nowadays , there are several restorative treatments alternatives for replacing a 
 missing tooth . over recent years
the rehabilitation of partially edentulous patients 
 with dental implants has become a well - established treatment .
replacement of missing teeth in the aesthetic zone presents a complex challenge for 
 the clinicians , due to the difficulty in restore the natural appearing sulcular and 
 papillae anatomy surrounding rehabilitated zones .
there are several studies that report similar success rates for 
 implants rehabilitation in the anterior region compared to those placed in other 
 parts of the jaws [ 4 - 6 ] .
cordioli et al . in 1994 , engquist et al . in 1995 
 and mcmillan et al .   in 1998 reported a 
 single - tooth implant restoration survival rate of 94.4% , 97.6% and 96% 
 respectively .
the long - term unpredictable stability of the soft tissues is one of the problems of 
 single - tooth implant rehabilitation for clinicians . in past decades ,
the 
 presence or absence of papillae between two teeth , a teeth and an implant and 
 between adjacent implants has been a topic widely discussed and important in oral 
 implants rehabilitations .
[ 12 - 14 ] related the presence or 
 absence of the interdental papilla to the distance of bone to the contact point 
 between the teeth and between teeth and implants .
dental implant abutment selection plays also an important role in achieving optimal 
 aesthetic results .
the computer - assisted 
 design / computer - assisted manufacturing ( cad / cam ) systems were incorporated in the 
 production of implant abutments and frameworks in the early 1990s and first applied 
 to titanium abutments [ 16 - 19 ] .
cad / cam abutment technique consists in a 
 computer program that reproduces the position of the implant and allows a correct 
 abutment design with an ideal shape and tilt .
assessed in their studies the precision at 
 the implant - abutment interface of cad / cam abutments . for optimal mucogingival 
 aesthetics , implant abutments
should have the appropriate emergence profile needed 
 to support the surrounding soft tissue and preferentially be made from 
 tooth - coloured material to prevent the bluish translucency of the overlying mucosa 
 [ 21 - 23 ] .
the aim of this study was to assess the clinical outcomes achieved 
 with computer - assisted design / computer - assisted manufacturing implant abutments in 
 the anterior maxilla .
nineteen patients ( 8 females and 11 males ) with a mean age of 41 years ( range form 26 
 to 63 ) who had been treated with 21 single tooth implants and 21 cad / cam abutments 
 in the anterior region of the maxilla were included in this study .
the selection of 
 the patients for the implant treatment included patients with teeth lost due to 
 traumatic injury , endodontic failure or traditional fixed prostheses failure . the 
 patients with edentulous sites due to periodontal disease
after the treatment , the patients followed 4 criteria of inclusion : ( 1 ) had a 
 single - tooth implant in the anterior maxilla , ( 2 ) had a cad / cam abutment , ( 3 ) had a 
 contralateral natural tooth , ( 4 ) the implant was restored and was in function for at 
 least 6 months up to 2 years .
the cases where did not exist contact point between 
 the implant and the teeth were excluded .
these patients were treated between january 2009 and january of 2010 in the 
 department of oral surgery and implant dentistry of private medical centre in 
 bragana and all signed the consent form in accordance with the helsinki 
 declaration of 1975 , revised in 2000 .
surgical and reconstructive treatment protocol the implants ( osseospeed , astratech dental , mhndal , sweden ) were placed over 
 delayed extraction sites , with a time of healing 7 to 8 weeks , or immediate 
 extraction sites were there no compromise of the buccal bone plate .
all the implants 
 were placed in the maxilla between teeth # 14 - 24 area and left to heal for a period 
 of 6 to 10 weeks , following a two - stage protocol ( figure 1 ) .
all 
 implants were then restored with screw - retained resin provisional crowns ( protemp 
 plus temporization material , 3 m espe , st .
the implants were then rehabilitated with a cad / cam abutment system 
 ( atlantis , atlantis europe , mhndal , sweden ) using zirconia and gold titanium 
 abutments ( figure 2 ) .
the zirconia abutments 
 were made of yttria - stabilized tetragonal zirconia polycristals ( y - tzp ) and the 
 titanium abutments used were milled from titanium alloy 6al-4v ( grade 5 ) blank and 
 then coated with thin layer of titanium nitride ( tin ) that provides the gold shade . 

the peri - implant soft tissue anatomy was copied with the use of a light - curing 
 composite resin added to fill the space between the soft tissue and the impression 
 coping to prevent the tissues from collapsing while the impression was being poured 
 ( figure 2c ) .
then both the diagnostic 
 model and master cast are scanned in order to initiate the milling process of the 
 abutment .
the virtual abutment design software accurately establishes the location , 
 orientation , angle and depth of the implant ( figure 
 3 ) .
all the abutments were then restored with all ceramic crowns , with 
 ceramic veneering in lithium disilicate ( ls2 ) ( ips e.max ceram , ivoclar vivadent ag , 
 schaan , principality of liechtenstein ) , placed over the cad / cam abutments . surgical treatment protocol : a and b = clinical status and radiographical 
 aspect of the tooth 23 ;
c = post - extraction socket ; d = implant placement in 
 the fresh socket .
prosthetic treatment protocol : a = screw - retained resin provisional crown ; b 
 = soft tissue emergency profile after 10 weeks with provisional restoration ; 
 c = implant - level impression ; d = cad / cam gold titanium abutment ; e and f = 
 ceramic restoration .
computer aided design of the abutments . follow - up evaluation protocol after a two - year period of the implant rehabilitation the 19 patients were recalled 
 as part of their recall program .
one patient was excluded of the study group since 
 it had no contact points between the implant restoration and the adjacent teeth . 

standard clinical and radiographic examinations were made , regarding the implants 
 situation in terms of survival and success .
the following parameters were evaluated : ( 1 ) presence / absence of the interproximal 
 papilla , ( 2 ) inter tooth - implant distance ( it d ) and ( 3 ) distance from the base of 
 the contact point to dental crest bone of adjacent tooth ( cpb ) .
interproximal papilla evaluation the presence / absence of the interproximal papilla was based in the pink aesthetic 
 score parameters for mesial and distal papilla   ( table 1 ) .
the inter - proximal 
 papilla was diagnosed as present if it filled up the entire proximal space and was 
 in good harmony with the adjacent papillae ; half - present if the proximal space was 
 half filled with the papilla and if less than half of the papilla was present the 
 diagnosis was absent papilla .
papilla pink aesthetic scores all implant crowns were captured with a digital slr camera ( canon eos 450d , canon , 
 tokyo , japan .
standardized clinical photographs ( magnification x1 ) were 
 taken at each implant site and the contralateral tooth .
the analyses were performed 
 by one experienced prosthodontist who had not been involved in the prosthetic 
 treatment of any patients represented in this study .
after 2 weeks a second set of 
 it d and cpb measurements was performed to evaluate the intra - observer variability . 
 the mean difference between the first and the second assessment was negligible .
radiographic assessment peri - apical radiographs were taken 24 months after definitive implant restoration 
 with the parallelism technique using intra - oral x - ray device ( heliodent plus , sirona 
 dental systems inc .
, ny , usa . xios intra - oral sensor system , sirona dental systems 
 inc .
a computerizing analysis were performed , using commercially 
 available software adobe photoshop cs5 ( adobe systems inc . ,
ca , usa ) to determine 
 inter - implant - tooth distance ( it d ) and the distance between the contact point to the 
 inter - dental bone ( cpb ) values ( figure 4 ) . 

the parameter chosen to set the measurement system was the distance between the 
 implant neck and the most apical point of each fixture , along an ideal line running 
 parallel to the long fixture axis .
if in the periapical radiographs were 
 found an overlapping zone with the adjacent tooth and the crown of the restored 
 implant , we accepted the medium point in the overlapping zone for effects of 
 measurement of cpb values .
computerized analysis performed to determine values of the 
 inter - implant - tooth distance ( it d ) and the distance from the base of the 
 contact point to the inter - dental bone ( cpb ) after converting the periapical 
 radiograph to a digitalized image .
a statistical analysis was performed using computer software spss , statistical 
 package for the social sciences , version 17.1 ( ibm corporation , armonk , ny , usa ) . 

twenty implants 
 placed in the anterior maxilla ( four in the site of 22 , seven in the site of 21 , 
 five in the site of 12 , one in the site of 11 and three in the site of 23 ) , were 
 evaluated .
forty interproximal sites , between tooth and implant were assessed , 
 regarding the papilla presence , it d and cpb values .
no implant failures were 
 reported in the two - year evaluation stage , resulting in a 100% implant success rate . 

clinical papilla radiographic assessments interproximal papilla evaluation an average mesial papilla score of 1.75 ( sd 0.44 ) mm and a distal papilla score of 
 1.7 ( sd 0.47 ) mm were achieved . at the mesial side ,
the papilla filled the 
 interproximal space completely at 75% of the sites and at the distal side the 
 papilla filled the interproximal space completely at 70% of the sites .
an overall 
 completely papilla filing was found in 72.5% of the sites and in 100% of the sites 
 the papilla was either completely or half present .
radiographic assessment a mesial it d average of 2.49 ( sd 0.69 ) mm and a distal it d average of 1.89 ( sd 0.63 ) 
 mm were achieved .
an overall cpb average of 5.11 ( sd 1.86 ) mm was determined , with a 
 mesial cpb average of 5.65 ( sd 1.65 ) mm and distal cpb of 4.65 ( sd 1.98 ) mm ( table 2 ) .
this study comprised a retrospective analysis of 20 dental implants , placed in the 
 maxillary anterior region , restored with cad / cam abutments . although the surgeon 
 skills and local anatomy play a major role in the peri - implant tissue stability , 
 clinical reports of the literature also tells us that custom abutments seem to 
 provide better results than stock abutments for ideal crown contours and 
 peri - implant soft tissue support . to 
 minimize the impact that the surgical skills might had in the final aesthetic 
 result , all the surgical procedures were carried out by an experienced implant 
 surgeon ( tb ) and were only included in the study group patients that received dental 
 implants with no associated extensive regeneration procedures .
a review on the 
 management of inter - dental / inter - implant papilla by zetu and wang   addressed factors that may influence its 
 appearance ; these mainly included the dimension of the inter - proximal space , the 
 horizontal distance between a tooth and an implant , adequate bone volume , the 
 presence of adjacent tooth attachment and a proper soft tissue thickness .
the parameters that affected the incidence of inter - proximal papilla between a tooth 
 and an implant were also examined by gastaldo et al .   in 48 patients ( 80 inter - proximal sites ) .
these authors 
 compared different parameters like the distance from the base of the contact point 
 to the bone crest ( d1 ) , the distance between a tooth and an implant or between two 
 implants ( d2 ) and the distance from the base of the contact point to the tip of the 
 papilla ( d3 ) and stated that when d2 was 3 , 3.5 or 4 mm , the papilla was present 
 most of the time and when d2 was 2 or 2.5 mm the papilla was absent 100% of the 
 time . when the distance between the contact point and the bone crest ( d1 ) was 3 , 
 3.5 , 4 mm the papilla was present 100% .
when the distance was 6 mm the interdental 
 papilla filled this space about 55% of the time and at 7 mm the interdental space 
 was completely filled about 25% of the time .
the results reported in the present study on the apico - coronal dimension of the 
 inter - proximal area are not confirmed by the investigation of gastaldo et al . .
in fact , for an overall cpb > 5 mm we 
 assessed an overall 72.5% completely papilla presence and at least half - presence of 
 the papilla in all the interproximal spaces assessed ( table 3 ) .
also , from the data collected we can report a papilla 
 presence in all the nine sites with an it d between 1 - 1.5 mm ( table 4 ) and completely papilla presence on 
 86.7% of the fifteen ( 15 ) sites with a cpb ranging 5.0 - 7.0 mm ( table 3 ) .
presence of inter - proximal papilla according to contact point to bone 
 crest distance ( cpb ) n = number of interproximal spaces evaluated . presence of inter - proximal papilla according to implant - tooth distance 
 ( it d ) n = number of interproximal spaces evaluated .
the results reported in the present study are also distant from the investigation by 
 choquet et al . .
although these authors 
 established that the papilla level around single - tooth implant restorations is 
 mostly related to the bone level adjacent to the teeth and more specifically to the 
 bone crest , they stated that the papillae regeneration after a single implant 
 treatment was successful with a distance of 5 mm between the contact point and the 
 bony crest . above 5 mm the occurrence of papilla regeneration
grunder   showed in his study that when an 
 implant is placed adjacent to a tooth , if a distance between the contact point and 
 the crest of bone was < 5 mm , results in a similar outcome in order to presence 
 or absence of papilla to that between two adjacent teeth .
this author presented ten 
 case reports of single - tooth rehabilitation and referred that all the papillae were 
 presented after crowns were placed .
the presence of healthy bone on adjacent tooth 
 and the location of the contact point at a distance of 5 mm or less were determinant 
 factors in grunder 's study . although the differences established by different 
 authors regarding the papilla position , its clear that a missing contact point , the 
 implant - to - tooth distance and the distance of the bone peak to the contact point 
 address as important predictors in terms of papilla recession , plus the surgical 
 approach or flap design . since the present evaluation was a retrospective analysis we must take notice of the 
 absence of a control group , and the lack of parameters that were not considered like 
 the type of surgical flap or the execution of some regeneration procedures .
the 
 attempt to correlate different parameters like it d and cpb and a papilla score , that 
 relates to a direct comparison between the implant restoration and the soft tissue 
 status around the natural control tooth seems to be an acceptable protocol to 
 evaluate aesthetic outcomes . in future 
 studies it would be interesting to relate this type of implant abutment restoration 
 with other abutment options for the anterior maxillary region , considering also 
 different timings of implant placement and related surgical procedures .
the restoration of dental implants using computer - assisted design / computer - assisted 
 manufacturing abutments appears to be a predictable treatment with improved 
 aesthetic results in anterior maxilla .
properly placement of the implant and correct 
 prosthetic considerations play a major role in the inter - proximal papilla 
 management .
the restoration of dental implants using computer - assisted 
 design / computer - assisted manufacturing abutments seems to improve the papilla 
 presence between tooth and implant .
 abstractobjectivesthe aim of this study was to assess the clinical outcomes achieved with 
 computer - assisted design / computer - assisted manufacturing implant abutments 
 in the anterior maxilla.material and methodsnineteen patients with a mean age of 41 ( range form 26 to 63 ) years , treated 
 with 21 single tooth implants and 21 computer - assisted 
 design / computer - assisted manufacturing ( cad / cam ) abutments in the anterior 
 maxillary region were included in this study . 
 the patients followed 4 
 criteria of inclusion : ( 1 ) had a single - tooth implant in the anterior 
 maxilla , ( 2 ) had a cad / cam abutment , ( 3 ) had a contralateral natural tooth , 
 ( 4 ) the implant was restored and in function for at least 6 months up to 2 
 years . 
 cases without contact point were excluded . 
 presence / absence of the 
 interproximal papilla , inter tooth - implant distance ( it d ) and distance from 
 the base of the contact point to dental crest bone of adjacent tooth ( cpb ) 
 were accessed.resultsforty interproximal spaces were evaluated , with an average mesial cpb of 5.65 
 ( sd 1.65 ) mm and distal cpb of 4.65 ( sd 1.98 ) mm . an average mesial it d of 
 2.49 ( sd 0.69 ) mm and an average distal it d of 1.89 ( sd 0.63 ) mm were 
 achieved . 
 papilla was present in all the interproximal spaces accessed.conclusionsthe restoration of dental implants using cad / cam abutments is a predictable 
 treatment with improved aesthetic results . 
 these type of abutments seem to 
 help maintaining a regular papillary filling although the variations of the 
 implant positioning or the restoration teeth relation . 
INTRODUCTION
MATERIAL AND METHODS
RESULTS
DISCUSSION
CONCLUSIONS
ACKNOWLEDGEMENTS AND DISCLOSURE