclusion

Within the limitations of this study, it seems that there was a relationship between HP and NRAMP1 allele frequencies and the presence of heme-consuming periodontal pathogens in the Iranian patients with chronic periodontitis and peri-implantitis evaluated in the present study.

Effect of gingival biotype on orthodontic treatment-induced periodontal complications: A systematic review

Background

It is crucial to maintain periodontal health in patients undergoing orthodontic treatment. Biotype is a critical factor to be considered in this regard. This systematic review investigated the scientific evidence on the relationship between gingival biotype and marginal periodontal alterations induced by orthodontic interventions.

Methods

An electronic search was conducted for pertinent studies in three databases: PubMed, Scopus, and Cochrane up to August 1, 2019 based on a detailed protocol according to the PRISMA statement. The authors also completed a hand search in six dental journals and the bibliographic lists of the relevant studies.

Results

Of 1512 citations retrieved through the electronic search, 602 were duplicate entries. By evaluating titles, abstracts, and full texts, eight articles conformed to the inclusion criteria; however, no relevant studies were found through hand searching. The evidence suggested that recession was inversely related with the thickness of the facial margin. These findings were more evident in proclined teeth and patients using fixed appliances.

Conclusion

The existing evidence suggests that orthodontic therapy might result in mild detrimental effects on the periodontium, especially in patients with thin biotype. However, due to the limited investigations and their inconsistent methodology, further well-designed prospective studies are necessary.

Clinical and Radiographic Assessments of Tooth Socket Preservation Using Leukocyte Platelet-Rich Fibrin

Leukocyte platelet-rich fibrin (L-PRF) has the potential to accelerate wound healing. Here, we assess clinical and radiographic outcomes of socket preservation using L-PRF. For this single-blind, randomized, split-mouth clinical trial, we selected 22 patients (15 males and seven females), who required extraction of single-rooted teeth. Subjects were randomly assigned to two groups. We used L-PRF in the extraction socket on one side and no material on the contralateral side. We obtained cone-beam computed tomographic images and diagnostic casts from tooth extraction sockets before surgery and 3 mo after the procedure. Changes in buccolingual diameter and height of bone at 3 mo after tooth extraction (compared to baseline) were determined and digitized data statistically analyzed using Statistical Package for the Social Sciences software, ver. 25.0 (IBM, Armonk, NY) via the paired t-test. In tooth sockets with/without L-PRF application 3 mo after extraction, bone buccolingual diameter significantly decreased at socket center to 0, 1, and 3 mm from the ridge crest, compared to baseline. A significant reduction occurred in sockets with/without L-PRF application in buccal and lingual bone height at the bony socket midbuccal portion of and mesial and distal septa (p < 0.0001). However, the Mann-Whitney U test showed changes to be significantly greater in controls than the case group (p < 0.0001). Taking into account study limitations, application of L-PRF in tooth extraction sockets significantly decreased reductions in bone height and buccolingual diameter compared to control sockets.

Effect of one and two sessions of antimicrobial photodynamic therapy on clinical and microbial outcomes of non-surgical management of chronic periodontitis: A clinical study

Background

This study aimed to compare the effect of one and two sessions of antimicrobial photodynamic therapy (aPDT) as an adjunct to scaling and root planing (SRP) on clinical and microbial parameters in patients with chronic periodontitis.

Methods

This study was conducted on 20 patients. The dental quadrants of patients were randomly assigned to SRP at baseline (group 1), SRP at baseline and one month (group 2), SRP plus aPDT at baseline (group 3) and SRP plus aPDT at baseline and one month (group 4). Probing depth (PD), clinical attachment level (CAL) gain, and bleeding on probing (BoP) were measured at baseline, and one and three months later. F. nucleatum counts were determined by PCR. ANOVA was used for the comparison of these variables between the groups.

Results

In all the groups, PD reduction and CAL gain increased significantly at 1- and 3-month intervals compared to baseline (P=0.001). At three months, the difference in PD between groups 1 and 3 was statistically significant (P=0.014). CAL gain between groups 2 and 4 at one month (P=0.016) and three months (P=0.001) wasstatistically significant. Reduction in F. nucleatum counts was not significant between the four study groups (P>0.05).

Conclusion

A combination of two sessions of aPDT and SRP could improve CAL gain; however, further long-term studies are necessary in this regard.

The Clinical Evaluation of the Effects of Low-Level Laser Therapy on the Donor and Recipient Sites of the Free Gingival Graft: A Case Series

Introduction: Free gingival grafting is among the most foreseeing procedures for increasing the zone of keratinized attached gingiva and enhancing soft tissue around the teeth and dental implants. Nowadays low-level laser therapy (LLLT) is a promising approach in providing patients with more pleasing results in terms of esthetics and comfort. This study aims to investigate the effects of LLLT on gingival recessions treated with free gingival graft (FGG). Methods: This case series was conducted on 12 individuals requiring a bilateral gingival graft in the mandibular region. There was a 30-day interval between the two operations. The test side was selected randomly and irradiated by a low-level laser (LLL) just before surgery. The patients did not know which side was irradiated. LLLT was applied to the donors' as well as recipients' site immediately after the operation and 48 hours later. The patients were instructed to record their post-operative pain in a visual analogue scale (VAS) 3 and 24 hours and 7 days after the surgical procedure. The clinical photographs were taken immediately and 30 days after surgical treatment were graded by three experienced periodontists for color matching to adjacent tissues. Results: Ten individuals could finish the study. The test group presented significantly better shade matching and wound healing at the palatal donor site on days 7, 14 and 21. There was a significant reduction in post-operative pain after 24 hours (P = 0.007). No statistically significant difference was found between both groups in terms of clinical periodontal indices. Conclusion: LLLT could reduce post-operative pain 24 hours after surgical treatment. Furthermore, the application of LLLT could improve the donors' site healing and the recipients' site color matching.

Finite Element Analysis of Dental Implants with and without Microthreads under Static and Dynamic Loading

The aim of this study was to assess stress and strain patterns in cortical and cancellous bones surrounding newly designed dental implants with different thread patterns. Static loading of dental implants has been well studied, but studies on dynamic loading and fatigue analysis of dental implants are scarce. This study analyzed the static, dynamic, and fatigue behaviors of dental implants using finite element analysis (FEA). Two models of dental implants were analyzed in this study. Model A was a tapered implant with V-shaped threads and model B was a tapered implant with microthreads in the uppermost region and V-shaped threads in the rest of the body. Two types of loading conditions were simulated in an FEA model and stress and strain patterns in the surrounding bone were analyzed. Dynamic loading increased the level of stress by 5-10% compared with static loading. Both implants showed acceptable results under static and dynamic loadings, but the second implant with microthreads caused lower stress and strain in cortical and cancellous bones. Dynamic and fatigue analyses can provide a more realistic understanding of the function of dental implants. Replacing the uppermost threads with microthreads can lead to more desirable stress patterns in bone, as well as a higher safety factor and longevity.

Association of Fc gamma-receptor genes polymorphisms with chronic periodontitis and Peri-Implantitis

This study was conducted on 87 patients with chronic periodontitis (CP), 50 patients with peri-implantitis and 90 periodontally healthy individuals referring to the Department of Periodontics for evaluating the association between Fc gamma-receptor genes polymorphisms with CP and peri-implantitis. After obtaining consent, venous blood samples (5cc) were obtained from patients and DNA was extracted using Miller's salting-out method. Polymerase chain reaction (PCR)-restriction fragment length polymorphism and tetra-primer amplification refractory mutation system-PCR methods were used to assess the polymorphisms of FcγRs IIa, IIIa, and IIIb genes. Analyzing showed a significant association between specific genotypes with increasing CP and peri-implantitis risks in codominant and dominant models. For FcγR IIIa, analyzing revealed a significant association between specific genotypes with increasing CP and peri-implantitis risks in codominant, dominant, and recessive models. For FcγR IIIb, we also detected a significant association between specific genotypes with increasing CP and peri-implantitis risks in codominant, dominant, and recessive models ( P < 0.05). According to the results of this study, the FCGRIIa (rs1801274), FCGRIIIa (rs396991), and FCGRIIIb (rs1050501) polymorphisms were significantly associated with CP and peri-implantitis and may have a role in the pathogenesis of these diseases.

Conservative Maxillary Sinus Floor Elevation via a Crestal Approach Using Vertical Expander Screw Technique (Technical Note)

OBJECTIVE

Contemporary implantology is moving toward less invasive approaches. To date, several techniques have been proposed for maxillary sinus lift surgery. In this article, we introduce a new technique for maxillary sinus floor elevation that is less invasive than the osteotome technique.

METHODS AND MATERIALS

In the vertical expander screw (VES) technique, which uses a combination of drilling and bone-expander screws; a primary implant hole is created. Bone expander screws are used in lateral and vertical dimensions to elevate the sinus membrane.

RESULTS

The results at the two-year follow-up revealed bone formation around the implant body in the bony sinus cavity for three patients. Accordingly, 100% survival and success rates were reported for implants placed with VES technique.

CONCLUSION

The maxillary sinus floor can be elevated to the desired height with a VES technique with minimal invasion. The VES technique can be used as an alternative to elevate the sinus floor with less invasion than the osteotome technique.

Histologic and Histomorphometric Assessment of Xenograft Bone Substitute versus Synthetic Nonceramic Hydroxyapatite for Canine Tooth-Socket Preservation

This study sought to histologically and histomorphometrically assess and compare application of xenograft bone substitute and synthetic nonceramic hydroxyapatite for tooth-socket preservation in dogs. This split-mouth clinical trial was conducted in five hybrid dogs, using four tooth sockets in each dog, with a total of 20 sockets for evaluation. Group 1 received xenografts, and group 2 received synthetic nonceramic hydroxyapatite in the sockets. In group 3 (positive controls), sockets remained empty. All sockets were covered with collagen resorbable membrane, and the flap was stitched using nonresorbable sutures. In group 4 (negative control), sockets were without membrane, left empty, and sutured. After 12 wk, 8-mm-high bone core biopsies were harvested from inside the sockets, using a trephine bur with an internal diameter of 2 mm. We assessed the tissue in terms of percentage of newly formed viable bone, percentage of remaining particles, degree of inflammation, and type of connective tissue. Data were statistically analyzed. The percentage of newly formed viable bone was 34.98% in group 1 and 41.30% in group 2, and this difference was not statistically significant (p = 0.710). The percentage of remaining particles was 15.95% in group 1 and 14.14% in group 2; this difference was also not statistically significant (p = 0.902). Both synthetic nonceramic hydroxyapatite and xenograft bone substitute showed similar efficacy, histologically and histomorphometrically, when used with resorbable collagen membrane for tooth-socket preservation in dogs.