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Background: The osseointegration could revert unpredictably into a pathological process, resulting in inflammation and progressive bone loss causing peri-implantitis onset and implant failure. Even though the implant macro-design was created to accelerate the osseointegration pro- cess, it might be considered one of the implant- based factors contributing to peri-implantitis onset. Location and region of implant placement, as well as time in function, could be also proposed to affect peri-implantitis onset. Aim/Hypothesis: The study aimed to evaluate if implant macro-design parameters including implant body shape, number and shape of implant threads, and implant collar design compared to implant time in function could influence peri-implantitis onset. Material and Methods: 139 systematically healthy patients (55.17 ± 11.2 years old) with diagnosed an early or moderate stages of peri- implantitis on one or more endosteal or transmucosal implants were included in the study. Several clinical parameters (peri-implant probing depth, PPD, clinical attachment level, CAL, keratinized tissue width, KTW, plaque index, bleeding on probe), and implant based- factors such as implant location and region, and time in function (Tf) were evaluated and compared. Tf was defined as the time interval betw een implant loading and detection of peri-implantitis. In addition, implant macro-design parameters including implant shape (conic or cylindric), shape and number of implant threads, and implant collar design (polish or micro-threads) were assessed and compared to clinical data and Tf. All data were analysed using SPSS 20.0. A p-value less than 0.05 was considered statistically significant. Results: Peri-implantitis occurred approximately about 6.1 ± 3.4 years after implant loading. Statistical analyses failed to find a correlati on between patients' ages and implant macro- design regarding peri-implantitis incidence. Results demonstrated that implants with a cylinder shape as well as implants with tripe- threads had statistically significant higher rates of peri- implantitis in the posterior part of the mandible (P = 0.037, P = 0.012). "V"-shaped threads were found on all examined implants with diagnosed peri-implantitis. There was a statistically sig- nificant correlation between implant macro-design and Tf. Threads number and implant shape had a statistically significant influence on CAL and PPD increase, regarding Tf (P < 0.05). Longer Tf until peri- implantitis diagnosis could affect KTW decrease around implants with collar micro-threads (P < 0.001). Conclusion and Clinical implications: Peri- implantitis could be defined as a time- dependent disease. Clinical parameters exacerbation with further bone loss could be related to a prolonged time of peri- implantitis diagnosis as well as implant macro-design. Consequently, implant body design, thread number and shape, and collar design might be considered as possible implant- based risk factors in peri-implantitis onset and progression.

Background : Socket shield technique was introduced by Hurzeler and associates in year 2010., which is used at immediate implantation in order to preserve buccal wall bone. During tooth extraction, buccal root with periodontal ligament should be left in alveola and implant is inserted little bit towards palatal wall bone, in direct contact with buccal part of the root. As written above preservation of buccal bone and soft tissues has a huge influence on esthetic outcome of implant prosthetic work. Aim/Hypothesis : The aim of this clinical study was to investigate clinical success of the socket shield technique and to evaluate its outcome 6 years after surgical and prosthetic rehabilitation. Materials and Methods : This clinical study constituted of 30 patients with strong indication for tooth extraction in the frontal part of the maxilla. Patients were divided due to their clinical indications: Postendodontic horizontal tooth fracture where the fracture line is prosper enough to preserve buccal tooth root and immediate implant placement ; Postendodontic submarginal fracture when patient rejects orthodontic tooth extrusion ; Crown fracture of vital tooth beyond the marginal bone surface. In each group consisted of 10 patients. Partial resection of palatal root was performed in each patient with a view to preserve buccal root as well as buccal bone wall. Before implant was inserted a buccal root was smeared with Emdogain gel. Immediate crowns were made. After 4 months a permanent implant- prosthetic substitute was made, while x- ray analysis was made after 6 months, 4 years and after 6 years and esthetic (PES) evaluation has been made on clinical photo. Results : Patients did not have any kind of complications after surgery. Immediate crowns were replaced with permanent tooth crowns after 4 months. Soft tissue contours were preserved in all cases, also buccal bone wall was preserved after 6 months and after 4 and 6 years. In a period of following 6 years there were one biological complication regarding peri- implantitis after 5 years and that implant was lost. There were mechanical complications with 4 patients regarding screw loosening. All mechanical complications occured after 1 year in function and were resolved in one visit. The mean PES of evaluations after 6 years in function were 12.23 (±3.7 SD) regarding 12.78 after 6 months post implant and crown placement. Conclusions and Clinical Implications : With buccal bone wall preservation as well as a preservation of gingival tissue using technique of immediate implant placement, very good esthetic results were achieved. By deciding which patients are candidates for this surgery indications and guidelines written above need to be followed.

Background : A recent series of animal studies employing a canine model investigated the efficacy of extracted tooth roots for lateral alveolar ridge augmentation and two- stage implant placement Histological, immunohistochemical and micro- computed tomographic analyses of various outcome measures did not reveal any significant differences between tooth roots and autologous bone grafts used for lateral ridge augmentation (Becker et al., 2017 ; Schwarz et al., 2016 ; Schwarz et al., 2016). Aim/Hypothesis : The aim of this pilot clinical study was to assess efficacy and predictability of autologous tooth roots for lateral alveolar ridge augmentation and two- stage implant placement. Materials and Methods : In this pilot clinical case series, a total of 15 patients with 20 defects were included. Inclusion criteria were : age 18 to 60 years, candidate for lateral ridge augmentation, insufficient bone ridge width at the recipient site for implant placement, sufficient bone height at the recipient site for implant placement and healthy oral mucosa. Preoperative CBCT was made for every patient. After surgical removal of impacted tooth or periodontally compromised tooth and during the same surgery, the crown was decapitated at the cemento- enamel junction using a rotating carbide bur under water cooling and the exposed pulp was preserved. The separated tooth root was adapted to match the size and shape of the bone defect area. Grafts were drilled and fixed using one to two titanium osteosynthesis screw. After 6 months of healing commercially available Straumann BLT titanium implants were inserted and 3 months after screw- retained crowns were made. Results : After 6 months post implantation CBCT scans were obtained as part of the standard procedure. The radiographic images of the target areas revealed no signs for a graft separation from the recipient site. Clinical re- entry confirmed a homogeneous integration of tooth root grafts in the former defect area. This was evidenced by a firm graft connection to the host bone and a circumferential hard tissue formation. After 6 months CBCT scans were obtained as part of the standard procedure. The radiographic images of the target areas revealed no signs for a graft separation from the recipient site. Clinical re- entry confirmed a homogeneous integration of tooth root grafts in the former defect area. This was evidenced by a firm graft connection to the host bone and a circumferential hard tissue formation. In follow up period 1 year after there was no complications regarding implants or crowns. Conclusions and Clinical Implications : Within its limitations, the present pilot clinical study revealed that autologous tooth roots may serve as an alternative graft to support lateral alveolar ridge augmentation and two- stage implant placement.

Background : Peri- implantitis is an disease affecting the soft and hard tissue around implants, resulting in the loss of supporting bone. With the increasing popularity of zirconia dental implants, the need for effective and predictable decontamination protocols of the implant surfaces is becoming more and more important. Aim/Hypothesis : The aim of this study was to evaluate the effect of antimicrobial photodynamic therapy and light- activated disinfection on contaminated zirconia dental implants and investigate if the PDT and LAD cause implant surface alterations Materials and Methods : Seventy- two zirconia dental implants were contaminated with a bacterial suspension prepared from three different bacteria. After contamination, the implants were randomly divided into four test groups ( n = 12) according to the decontamination protocol- Group 1 (PDT1)- PDT (660 nm, 100 mW) with toluidine blue ; Group 2 (PDT2)- PDT (660 nm, 100 mW) with phenothiazine chloride dye ; Group 3 (LAD)- light emitting diode (LED) with toluidine blue ; Group 4 (TB)- toluidine blue without the application of light. In addition two control groups were used- the positive control (PC) group were treated with a 0.2% chlorhexidine- based solution, and implants assigned to the negative control (NC) group, did not receive any treatment.. The implants were analyzed using scanning electron microscope (SEM) to evaluate the possible surface alterations due to the PDT or the LAD protocols. Results : All study groups reduced the number of CFUs significantly compared with the NC ( P < 0.05) with more than 99% bacterial reduction. PDT1, the PDT2 and the LAD groups had the largest bacterial reduction, and were more efficient compared with the TB group ( P < 0.05). SEM analysis did not reveal any alterations of the implant surface after the treatment procedures. Conclusion and Clinical Implications : Both PDT protocols and the LAD showed high and equal effectiveness in decontamination of zirconia dental implants. Further clinical studies are needed in order to establish a clear and effective decontamination protocol of the zirconia implant surfaces using PDT or LAD.

Background : As dental implants are becoming a common dental treatment option, there is also an increase in the frequency of peri- implantitis. The main cause of peri- implantitis is considered to be the microorganisms living on the implant surface. The goal of treating peri- implantitis is to stop the inflammatory process and the bone loss that occurred as a result of the disease. Aim/Hypothesis : The aim of this study was to evaluate and compare the effect of antimicrobial photodynamic therapy and light- activated disinfection on contaminated titanium dental implants. In addition Scanning Electron Microscopy analysis was done to evaluate possible surface alterations on the implant surfaces. Material and Methods : The study was conducted on 72 titanium dental implants contaminated with a bacterial suspension prepared from three different bacterial species and were incubated in anaerobic conditions for 72 hours. The implants were randomly divided into four experimental groups and two control groups ( n = 12 each), according to the following treatment protocols- Group 1 (PDT1)- PDT with toluidine blue ; Group 2 (PDT2)- PDT with phenothiazine chloride dye ; Group 3 (LAD)- light emitting diode (LED) with toluidine blue ; Group 4 (TB)- treatment with only toluidine blue. In the positive control (PC) group, the implants were treated with a 0.2% chlorhexidine- based solution, and in the negative control (NC) group, no treatment was used. After microbiologic analysis, one random implant was chosen from each of the treatment groups, and one sterile nontreated implant was chosen for scanning electron microscopy (SEM). Results : The highest bacterial reduction was recorded in the PDT1 (98.3%) and PDT2 (97.8%) groups both having statistically significant reduction compared to NC group (

Background : A human periodontal ligament fibroblast cell line showed a very promising growth reaction to the mineralized dentin. The mineral and organic matrix compositions of a tooth, dentin, and cementum are almost identical to membranous bone, although, compared to bone, teeth contain more mineral. This feature may be beneficial for volume maintenance since at the remodeling stage dentin graft is resorbed slowly. As a supplement of bone graft material, dentin particulate autograft could be beneficial. Aim/Hypothesis : The aim of this pilot clinical study was to assess efficacy and predictability of dentin particulate autograft as regenerative treatment for alveolar ridge augmentation and two stage implant placement using CBCT radiographic analysis. Materials and Methods : The sample of presented study consisted of 8 patients, with insufficient width of alveolar ridge in lateral lower jaw. After surgical removal of third molar or periodontally compromised tooth, a dentin autograft was prepared according to manufacturer recommendations. Clean extracted teeth were dried and ground in a sterile chamber of the Smart Dentin GrINDIAr ® unit (KometaBio Inc., Cresskill, USA). The particulate teeth were immersed in a basic alcohol cleanser to dissolve all organic remnants and bacteria and dehydrated. The particles were rinsed twice with sterile phosphate- buffered saline solution. The platelet- rich fibrin (PRF) membranes were prepared. Graft material was used for ridge augmentation and covered with PRF membranes. After 5 months of healing CBCT scan were made. During implants placement homogeneous integration of dentin particulate was found. Dental implants (BEGO Semados ® SC BEGO, Germany) were inserted and restored by titanium abutment and zirconia crown. Results : Clinical re- entry, prior to dental implants placement confirmed a homogeneous integration of dentin autograft and bone- like appearance in former grafted area. Six months after implants placement CBCT scans were obtained as part of the standard procedure. The radiographic images of the target areas revealed no grafted bone resorption around the implants. All patients were followed for 6 months after loading through clinical follow- ups and control CBCT scans. No resorption of the autograft around inserted implants were found. Conclusions and Clinical Implications : Within its limitation, the present pilot clinical study revealed that autologous dentin particulate autograft may serve as an alternative autologous bone substitute to support alveolar ridge augmentation and two- stage implant placement.

Background : Bone healing processes following osteotomy may vary according to the type of selected surgical procedures. Frictional heat caused by traditional bur osteotomies may result in thermal osteonecrosis if the temperature arises above the critical temperature of 47º C. Therefore, less invasive and precise tools for bone tissue surgery with reduced collateral tissue thermal trauma, force and friction are developed: laser- assisted bone surgery and piezoelectric surgery. Aim/Hypothesis : The purpose of the present in vivo experimental study was to determine the thermal changes of the bone tissue following osteotomies performed by piezoelectric surgery, surgical drill and Er:YAG laser- assisted ablation used in contact and NO- contact modes using infrared thermographic camera. Materials and Methods : A total number of 24 Wistar rats were randomly divided into 4 groups, each consisting of 6 rats (I- sacrificed immediately after surgery ; II- 7 days after surgery ; III- 14 days after surgery ; IV- 21 days after surgery). Osteotomies on both rat ' s tibiae were performed under general anesthesia and always in the same sequence: digitally controlled NO- contact Er:YAG laser (7.5 W, 750 mJ, 10 Hz, QSP mode), piezosurgery (round diamond tip, 1.2 mm diameter, average pressure 15 N), low- speed surgical drill (1200 rpm, round steel surgical bur 2 mm diameter) and contact Er:YAG laser (H- 14N handpiece, fiber of core diameter of 940 μm, 7.5 W, 375 mJ, 20 Hz, MSP mode). The osteotomies were 5 mm away from each other and ~2 mm deep, with a diameter ranging between 1.5–2.0 mm. Temperature measurements during each osteotomy were done using an infrared thermographic camera with a detection range of - 20º to + 650º C, a thermal sensitivity of < 50 mK, and IR resolution of 320x240 pixels. Results : For each osteotomy a thermal camera movie was recorded and movie frames were extracted as thermal camera images, and the position of the osteotomy was determined by visual inspection. Temperature readout was performed for this point in all recorded movie frames, providing the information on the temperature at the position of osteotomy while osteotomy was performed. Time evolution of the bone temperature at the point of osteotomy was measured. For each measurement, baseline temperature (Tbase), and maximum temperature measured during the osteotomy (Tmax) were determined. ΔT=Tmax- Tbase was then calculated for each measurement. Mean baseline temperature for each group of osteotomies was 29.96°C for non- contact laser, 27.98°C for contact laser, 28.34°C for surgical drill and 29.39°C for piezosurgery. Mean Tmax for contact laser was 29.92 °C (ΔT=1.94 °C), for non- contact laser was 79.11°C (ΔT=49.15 °C), for surgical drill was 27.36°C and 29.15 °C (ΔT=- 0.24 °C) for piezosurgery. Conclusions and Clinical Implications : The results of the present study showed beneficial effects of the piezosurgery and Er:YAG laser used in contact mode of working on heat generation of bone tissue during osteotomy, reducing potential overheating of the bone as registered by means of infrared thermography. Digitally controlled non- contact Er:YAG laser results in the production of temperature that is higher than the allowed border for bone tissue during osteotomy.

Background : Socket shield technique was introduced by Hurzeler and associates in year 2010., which is used at immediate implantation in order to preserve buccal wall bone. During tooth extraction, buccal root with periodontal ligament should be left in alveola and implant is inserted little bit towards palatal wall bone, in direct contact with buccal part of the root. As written above preservation of buccal bone and soft tissues has a huge influence on esthethic outcome of implant prosthetic work. Aim/Hypothesis : The aim of this clinical study was to investigate clinical success of the socket shield technique and to evaluate its outcome 4 years after surgical and prosthetic rehabilitation. Material and Methods : This clinical study constituted of 21 patients with strong indication for tooth extraction in the frontal part of the maxilla. Patients were divided due to their clinical indications: 1. Postendodontic horizontal tooth fracture where the fracture line is prosper enough to preserve buccal tooth root and immediate implant placement 2. Postendodontic submarginal fracture when patient rejects orthodontic tooth extrusion. 3. Crown fracture of vital tooth beyond the marginal bone surface, but patient is not willing to access orthodontic therapy or conservative treatment. In each group consisted of 7 patients. Partial resection of palatal root was performed in each patient with a view to preserve buccal root as well as buccal bone wall. After resection alveolar bed for implant, located more palatal regarding on buccal root left in alveola, was prepared. Before implant was inserted a buccal root was smeared with Emdogain gel (Straumann, Basel, Switzerland). After all, immediate crown was made following non- functional loading concept. Patients were threaded with antibiotic therapy during 7 days after surgery. After 4 months a permanent implantoprosthetic substitute was made, while x- ray analysis was made after 6 months and after 4 years all patients were controlled by x - ray analysis and esthethic evaluation has been made. Results : Patients did not have any kind of complications after surgery. Immediate crowns were replaced with permanent tooth crowns after 4 months. Soft tissue contours were preserved in all cases, also buccal bone wall was preserved after 6 months and after 4 years. In a period of following 4 years there were no biological complications. There were only mechanical complications with 4 patients regarding screw loosening. All complications occured after 1 year in function and were resolved in one visit. Conclusions and Clinical Implications : With buccal bone wall preservation as well as a preservation of gingival tissue using technique of immediate implant placement, very good esthetic results were achieved. By deciding which patients are candidates for this surgery indications and guidelines written above need to be followed.

Background : Bone drilling is a common step of an everyday procedure in dental implantology. Frictional heat from these osteotomies may result in thermal necrosis of bone. Bone temperature must be below the temperature of 47°C during drilling to avoid thermal osteonecrosis. Many factors (drill design, drilling parameters, coolant delivery) contribute to heat generation during osteotomy. Consequently, superior methods of bone tissue surgery, which would enable reduced collateral tissue thermal trauma, force and friction, has been developed including erbium laser ablation and piezoelectric surgery. Aim/Hypothesis : The purpose of the present experimental study was to determine the thermal changes of the bone tissue following osteotomies performed by piezoelectric surgery, and Er:YAG laser ablation used in contact and non- contact modes using infrared thermographic camera. Material and Methods : A total number of 24 Wistar rats were used in this study, randomly divided into 4 groups, based on the post- operative duration of survival of the animals. Osteotomies on both rat ’ s tibiae were performed under general anaesthesia by an intraperitoneal injection of thiopental sodium. Four osteotomies were performed always in the same sequence: digitally controlled non- contact Er:YAG laser (X- Runner™, Fotona, Slovenia), piezosurgery (Piezomed, W&H Dentalwerk Burmoos GmbH, Austria) and contact Er:YAG laser (LightWalker ® , Fotona, Ljubljana, Slovenia). The osteotomies were 5 mm away from each other and 2 mm deep, with a same diameter. Temperature measurements during each osteotomy were done using an infrared thermographic camera (FLIR T335, FLIR Systems Pty Ltd, Australia) with a detection range of −20°C to +650°C, a thermal sensitivity of

Background : Implant abutment selection is the crucial moment in implant prosthodontics treatment. Abutments can generally be divided into two main groups: stock and custom. For several years, stock abutments have been the only option available for clinicians. Custom made CAD/CAM abutment acts as adequate support for soft tissues, and the connection between abutment and a cement- retained crown is moved more towards coronal, which makes residual cement removal easier during cementation of a prosthetic restoration. Aim/Hypothesis : The aim of this study was to compare stock and individual CAD/CAM abutments after one year in function. A total of 64 subjects with one missing tooth, were included in this study. The missing tooth was replaced with a dental implant, an abutment and a porcelainfused- to- metal crown. Material and Methods : A total of 64 subjects had a single tooth loss restored by dental implant and porcelain- fused- to- metal crowns were fabricated. In one group there were a total of 34 stock Ti abutments and in the second group of subjects 30 CAD/CAM made Ti abutments. Examination of soft tissues around dental implants included determination of modified plaque index (mPI) and modified bleeding index (mBI), as well as measurement of sulcus probing depth (PPD). The average modified plaque index (mAPI) was calculated from the measured values, as the average measurement value on all four crown surfaces. The average modified bleeding index (mABI) was calculated in the same way. PPD measurement was performed on the mesial, distal, vestibular and lingual crown surface, and the average values of measured probing depth (APPD) were calculated. The values mAPI, mABI and APPD were measured during the first check- up (a week after cementing the crown) and at check- ups after 4, 8 and 12 months. Results : Average plaque index values (API), initial and after 4, 8 and 12 months, have not indicated significant differences between two groups of subjects. Average bleeding index values - initial (i- ABI) and after 4 months (4 m- ABI) revealed no significant differences between two tested groups. However, there was significant difference in the average bleeding index values after 8 months (8 m- ABI) between the two tested groups (Mann Whitney ’ s U test P = 0.002). Significant difference (Mann Whitney ’ s U test P < 0.001) was also observed for the average bleeding index values after 12 months (12 m- ABI) between the two groups of subjects. There was no significant difference in the mean values of probing depths between two groups of subjects. Conclusions and Clinical Implications : The results of this study showed that the impact of the abutment type (individual CAD/CAM or stock) on the average bleeding on probing was significant, especially after 8 or 12 months. The level of oral hygiene showed significant correlation with the average bleeding on probing.

Background : The autologous platelet concentrates Platelet- Rich Plasma (PRP) and Platelet- Rich Fibrin (PRF) are used in various medical fields, particularly in oral and maxillofacial surgery. Platelet- rich fibrin (PRF) is derived from an autogenous preparation of concentrated platelets that contains high levels of polypeptide growth factors and therefore has the potential to be used as regenerative treatment for bone defects. Growth factors are the key elements in wound healing, particularly in bone regeneration. Aim/Hypothesis : The purpose of this study was to examine the suitability of autologous PRF transplant in combination with xenograft as regenerative treatment for maxillary sinus augmentation in humans and compare it to xenograft alone using densitometric measurements. Material and Methods : The sample of presented study consists of 10 patients partially edentulous in the lateral region of the upper jaw. Lateral approach for maxillary sinus augmentation with immediate placement of two dental implants were used for all patients. In the first group of 5 patients sinus augmentation was performed using xenographic bone graft (Bio- Oss ® , Geistlich, Germany) only and finally covered with resorbable collagen membrane (Bio- Gide ® , Geistlich, Germany). In the second group of 5 patients sinus augmentation was performed using combination of autologous PRF and xenograft (Bio- Oss ® , Geistlich, Germany) and covered using combination of resorbable collagen membrane (Bio- Gide ® , Geistlich, Germany) and PRF membrane. Following the healing period of 6 months, the osseointegration of inserted implants was assessed with resonance frequency analysis and considered adequate. All inserted implants were loaded with metal- ceramic restorations. All patients were followed for 5 years after loading through clinical follow- ups and digital radiographic imaging after 6, 12, 18, 24, 48 and 60 months. Densitometric analysis was performed based on radiographic images using customized software. Results : After comparing the average densities of all inserted implants, the results showed statistically significant increase of density in group of patients where combination of xenograft and autologous PRF transplant for sinus augmentation was used. Conclusions and Clinical Implications : The results of this study indicate that PRF can improve densitometric parameters associated with maxillary sinus floor elevation procedures and immediate implant placement, improving clinical implant stability and promoting bone healing following augmentation. PRF can be used as an effective modality for promoting bone healing and osseointegration process.

Background : Piezosurgery and different types of high- energy lasers have been investigated in bone surgery. Immediate physiologic response to bone injury is a local and systemic inflammatory reaction. The biologically relevant metabolites of arachidonic acid are the families of prostaglandins, thromboxanes, leukotrienes, and lipoxins. Among them, leukotrienes (LTs) are the most prominent molecules with a wide variety of functions. There are no reliable data concerning LTs metabolism during bone healing after Er:YAG laser or piezosurgery osteotomies. Aim/Hypothesis : The objective of the present study was to analyse the healing of the bone tissue treated with the short- pulsed infrared erbiumdoped yttrium aluminium garnet laser in contact and non- contact mode and piezosurgery in relation to circulatory leukotriene B4 (LTB4) and Cysteinyl leukotrienes (Cys- LTs) (LTC4, LTD4, LTE4 and LTF4). Material and Methods : Twenty- four 10- week- old adult male Wistar rats were used in the study. Osteotomies on both rat ’ s tibiae were performed under general anaesthesia by an intraperitoneal injection of thiopental sodium. Three osteotomies were performed always in the same sequence: digitally controlled non- contact Er:YAG laser, piezosurgery and contact Er:YAG laser. The osteotomies were 5 mm away from each other and 2 mm deep, with a same diameter. Animals from the first group were euthanised immediately after performing osteotomies, with an overdose of anaesthetic solution. The animals from the second group were sacrificed after 1 week, from the third group after 2 weeks and from the fourth group after 3 weeks, all with an anaesthetic overdose. After euthanasia blood was taken from the abdominal aorta and collected for further analysis of leukotriene B4 and cysteinyl leukotrienes. Bone healing after osteotomy was analysed using a laser- based profilometric system and compared to circulatory leukotrienes level. Results : The circulating levels of both LTB4 and Cys- LTs at 7 and 14 days after osteotomies, were significantly decreased in comparison with the initial ( P < 0.001 for LTB4 and P < 0.05 for Cys- LTs). On the 21st day after surgical treatment only circulating levels of the LTB4 were significantly decreased compared with those on the day 7 ( P < 0.001) and 14 ( P < 0.05) and then on the day 21 after surgical procedures they were close to the initial ( P = 0.912). Circulatory Cys- LTs after day 21 were slightly increased compared with those on the day 7 and 14, but still didn ’ t reach the levels of the initial group ( P = 0.112). On the 21st day, there were negative significant correlation between LTB4 and reduction in osteotomy volume for all three surgical treatments ( P = 0.012,  = −0.431, related to piezosurgery ; P = 0.045,  = −0.398, related to Er:YAG contact mode and P = 0.033,  = −0.342 related to Er:YAG non- contact mode, respectively). The circulating Cys- LTs, showed negative significant correlation with the reduction in the osteotomy volume only after Er:YAG contact mode ( P = 0.018,  = −0.456). Conclusions and Clinical Implications : It is clear that the applied surgical techniques foster mechanisms of LT ’ s suppression. Taking the fact that different players (especially products of the cyclooxygenases), are involved in the regulation of the LT ’ s production during the process of bone healing, further studies are needed to reveal exact mechanisms involved in different phases of the bone healing process after an Er:YAG or piezosurgery osteotomy. This can help in the development of new approaches that will target partial LTs and will effectively improve the bone healing at whole.

Background : A recent series of animal studies employing a canine model investigated the efficacy of extracted tooth roots for lateral alveolar ridge augmentation and two- stage implant placement Histological, immunohistochemical and micro- computed tomographic analyses of various outcome measures did not reveal any significant differences between tooth roots and autologous bone grafts used for lateral ridge augmentation. (Becker et al., 2017 ; Schwarz, Golubovic, Becker, et al., 2016 ; Schwarz, Golubovic, Mihatovic, et al., 2016). Aim/Hypothesis : The aim of this pilot clinical study was to assess efficacy and predictability of autologous autologous tooth roots for lateral alveolar ridge augmentation and two- stage implant placement. Material and Methods : The patient had to be fully able to understand the nature of the proposed surgery and able to sign an informed consent form. Inclusion criteria were : age 18 to 60 years, candidate for lateral ridge augmentation, insufficient bone ridge width at the recipient site for implant placement, sufficient bone height at the recipient site for implant placement and healthy oral mucosa. Preoperative CBCT was made for every patient. After surgical removal of impacted tooth or periodontally compromised tooth and during the same surgery, the crown was decapitated at the cemento- enamel junction using a rotating carbide bur under water cooling and the exposed pulp was preserved. The separated tooth root was adapted to match the size and shape of the bone defect area. To improve ankylosis between the graft and the defect site, the layer of cementum at the respective downward aspects of the root was carefully removed using a diamond bur until the underlying dentin was entirely exposed (Schwarz, Golubovic, Becker, et al., 2016). To improve the contact between tooth roots the recipient site was gently flattened using a round carbide bur under meticulous water cooling. Grafts were drilled and fixed using one to two titanium osteosynthesis screw (1.5 × 9.5 mm, Helmut Zepf, Germany). All patients were provided with a perioperative antibiotic (1 × Amoxicillin with clavulanic acid 2 g) as well as a peri- and postoperative (2 days) antiphlogistic prophylaxis (dexamethasone, total of 16 mg). Analgesics (ibuprofen 600 mg) were prescribed and used as necessary. Suture removal was performed at 10 days postoperative. After 6 months of healing, a mucoperiosteal flap was elevated to expose the target site and after removal of the osteosynthesis screw, commercially available titanium implants (Bone Level ® Tapered SLA ® , Institut Straumann AG, Basel, Switzerland) were inserted. Results : After 6 months CBCT scans were obtained as part of the standard procedure. The radiographic images of the target areas revealed no signs for a graft separation from the recipient site. Clinical re- entry confirmed a homogeneous integration of tooth root grafts in the former defect area. This was evidenced by a firm graft connection to the host bone and a circumferential hard tissue formation. Conclusion and Clinical Implications : Within its limitations, the present pilot clinical study revealed that autologous tooth roots may serve as an alternative graft to support lateral alveolar ridge augmentation and two- stage implant placement.